M4 (Tamiya) Build #7 – Finishing the Gimmick of See-Through Panels, Getting Started on the Turret Basket, and MAKING that Sodding Upper Hull Fit to the Lower Hull
I left off with the turret being ready to have its clear panel installed, so (oddly enough) I started installing the clear panel. There’s only so much fitting that can be done because each time it’s fitted, there are subtle differences in alignment and at some point the thing just has to be glued in. I’m attaching resin to plastic so superglue is used:
Then the gaps around the clear panel get stuffed with scrap styrene, primarily 0.005″ (.127mm), 0.010″ (.254mm), with a bit of 0.020″ (.508mm) for diversity:
Anyone that’s been building models for any length of time knows that these things, and particularly shape and dimension, will vary depending on how any given manufacturer goes about it. And all of these things vary, even when one is working the same subject in the same scale in the same area. Whichever manufacturer’s turret was used as the starting point for the clear turret I sourced this panel from was different from Tamiya’s turret and the actual curve(s) differed, resulting in something that didn’t quite match:
The shape differed no matter which angle I looked at it from; the above photo is shows the differences (and there were a few). Having spent a few hours filing, sanding, grinding, and polishing, I was most eager to go through that process again (I hope you realize that was sarcasm), starting with the filing step. Once this had been filed so that all curves matched, sanding and polishing followed (I managed to avoid the grinding step) to restore what transparency the medium (resin) would permit:
Seeing as the remaining gaps were so small, I tried something different and used Vallejo’s Acrylic Resin Plastic Putty #70.401 to fill them:
I don’t intend to trash this product. There are probably those who use it and like it. Until this project, I’ve only used this putty to replicate weld beads and have liked the result. Once the putty cured overnight, I started sanding it and didn’t like how that went. The putty came up in chunks without really bonding to either the plastic or the resin. Having tried something new for me, I removed all the Vallejo putty and went back to using my preferred product for this task, 3M’s Acrylic Putty which worked as well as it always does.
While the putty was curing, I started work on the clear panel for the hull. That started by outlining the area I wanted to excise and replace with clear styrene:
Then there were many, many, passes with a panel line scriber to dig through the plastic. I got the outline subtly off and didn’t notice that I bobbled the lower left where the curve meets the lower line (because caffeine levels in the bloodstream vary over the course of a day). I cut the error square (ish), inserted scrap styrene, and reworked the curve while cleaning up the jagged edge left by the scriber. The upper hull was dry-fitted to see if I had achieved what I was trying for:
[It’s at this point that we’re having a quiz. I have overlooked something that I didn’t notice until later in the month. The question to you is, have you figured out what I overlooked? The answer will be revealed at the point in the build where it finally dawned on me.]
With the opening defined, it was time to cut a piece of 0.015″ (.381mm) clear styrene to fill it:
Rather than attempt a rather long butt joint by cutting the clear insert to the dimension and shape of the hole, I decided to carve a depression of about 1/8″ (.0625″ or just under .2mm) wide for the styrene to settle into:
As you may have noticed in the above photo, what is the bottom of the hull’s side is a long and narrow strip of plastic. The line that crosses it perpendicularly is where it snapped. Significant pressure is required to scrape away the plastic and you can see that I didn’t get very far along before it snapped. I knew there were fairly large gaps where the sponsons met the upper hull so I had the room to use 0.010″ (.254mm) styrene to back the long and narrow strip. Even with the backing, because plastic is flexible, the break kept opening. I widened the gap of the break and inserted a scrap of 0.010″ (.254mm) to provide strength to the repair. It worked because during the rest of the excision, it didn’t break again.
It took some time but I finally got what I was after (I thought):
I didn’t realize before I had glued the clear panel in place (probably a drop in caffeine levels) that the depression I’d scraped into the plastic wasn’t quite uniform in depth. (If I ever do something like this again, I will jig a tool that will show me when I have reached the intended depth.) By the time I came to that realization I had already glued the clear in quite firmly and didn’t want to even try to remove it. Lesson learned, continue on.
I was most careful with the glue (Tamiya’s Super Thin). I got almost all the way around the periphery with the gluing process before an errant nerve pulse (twitch) caused my ancient hand to bobble the glue. In the following photo you can see where that happened at the bottom right of the clear panel:
Not optimal but by this point, the process of this built has increased my depth of experience with getting something that isn’t clear to become clear.
With a lot of puttying and sanding pending, I wanted to mask the sections I want to stay clear. Since I will also need to mask the inside (because, painting, y’know), I started there. It will make aligning the masked-off area match on both sides easier to start inside the hull and match that from the outside:
Then mask the outside to match:
“Insanity can be defined as doing the same thing over and over while expecting different results each time.” Yeah. That would be (and frequently is) me. Don’t ask me why because I have no answer that makes sense (even to me), but I tried using Vallejo’s putty again:
Probably surprising only me, it worked as well as it didn’t on the turret. ::face palm:: Fine. Got the hint. I removed all the Vallejo putty and replaced it with the 3M putty.
Since the driver of this build is to attach the upper hull, I added the screen to the rear of the engine compartment while I was waiting for the (CORRECT) putty to cure:
Time to address the glue bobble. I masked it off from the surrounding plastic:
I started sanding out the glue splotch with 320 grit, then went through the grits of 400, 600, 1200, and 2000 and finished off with Novus #2 Plastic Polish. If one knows where to look (and looks very closely) there is a very slight haze at the repair site. I will be surprised if anyone ever notices it:
With the putty cured, the area was masked again and it was filed and sanded:
I forget what I was painting (this from the person who can get up to go get something and forget what he got up for before leaving the room he’s in) but I had OD Green in the airbrush cup. I decided to use that as a primer to see how well I did blending the putty between two surfaces. My efforts can be summed up in one word.
Time for more putty, more drying time:
While the putty was curing, I added Grandt Line bolts and the locking pins to the gas cap covers:
I also checked the exhaust tips of the auxiliary generator. The kit molded them as solid stubs. I found a piece of .020″ (.508mm) copper tubing that the Eyecrometer said would work, drilled out each end of the tubing to a more scale thickness, and then cut off each end of the tube. They were aligned and glued in place:
With the putty completely cured, this time there was more filing than sanding. Files have flat surfaces so I decided to use that property. And since I had pretty much bollixed up much of the added weld seam of the glacis, I replaced that as well:
This time I had flat black in the airbrush cup so I primed the hull side again and this is when I (finally) realized that the depression I’d scraped into the side was of inconsistent depth. A wee bit of jiggery-pokery (evident at the left side of the clear panel) was required to get things to look like they were properly fit:
There are actually lights inside a Sherman so that the crew can see what they’re about with the hatches closed. The later lights have a changeable filter between clear and red (the latter to keep dark-adapted eyes dark-adapted), the early lights only have the clear. I decided that the demands of the day probably precluded mechanics from upgrading bits that weren’t essential…such as interior lights. I found a reference photo that I could pull dimensions from and scratch-built one:
I can scratch-build one. I can scratch-build multiple copies. I just cannot seem to build the copies as easily (or as well) as I could the first one. So the one in the photo above is the first one…and I used silicone molding putty to make copies of this one. This is what I used and it’s available from Michael’s (at least in the US):
Mix equal weights of A and B, WORK QUICKLY because this stuff sets up quickly, and in 15 minutes there’s a mold. Since I need three lights, I made three molds and filled them with resin:
I wasn’t thrilled with how the casting on the left in the above photo turned out so I didn’t use it, I used the master instead. The pour stubs were cut off and 0.010″ (.254mm) solder used as toggle switches:
Time to add them to the crew compartment in front (two of them) and the turret roof (one, obviously). Of course I wanted to put them in the correct places, so I spent a couple of fruitless hours online looking for a photo of where they should go. Fine. I’ll guesstimate and put them where I would want them (and it wasn’t until I had the upper hull WAY past the point of removal before I found a photo…because I was looking for something else, of course…showing where they went) (I like where I have ’em better):
I was curious as to what the exhaust tips I made would hook up with so I dry-fit the upper hull to see what’s underneath them. As it turns out, there are two Mystery Objects molded onto the bulkhead directly underneath the exhaust tips’ location. So once again I guesstimated that these Mystery Objects were part of the exhaust pipes and added 0.20″ (.508mm) solder to represent them:
It was shortly after I redid the interior paint (flat black with flat white misted over it) that I found the correct location of these lights. Having decided to leave them, once the paint was redone I used a toothpick I’d carved a chisel tip onto to scrape away the paint on the area I want clear (it’s just easier than trying to mask something so small…I do the same thing with landing lights and periscopes):
Adding the .30 caliber (7.62mm) machine gun will be much easier with the upper hull unattached. I painted the receiver my custom gunmetal (Tamiya X-18 Semi-Gloss Black 5 parts, XF-20 Medium Gray 4 parts) and added the Master GM-35-004 Brass Machine Gun Barrels that I colored using Birchwood Casey Brass Black Metal Finish (BRILLIANT stuff, that):
Then it was assembled:
No point in detailing the receiver because where it’s located the details won’t be seen.
With the upper hull still free, it was time to fit the turret to it. I’d checked the parts earlier and knew that they would need work to fit. These are the parts that have to play nice with each other:
They also have to play nice with other parts, as in, fit:
I can make that happen:
I also need to graft the bustle bottom to this part. It starts with tracing where I need to make the cut:
Then doing the fitting:
Fiddly but doable:
Tamiya used to mold the pistol port as an applique without the option to be opened. When I did the M4A3, I used silicone molding putty to copy the detail of the opening from a Dragon turret I have in my spare parts inventory. This enabled me to open Tamiya’s pistol ports with a bit of grafting, some putty, and cutting a hole. The resin copy was put back into the mold so that I could support it while I ground away resin to make this thinner. If I had tried to hold it in my hand to grind it, the warmth of my hands would have made the resin too flexible:
Once it was glued into place (but before the putty), I discovered that I’d misaligned it. It was easier to modify the hole than to try to pry the putty up (and have the resin part even survive):
While the putty around the pistol port cured, I worked on the shelf the radio inhabits. The radio I want to use is resin, making it heavier than a plastic part is. I thought the PE shelf was too thin and that using 0.010″ (.254mm) styrene as a replacement would allow the weight of the resin to result in the shelf drooping (I assume). Instead I used the PE part to create a heavy stock paper template and then transferred that to 0.010″ (.254mm) copper shim stock. Dry-fitting showed that the shelf wouldn’t sit level, so I used a scrap of 0.010″ (.254mm) styrene to fix that:
Once the resin cured, I masked over the clear panel and filed and sanded it to a precise (relatively speaking) fit:
All that sanding removed the as-cast texture which I replaced with Mr. Surfacer 500. A thin coat was put down with a disposable nylon brush and then the texture was replicated by stippling the surface with the flat tip of the brush:
And since the inside of the turret was never intended by Tamiya to be seen, it also got a Mr. Surfacer treatment:
I primed the clear panel on the outside of the turret with flat black. I didn’t mask the clear because the tape doesn’t stick well to it, planning instead to remove the paint with denatured alcohol and a chisel-tipped toothpick after the OD Green is shot. The priming shows where there are still some little gaps:
While I was here, I masked the interior of the clear part. Yes, the tape doesn’t stick very well, but it sticks well enough when tape is put in place where it will not be handled. Then denatured alcohol took off the exterior paint (easily, which is why I use it to remove paint, clean brushes, and clean the airbrush) and putty was laid down:
Mr. Surfacer replaced the texture that was sanded (and polished, of course) away:
Reapplication of primer shows that it all worked:
Before the upper hull can be attached, the .30 caliber (7.62mm) is attached:
These are about 99% of the parts that comprise the interior of the turret:
And this is what I’m replacing the kit parts with:
I started with the loader’s and commander’s seats. The commander’s seat is on a track that enables it to be moved up and down. Both seats also fold down (even though the directions of the AM set show them folding up) which enable the commander to have just the top of his head (at about eye level…go figure) exposed and folding down the loader’s seat gives him more room to maneuver during a fight:
The shortcomings of the Sherman’s design became evident in North Africa and emphasized during the Italian campaign. An interim measure, called “the blitz program”, was instituted to address some of these shortcomings without having to halt production to do so. This program added armor over the outside of the hull’s sides to add protection for the ammunition storage (the location of which is why a Sherman would explode and burn, not because they were gasoline powered), added armor to the turret in front of the gunner’s position, and angled plates in front of the driver and co-driver’s hatch hoods. These kits were also provided to be added at depots to upgrade tanks already deployed. Part of the blitz program was to address ill-conceived stowage of ready rounds along the periphery of the turret basket. A penetrating shot would cause the rounds to fracture, igniting the propellant, which would then lead to a catastrophic ammunition fire and explosion. The ready rounds were removed from the turret basket.
The resin AM part shows where the base of the shell would rest. Since I’m doing a “Normandy Sherman,” something that would have had the blitz upgrade, I removed those shell rests:
It was at this point that I realized that there really wasn’t anything stopping me, now, from marrying the upper hull to the lower hull. Dry-fitting showed me that there would be A LOT of tweaking and fitting necessary to get these two parts successfully mated. I went, literally, inch by inch. Fit, clamp, glue, go back to the turret basket. There was much rinse and repeating with that (made so much easier by the fact that little of the upper hull was parallel with the sponson bottoms):
Back at the turret basket, that all started with attaching the frame supports to the basket floor:
There were things that had to be added to the basket, much of which had to be assembled (and detailed, of course). This is the gunners turret control unit:
Most of which is there. One part failed to pour and it was the gunner’s control handle which was used to traverse the turret. So I had to make one. I used a piece, a very small piece, of resin from a pour block to carve it to size and shape:
And before that got lost, I glued it in place (the directions are also incorrect with this part…they show this part as upside down as well):
Lots of things were added to the turret basket:
One of the things was a bit or PE that whoever laid this thing out GOT WRONG. There are 9 folds that have to be made. Two of them are attached poorly from the factory. This photo is from the AM set’s directions. Part 10 is poorly, ROTTENLY, laid out:
Between the two larger areas to the right and left, the center part has a large “U” shaped opening. The two larger areas on either side of it are connected to it by ONE TINY POINT on each side. Well, freaking, DUH, you sodding beefwit!! Rotate those two larger areas on either side 90 degrees. Doing it that way would have allowed a much LARGER area to connect those sides to the central part THAT HOLDS THIS WHOLE DAMNED THING TOGETHER. (I suppose it’s…heartening…to see that a beefwit that failed out of engineering school can still find work in the field.)
Fine. This is what they gave me to work with. Fine. FINE. I’ll fornicating work with it, then. I started folding and all was looking good until the last fold (of course). I had an errant hand twitch while hold this thing. (Next person who tries to float this whole “age is just a number” bullshit will be at the receiving end of another “errant” nerve twitch involving my elbow and their solar plexus.) Anyway, the damned thing tore:
And that was the end of that day at the bench!
The next day I’d figured out a fix. A small piece of .005″ (.127mm) copper shim stock, bent 90 degrees, and glued in to serve as a larger anchor point (shown braced to a small machinist’s square to ensure that it is IN FACT at 90 degrees,with the part attached to the resin plate underneath it with double-sided tape to hold it in place):
And while I was in the process of doing that, I realized that just because the other side hadn’t ripped free, there wasn’t any chance that it wouldn’t rip free, so let’s fix that before it also breaks:
Then not only did I glue it together and attach it to the basket’s bottom…:
…the whole thing had to be done again because while using a hairdryer to warm the resin posts so I could position them correctly, it slipped out of my fingers and fell. Yep…it landed right on the PE part I’d repaired and came off the basket floor and apart from itself. So I got to do it all again.
[So. Do you remember the quiz I’d mentioned earlier? That whole thing about realizing something a bit…late? Here’s where I realized it! This turret basket being of early construction has screened sides. They block the view. In fact, the whole turret basket is going to block the view through the clear panel in the side. Well, well…talk about not thinking something through…sort of like the clear panel in the turret. Being unable to get both sides of that panel parallel, the sodding thing acts like a lens which distorts the view. Lessons learned.]
Clamping proceeded throughout all the above Modeling Magick:
This process was approximate. It quickly became obvious that the best I could get out of this process was a closer approximation of alignment. It wasn’t going to end up being correct. The gaps between the sponson bottoms and bottom of the hull sides was between 0.005″ (127mm) and 0.035″ (.890mm). Most of the sponson bottoms are resin, the extensions at their rear are styrene. To fit scrap styrene into the gaps between resin and plastic required me to glue the scrap to the inside of the hull sides using styrene cement and between the scrap(s) and resin with superglue. Then the clamps were removed, repositioned, and the whole thing done again. And again. Each side required four clamping sessions. This is the first side in process:
I remembered to take photos of the second side to show what I was dealing (successfully!) with. Gaps and a razor blade to apply pressure to the outer side where the scrap is pressed against the hull:
A better look at this gap (the other side was worse, if y’can believe that):
Not only were the sides out of alignment laterally, they were also out of alignment vertically:
Clamping under significant pressure (I figure when the thing starts creaking it’s time to stop adding more pressure) and lots of filing (filed because the surface is supposed to be flat and a file’s face is flat), and several sequential applications of putty along the entire lengths gets to this:
The sponson bottoms are supposed to be at 90 degrees to the lower hull sides. They aren’t. The sponson bottoms are supposed to be flat. They aren’t. But they look as if they are, and this is now before any application of paint. Both the lower hull and the sponson bottoms will be mostly flat black with a very faint misting of OD Green. Suspension, bogies, road-wheels, and tracks will fill most of that space. The end result (which is the goal, remember) will be that the sponson bottoms will look like they’re at 90 degrees to the hull bottom’s sides and look like they’re flat.
And that’s what Modeling Magick really is…making something look like something it won’t ever be.
M4 (Tamiya) Build #6 – Finishing the Engine, Engine Bay, and Discovering That Another Clever Idea for the Turret Simply Will Not Work, and Then Figuring Out What to do Instead
One thing modelers should get used to is after developing a build plan, being able to modify or abandon that plan selectively when events show that the original intent is just a dumb idea or simply cannot work. When I fitted the rear engine access hatches, I got the clever notion (proving that once again perfection eludes me) to have these doors operational. So I did that. Having done the work and spent the time to do that, I then decided that “operational features” is a 60s gimmick that I shouldn’t do. In the following photos, the hatches (which I wish I’d seen weren’t exactly accurate before I superglued the hinge pins in place) aren’t quite accurate. But, having already pulled that trigger, I dug out my Big Boy Knickers, donned them, and kept going:
Once the hull is painted, I’ll glue these hatches open. I’m leaving them as they are for now because though putting masking tape on the inside to keep the OD Green off the engine could be done now while this subassembly isn’t attached, getting the tape out once the part is glued on and the exterior is painted would create a problem I don’t care to deal with. So once it’s painted, these hatches will be glued open and bugger the “operational feature.”
Before gluing the engine in, I added stains and wear using pastels, enamel washes (supplied from the bottle of contaminated thinner I keep for just this purpose for its glad-I-don’t-have-to-match-this-color hue). Some of the wear was done with Humbrol Steel, some with silver pencil.
It’s at this point that the engine is glued in. There are more bits to add, but having the engine out where these bits are exposed would mean that they’d break, I’d do a lot of cursing, and they would have to be repaired and reattached…often. Gluing the engine in place now will create new challenges but the new challenges will be easier to surmount than riding the install-break-fix-break-fix carousel while my blood pressure spikes. Glue the this thing in (FINALLY) now:
There a several really small, thin, DELICATE, lines and hoses that get added now before the rear hull is glued on. (Later there will be more bits added that require the rear hull to be in place first…and my goodness ain’t I looking forward to that!) This little…gem…is comprised of three STD parts (no, not a dose of spirochetes but small-thin-delicate), one of which had broken (and fixed…twice) before I even removed it from the sprue. And since each part needed the two other parts in place before it could be added…where the hell to start?! (This is one of those times when four hands…all under my direct “control,” would have made this quicker and a lot easier):
While I was waiting for glue to set up, I adjusted the carburetor intake ducting to meet with the air filter housings. I was very surprised at how close they did match, though some bending (with the requisite entreaties to My Big Friend in the Sky) (known as “prayer” to you believers). Once I had them as I wanted them, I glued the ducting to the carburetor (the rear plate to which the air filters are attached to is just held in place with tape because this is the opening salvo of what turned out to be several days worth of work):
The exhausts and mufflers are prominent features in radial engined Shermans (and derivatives that also used the radial engine) and sit directly under the access hatch. Fortunately, styrene tubing of 1/8″ (3.18mm) is a perfect match for the diameter of the exhaust manifolds. I used a couple of lengths for that, relying on my Mk I Eyecrometer for length. As subsequent work showed, it’s spot on (a novelty I found refreshing):
Around these tubes I needed more tubing for the mufflers. What would be perfect is if I had a tubing that would just slip over these so that I didn’t have to go through the machining process to get the parts accurate. I was most pleasantly surprised to find out that 3/16″ (4.76mm) worked if I drilled out the center to allow sufficient room to slide over the smaller tubes. I attached the smaller tubing to the manifolds temporarily with white glue:
Dry-fitting the upper hull showed me that there is a large opening between the top of the rear hull and the underside of the upper hull. Well…ain’t that interesting. The question became, what the hell did they use to fill that gap? Many fruitless hours were spent online trying to find a reference photo. Okay…fine. What would I use to fill that gap? (That gap has to be filled. It’s large enough that an enemy infantryman could easily drop a hot grenade into the engine bay and that’s never a good thing for the tank or its crew.) I decided that I would extend the rear armor up to contact the upper armor, but that’s not what was done. Okay, let’s use a piece of PE screen, with cutouts for the air intake ducts and the exhaust pipes:
At this point I decided to dry-fit it and see how it fit…which it did not. The air filter housings plug up both sides of that gap. ::bangs head on desk:: Okay, let’s use a template this time:
And that seemed to work fine (please note “seemed to”…):
I don’t remember why I was online looking at M4s (maybe because I was building one…I don’t know) but I found a photo, a lousy photo, but a photo nonetheless, of that area of a Sherman and how about that! There’s a screen there! Since every silver lining has a dark cloud wrapped around it, the dark cloud in this case was the orientation of said screen. As you have seen, I oriented my notion vertically. ::sound of raucous buzzer:: Nope. That screen is supposed to be horizontal. (More banging head on workbench followed.) So I made another one, using Archer’s resin rivet heads (not that anyone will freaking notice, y’know) on the added plastic strip:
The screen goes under the mufflers with just the turned-down exhaust tips protruding beyond it. That will require me to cut the opening for them, but that’s a task for later on.
The next task, because finishing the engine bay is the driver, now, is making both intake ducts for the air filter housings. Those ducts look like they were constructed in the same manner that home clothes dryer vent ducts are; spiral wrapped with something that looks like fabric. Yes, I’m pretty sure it wasn’t fabric (heat, petrochemicals, etc.) but that’s what it looks like so that’s what I set out to replicate.
I started with more 3/16″ (4.76mm) tubing and bent them using heat (and anatomically impossible threats). Only having two hands, sometimes one must be creative about holding something in place to be able to mark it:
Having accomplished that seemingly impossible task (which could be any modeler’s epitaph), it was time for the application of heat. It took a couple of tries for me to consider using the tubing’s propensity for straightening out (don’t ask me how I found out that you canNOT anneal a styrene tube) in my favor by bending it seemingly too far, applying heat (another thing I’d rather you did not ask was how I figured out to use tape to hold it…but don’t worry, as if you would, the blisters are just about completely healed), and letting it cool resulted in just the amount of curve I was after (also…use a hairdrier, NOT a heat gun):
With the blanks formed (and all the melted styrene off the bench, floor, AND MY LAP cleaned up), I used 22awg wire for the spiral wrap. If you try this method, use a drop of superglue for each loop and then you can run a bead of superglue the length of the wire (this time I annealed the wire after I rediscovered that the wire won’t stay wrapped long enough for the superglue to even be applied):
With the spiral in place, I cut textureless paper towel into a strip. For the first one, I applied diluted white glue after I’d wrapped the paper towel around it. For the second one, I applied the diluted white glue with a brush as I was doing the wrap. The second method is MUCH easier and resulted in a better looking finish (these photos are from the first one I did):
A hairdrier dried them quite quickly (and didn’t result in more puddles…with paper…needing to be scraped off anything). You can see the difference between the first, awkward, method and the second, much cleaner, method. The first one is on the left:
With the glue dry, I used my “gun metal” paint mix, Tamiya X-18 Semi-Gloss Black (5 parts) and Tamiya XF-20 Medium Gray (4 parts), to paint them:
I set those parts to the side and went back to the tedium of gluing the STD lines back together. Sometimes one must get inventive aligning things:
And you can see below how well that didn’t work:
So I tried again, this time off the sprue:
It worked about as well as the first attempt didn’t:
So why did I waste so much time on this minutia? Because I liked the fittings that were molded onto these STDs. By the time I got to the point where I realized using these parts wasn’t going to work, I realized that I should have just used solder and replace them all…which is what I ended up doing. Near the top right of the photo below, you can also see where I added the tips of the fire suppression system:
Earlier variants of the Continental R975 had a breather/filler cap sticking up from the top of the crankcase. I forget where I’d read it, but after about 200 hours these engines were pulled out and replaced. I figured by the Normandy Invasion (the parameters of this build), the original engine would have been several engines ago. So I modeled this engine after a later variant. Instead of the breather neck, later engines had PCV lines between the air intakes and the crankcase. Those lines can be seen below as copper lines. Once I had the PCV lines in, I added the air intake ducts to the air filter housings:
The cat’s cradle lines assembly that needed four hands to do easily was added as were two descending lines to the left, and I mixed ivory black and white oil paints to create a color used to dry-brush the highlights onto the engine (which you can also see in the previous two pictures, just not quite so evidently):
I again wanted to see how much of the engine would show with the hinged engine cover open. Not much. But I know that at some point at least one person will take out their flashlight, bend down nervously close (for me), and look under the bolted-down engine cover:
Now that most of the engine parts have been added, it was time to add the exhausts pipes and mufflers. References have shown me that the mufflers seemed to rust more than the pipes leading into them were. I wanted to add the rough texture to the mufflers that I have seen while spending far too many hours on my back under a car wondering what broke (and wishing I could afford to have someone else under there instead of me). I wanted to coat the mufflers with superglue and roll them in baking soda. I really don’t like supergluing my fingers to each other (no matter how many times I manage to) so I made an armature/axle from a solid 18awg wire, rolled the mufflers in a puddle of superglue, and then rolled the gluey mass in baking soda. It’s not evident but at the top of the aluminum foil I used as my pallet there’s a puddle of superglue with the baking soda below it in the photo:
It was at this point that I realized that the two rings that go on each muffler had been forgotten. I used solder (I forget what size) to add them. The ends of the exhaust manifolds that these will attach to aren’t exactly square which required me to trim the smaller tubing to fit properly. So that I got these added correctly, I marked the top of each one with an “L” on the bottom of the one that doesn’t go on the right:
I used Italeri Flat Rust #4675AP thinned to something substantially less than the putty-like viscosity it came with and used a brush to apply it (because after wrestling with the Vallejo Aged White, I didn’t feel like cleaning my airbrush for another hour). It looked good before it dried, whereupon it became more red than I wanted. I’ll mute that color with pastels later after I’m done handling things. After this photo was taken, I painted the pipes before the mufflers Tamiya X-18 Semi-Gloss Black:
I used the jeweler’s tweezers (self-locking and on a pedestal) to align the exhausts and hold them in place while the glue set up. The second photo below shows how RED these things turned out:
After the exhausts were set, I added the exhaust tips. I was pleased that the fishtail exhaust tips that came with the kit were good enough to use without much modification. They were molded with the intent that they would be glued to the underside of the upper hull where it overhangs the rear armor plate (and y’know…Tamiya never did supply a part to deal with the gap where there’s supposed to be a screen…but then again, they also didn’t supply any sponson bottoms, either). I cut them apart, removed the mounting stubs where they would glue to the underside of the upper hull, and after testing for fit relative to the upper hull (just right), glued them to the ends of the mufflers:
And with that, I think that I’ve done everything I needed to do to the fighting compartment and engine bay! ::trumpet fanfare:: Next I puttied and blended the additions to the rear ends of the sponson bottoms, and spent a LOT of time getting the upper hull fitted to the lower. I got it as close as I could manage without destroying everything. It’s close. When it comes time to permanently attach the upper hull, I can see I’m going to have to get creative with clamps. But that’s a headache for another time.
The next headache is the turret.
My usual build order is to attach the upper hull to the lower at this point. But have you forgotten I want to add clear sections to this? The upper hull will have the clear section on the right side and the turret will have the clear section on the left side. I figure inserting a flat piece of clear styrene will by much easier than doing the same thing to the left side of the turret. Since this was the challenging part that I wasn’t sure how to do (not having done something like this before), I wanted to work on the deal-breaker that failing to pull this off would be. Masking the clear turret to leave a portion of it unpainted would be sort of tedious. I had NO idea how funny that notion was.
I found out.
The turret as it was delivered:
And of course I had a clever plan! I had intended to delineate the section that was to be clear. My first warning that Loki and Eris had…again…involved Themselves in my plans was when I had a difficult time even getting the Sharpie to stick to the turret:
Plan A was to cut out an area of the turret, fit it snugly to replace the kerf (that’s the slot a saw leaves behind as it cuts…sawdust has to come from someplace), and then use that as the buck to vacuform a piece of clear styrene to replace what I’d cut out. Lots of tedious and fiddly work. That gave rise to Plan B.
For Plan B, I was going to polish masked off the area inside the outline on the clear turret, paint everything but that area, and bam…clear panel in the turret without any fiddling involved and still a PERFECT fit.
I have tape. I have regular, tan, masking tape, blue painter’s tape, duct tape, 200mph duct tape, house sheathing tape, packing tape, electrical tape, and of course Tamiya tape. I wish I had as much money as I have tape. Well…that was before I tried masking that outline. It wasn’t as if it just slid off, but just about! NOTHING stuck to it. Nothing. It would simply move (or fall off) if I so much as touched it. Cut it? BWA hah hah hah. Well, if I can’t mask it, that torpedoes Plan B. Looks like Plan A it will be.
It was much easier to make the outline on the kit’s turret:
Even if I did bobble the cut a bit. (I haven’t used a coping saw since 1994.) You can see on top right of the cut where I missed the line:
I used a different saw to cut away the part I’d left behind during the bobble and glued it back where it belonged, and then started playing styrene scrap Tetris to refit the plug I’d just cut away. Once I had that done, I added little wings to increase the strength of the gluing process:
Since the inner edges of the hole would be visible, I needed to thin the plastic to scale thickness. As it was, that’s about 6 scale inches (152.4mm) thick:
The armor on top of the turret was 1 1/8″ (about 25.58mm) thick, so I kept at it until it was the correct thickness (yes, I have a 1/35 scale ruler):
The sides of the Sherman’s turret were about 2″ (about 50.8mm) thick, so I thinned the sides to the correct scale thickness while I was in a plastic-scraping mood. With that done, I set about setting the buck on the vacuum molder:
The thickest sheet styrene I could find is .015″ (0.381mm) so that’s what I used:
When I cut the plastic from around the buck, the wheels didn’t exactly come off the cart, but they were wobbling like crazy:
When the wheels come off the cart, the cart becomes a really poor sled. This is where that happened:
I’m sure you can see how thin that clear part is. Since I just had to know, I took out the digital calipers and tried measuring the thinnest section. My calipers will not measure anything smaller than 0.001″ (0.0254mm). Only one point measured that thick, everything else read 0.000″ (approximately 0.000mm). Yeah. Right. That’s going to give me a lot of gluing surface, not to mention great resistance to any pressure against it (sarcasm…probably the most used service I don’t just offer, I insist upon). Those of you who are old enough to remember cellophane know how thick this part wasn’t.
Hmmm…Plan A ain’t off to a stellar start, methinks. That’s when Plan B-1 arose. CUT WHAT I NEED FROM THE CLEAR RESIN TURRET!
All I can say (no…not really, there’s lots I could say) is Plan B-1 was a pain in the ass. Righteously so. But if I couldn’t get the clear section into the turret, there would be no clear sections at all, and dammit I want clear sections.
This time I didn’t use the coping saw. I made a bazillion shallow passes with the smallest burr I have for the dental drill. To accomplish that, I used white glue to attempt to attach the cellophane part to the surface of the clear turret. This is when I found out that there a subtle difference between the curvature of the clear, donor, turret and the intended recipient of the transplant, the kit’s turret. You can see where the white glue failed to harden even though it sat all night to do just that:
Knowing when to quit is still an arcane skill I’ve yet to even become conversant with; forget mastering it:
Then came the fitting process. I spent took two days to get to this point. Since I just mentioned it above, you’d better remember…er…I’m sure you remember when I said that the shapes were subtly different? The gaps below…after taking two days…are the best I could do with it at this point:
Gaps can be adjusted and filled, resin can be heated and recurved. But it’s all for naught unless it’s clear, so the grinding, sanding, and polishing commenced. Resin doesn’t melt as plastic does which allowed me to use a Dremel for the initial shaping. Files followed. Then I started with 220 grit sandpaper, to 320, 400, 600, 1200, and 2000 grit:
I was just about to go to Novus #2 plastic polish when I saw this little tiny scratch; tiny but deep, requiring me to go back to 320 grit to excise it (the needle tip is pointing at it):
It was at this point that I tried fitting the clear plug to the turret. No, resin doesn’t melt like styrene does. As I have just learned, this resin became warm enough to change its shape:
I decided after a few days of this, I needed a break. Behind the clear plug above, you can see a U-shaped depression. This is where the pistol port goes. Tamiya never thought anyone would need it open so the pistol port itself is a single piece. As ever, I have other plans.
When I did the M4A3, I encountered the identical situation with its pistol port. My solution was to take a surface mold of a Dragon turret that was not only molded open, it had the correct flange around the opening. I still have the surface mold and I tend to try to use the left over resin whenever I do a pour and I had cast a pair of pistol ports from that mold. I used one of them here.
I’m familiar with the physical properties of the resin I use (Smooth-On’s Smooth-Cast 322, a polyurethane compound). It becomes very flexible from just the warmth of my fingers which renders it quite flexible. This is a small, thin part, and I knew that it would be challenging to thin it out enough. I put the casting back into the mold so that my hands wouldn’t warm it and the entire surface of the casting would be supported before I used the Dremel with a burr to thin it out as much as I thought practical. Since the turret has no opening for the port, I held the part in place, traced the opening onto the turret with a pencil, and then cut a hole for the port. I checked alignment by dry-fitting the casting. It works:
Frankly, I was never content with the area I’d thought to make clear, it just took me a bit to figure out what I didn’t like about it. I didn’t like the area on the top of the turret. What that area would allow seen can be seen through the commander’s hatch. Being an earlier turret without a loader’s hatch, this turret didn’t come from the factory with the vision cupola seen on later versions (though they were frequently fitted in the field), it had the old split hatch which allows a larger view of the turret’s innards. I made my decision, cut the opaque plastic from the buck, and refitted it to the turret. Having thinned out the periphery of the roof opening, I filled the resultant depressions with 0.010″ (0.254mm) scraps and then 3M’s Acrylic Putty (the deformed plastic near the opening was where I had glued the plug to a bit of styrene tube to support it on the vacuum molder’s platen):
Then I puttied the outside:
I like this opening much better.
Since the opening is smaller, the clear plug had to be as well:
After letting the putty sit overnight, I scraped it down. Sanding it would make the surface too smooth. These things came from the factory with very little, if any, finishing. Yes, scraping it would make it smoother than it should be, so I’ll try using the Mr. Surfacer 500 to replace the rough-cast surface texture:
That was the easier part, next was the interior. I scraped, sanded, and muttered imprecations and realized I would need another application of putty to fill in minor depressions (sort of what happens when I look at my checkbook balance, only without the “minor”):
Next month I hope to finish the installation of the clear plug. I consulted a fortune teller who told me that I have much polishing in my immediate future.
Next time I have my fortune told, I think I should consult someone who reads tea leaves instead of someone who reads my entrails. I just don’t have the guts to do that again.
M4 (Tamiya) Build #5 – Assembling the Lower Hull is Mostly Completed and then Painted, Stained, and Worn, the Upper Hull is Fitted, and I Finally Get to Fit the Engine Into the Lower Hull
What drives the build changes as things move from the “pending” category into the “all done” category. The driver of this build has now switched to what needs to be done to attach the upper hull to the lower hull. I started by detailing and reworking the engine bay access hatches on the rear hull. I removed the molded-on retaining strap and replaced it with .010″ (.254mm) copper ship stock. The grab handle was replaced using 22awg wire (the holes are drilled over the hatch to show me where I need to add bolt heads, the holes on the bent tabs stay vacant) and as of this post these hatches are intended to be operational:
Fitting the upper hull to the lower hull showed me there was a bit of work required to accomplish that. The first fit impediment was the box on the sponson next to the co-driver. It was too far forward and needed to be moved rearward:
Once that box was moved rearward until it was in contact with the ammo rack, that part of the hull settled down correctly.
While I was mucking about with the upper hull, now seemed to be a good time (or maybe just not a bad time) to decide exactly where I’m going to replace the opaque plastic with clear plastic. I lightly scribed the outline (the actual execution of this replacement has occupied many hours of skull-sweat this month) onto the hull:
Another question I’ve gotten is, “How do you know where the light falls?” Being lazy (and more than a little bit nuts), I figured out a simple way to do that. Use light. I used my cellphone (which is where these photos came from) to take a photo so that I can actually remember something for longer than five seconds:
I added oil lines between the oil cooler and oil reservoir using .020″ (.508mm) solder:
At this point I painted a few items that will need to be added once the “light splash” is added to the interior. The leather was distressed by using colored pencils and a wee bit of dry-brushing:
And since I had the latex gloves on anyway, I loaded the airbrush with Tamiya’s XF-2 Flat White and did the light splash effects:
Though recent Tamiya kits evidence excellent fit, t’weren’t always that way. Where the front mudguards “fit” the differential cover needed help. I added successive layers of .010″ (.254mm) styrene until I had more than enough and then sanded/filed them to a more correct fit:
I always try to add a pin-up to my armor models (the FT17 didn’t have one). This time it’s Jane (different Jane, Firefly fans):
And speaking of Tamiya, they made an excellent 75mm ammo set (#35191) that was beautifully machined out of brass (which takes care of what to paint the casings). For those of you this sort of minutia matters to, the shells with the silver stripe (and gun metal fuse housing, though that’s next to impossible to see) are HE (high explosive) and the shells with the solid OD green projectiles are AP (armor piercing). The only thing I did to these parts before painting them was a 20 minute bath in salted water to slightly oxidize the brass surfaces. To paint these things, instead of trying to mask off all those parts, I held each one by the shell casings (tweezers, obviously) and dipped the tips into a bottle of Tamiya XF-62 Olive drab (3 parts) and XF-2 Flat White (1 drop for scale color correction), and stuck the bases of the cases to double-sided tape affixed to thin cardboard to dry overnight. The next day, and completely unsurprisingly, I saw where I’d dipped some of them too deeply into the paint. Since acrylic paint doesn’t like to stick to metal bits, I used that characteristic and scraped away the overage with a fingernail. The next day I came back and applied Tamiya X-11 Chrome Silver with a brush. For the fuse casings I used my custom-mixed “gunmetal” of Tamiya X-18 Semi-Gloss Black (5 parts) and Tamiya XF-20 Medium Gray (4 parts):
And then they were added to the ammo racks. Some rounds fit snugly (almost too much so) and some required a tiny dab of superglue to stay in place. I kept some rounds to add later to the ready-racks in the turret (and aren’t those primers fantastic?!):
And then I added the auxiliary generator…Three hours of diddling, twisting, touching up paint, more diddling and twisting, until it FINALLY settled in where it goes:
With that little nightmare accomplished, I added the fire extinguishers, seats, and instrument panel.
So, in the last post I mentioned where I thinned out the opening around the engine bay to get “scale thickness.” What I got was another instance of where I over-clever myself into more work. On the M4/M4A1s, the sides of the engine bay come right up to and even with that opening. So that meant that once again, I over-clevered myself and did the work to fix my “cleverness” by adding scrap styrene and then finishing it down:
While that glue cured…completely… I sprayed lit areas with clear gloss and used a black wash using oil paint to pick out details. Then I used pastels, Humbrol #27003 Steel, and a sliver-colored pencil to add wear and staining. Since I am (attempting to) model a relatively newly-deployed tank, I did not weather and wear the interior to the same extent I did with my M4A3 (and also added the spare periscopes to the stowage box over the transmission):
There is another ammo bin next to the driver. Frankly, I can’t see how that bin could be opened without the forward door smacking the driver seat…and forget having enough room to get the round out. I also just don’t understand how the supplied parts could work…so I didn’t add them. The doors to the bin are closed and empty bins won’t show on that side (the other side that has the rounds in the racks are right where the clear panel will go so I added those there):
With the crew compartment populated, my attention turned to fitting the upper hull. If you look closely at the following picture, you’ll see where the forward bulkhead and both sides of the engine bay don’t meet the upper hull:
When I looked closer, I saw that this section of the upper hull really doesn’t fit. There are substantial gaps where there shouldn’t be gaps. First photo is with the flash, the second is backlit:
To fill that gap I used .030″ (.762mm) scrap styrene to start filling the gaps:
With the upper dimension of the added plastic in place, I added more of the same scrap to the sides:
At this point I wondered if I needed to add more plastic to the engine side of the bulkhead so I dropped the forward engine cover in place to see if that section would even be seen. It won’t be, so I didn’t bother:
A LOT of filing ensued before I achieved the effect I wanted. A trick I used that made this easier (relatively speaking) was using a flashlight to back-light the sides of the engine bay to see where the gaps were:
Finally. Fitting the engine. It had been awhile since I last checked the fit of the engine. So it was with no small amount of trepidation that I put the engine in place and dropped (again, all terms being relative) the upper hull in place, dry-fit the engine covers that will be in place, to see if it still fit:
YES! And the Sword of Damocles is returned unused to its celestial scabbard!
Before I could do more additions to the engine, I had to attach the rear mounting. Before I could do that, details had to be added, so details were added using .015″ (.381mm) solder:
Then I did the starter (on the left) using .025″ (.635mm) solder and the generator (same diameter solder):
And then I remembered that I had yet to paint the inside of the upper hull…which reminded me I still had a few bits to add before I could do that. Reference photos indicate that the fixed periscopes (no doubt in there to take the place of the direct-vision slots) weren’t fitted often, probably due to the periscopes in the hatches blocking any view out of the fixed ‘scopes. The now-closed-but-definitely-missed TMD offered the empty ‘scope mounts. Having a few of those on hand, I cleaned up and glued a couple in place. Also from TMD are the mushroom-shaped inner (passive) vents that were added:
To finish the inside of the upper hull, it was painted Tamiya XF-1 Flat Black and then Tamiya XF-2 Flat White was misted over that. Because the empty periscope mounts are easily visible from outside, and therefore in more direct light, I shot those from above and through the hatch openings:
While dealing with upper hull minutia, I added weld beads using Vallejo Acrylic Resin Putty #70.401 (which, if you need to apply weld beads is GREAT for doing that…best technique I’ve yet found to add weld beads) to the applique armor in front of the hatch hoods:
While I was in the let’s-add-weld-beads mood, I glued the rear engine cover in place and added weld beads to it and the sides of the rear applique armor where it joins the upper hull:
With all the additions to the engine bits done, the engine bay and associated parts were all hit with Tamiya XF-1 (with the exception of the generator and starter motor which were done with Tamiya X-18 Semi-Gloss Black to match the paint on the rest of the engine):
The rear engine mount was misted with Vallejo’s #71.132 Aged White. Once it had set up, the mount was glued to the engine. Once the glue set, I added the starter motor, generator, fuel pump, and carburetor and connected the “wires” where they could be connected and routed the ones that couldn’t be connected (because…where?) to where they would disappear into the dark engine bay. The hoses and wire insulation were painted with Tamiya XF-85 Rubber Black, with one wire being painted Vallejo’s Aged White:
I used Aged White again to “splash” light into the engine bay (and neglected to take any photos of that). I came back the next day to see if the engine still fit into the only space I have for it:
And yes…it does!
So. There. The engine is finally fit! Next post will (I hope) include where I glued it in and the remaining hoses and wires that still need to be added.
M4 (Tamiya) Build #4 – Assembling Bits for the Lower Hull Continues and I’m Reminded That Sometimes Things Work and Sometimes They Do Not
…and I still haven’t done any work fitting the engine. But I did continue work on the engine covers. I laid out where I have to add bolts later:
The air intake for the cooling fan is protected by an armored cover and a grill. With the armored cover close the grill isn’t evident. I made a blank to replace the grill:
I determined where the center of each piece is, aligned them, and glued them together:
I clamped the two parts together using reversed clothespins:
Setting that aside to cure, I realized that the upper hull over the engine was too thick for scale. Yes…I have a ruler in 1/35 scale…and no, the top of the hull over the engine was not 2″ (50.1mm) but more like 1″ (25.4mm):
Rather than trying to reproduce the armored air intake cover, I cut the kit part off and used that instead. To start that process, I glued the cover onto the kit’s engine cover and then cut the rear mounts (which are actually hinges) free and then used .010″ (.254mm) scrap to replace the kerf.:
At this point I was still trying to make the hinges for the engine cover operational. I drilled out the rod to allow the hinge pins to seat and then glued the hinge parts to their respective locations:
I let those parts set overnight so that the glue was totally cured before I checked the hinges’ function. I didn’t have much faith that the hinge parts would hold given how incredibly small the contacts are between the hinges and plates…and that’s not even considering what operating them would do. I was correct, however. The hinges failed immediately:
And here the entire notion of “operable” is tossed. I dug through my spares for a pair of armored fuel cap covers (Dragon parts, I think, and substantially better than what Tamiya had molded on), glued them in place as well as the armored vent cover as well as adding the bolts that hold this panel down:
There are three panels that comprise the engine cover. The one I just finished making, the panel that hinges open for minor engine maintenance, and the rear-most panel which is welded on. The opening panel is bolted closed so I added a lip for it to bolt to using .005″ (.127mm) styrene and drilled the bolt holes (later on I added three bolts just laid on top of the rear-most panel):
A quick check (of many) to be certain everything fit as I wanted them to (and hopefully I was correct). I’ll add the cylinders for the hinges later:
With the distraction of hull work attended to, it was time to turn my efforts back towards getting things ready in the crew compartment. One of the things I had to do was to make a clevis to replace the one that got lost. I used a piece of resin pour block instead of styrene because of how flexible styrene can be. This is a really small part and I wasn’t confident that the plastic would hold up while I cut and whittled the shape I needed. Resin can also be flexible, particularly when warmed, but a quick dunk in cold water returns its rigidity. That process started with cutting a small piece of resin to work on:
Cut a slit to open up with my dental grinder:
And then started cutting and carving…using a VERY SHARP scalpel:
The part isn’t identical to the other, but it shouldn’t be noticeable once the part is in place (and nowhere near as noticeable as it’s absence):
There is a torque bar that is part of the clutch linkage. The resin shaft broke so that had to be replaced. I noticed that a paperclip was the same diameter so cut one and fit it as a replacement:
Last summer, I looked at CMK’s website to see if they had any more of these interior sets and they didn’t. That’s why I made copies of the one set that I had and why I’ve been trying to avoid using the PE that came with the set. But the next thing I had to make was provided for in this set in PE. It’s one thing copying a basic or simple shape on shim stock. It’s a different thing when the shape is neither simple nor basic. So four months after the last time I checked, I went back to CMK’s website to see if these sets were still being produced. Yes, they are! (Wish I’d known that before I spent more money than I care to mention on molding rubber.) Instead of making an inferior copy of the PE part, I used the PE part (now that I know I can get more):
With that bent and glued, I had all the subassemblies I needed to be able to check fitment. So I checked fitment. It all fits in much the same way an actual M4’s things fit. TIGHTLY:
When I’d extended the sponsons, I neglected to check at to why the sponsons were shorter. That’s because there are kit parts that provide the upper inner sides for the engine bay. After briefly kicking myself for a seeming error, I realized that I was going to have to add the sponson extensions anyway, though it probably would have been easier on me to add them later. So it goes. But that meant I had to get rid of the extra .030″ (.762mm) so that the sides, which are also supports for the rear upper hull, don’t stick up too high. Much carving and scraping ensued yet I prevailed. I thinned out the styrene I’d added to about .005″ (.127mm) and then added wire pins to the kit part. I’d intended on socketing them into the tub sides but totally bitched that one up. Then I reminded myself of what the pins are for. They’re there to provide structural strength and added gluing surface. Well, I can do that just using superglue…I don’t need the pins to fit plastic tightly, just that they’re held in place tightly. Superglue filled the void I cut out and that part is ON there permanently (the white circles are filled ejector pin sockets…Tamiya never expected this part of the model to be seen):
When I did the other side, I didn’t bother with pins at all:
The resin parts that extend the upper wall of the engine bay were too long. They were too long because someone out clevered himself. Again. I figured out where they’re supposed to end, marked them, and then cut them. And during dry-fitting, I realized that this part also didn’t count on having a layer of .030″ (.762mm) styrene in the way. This time, though, it was a much simpler shape and I could remove the excess from the bottom:
No, the resin parts didn’t fit well, probably because of how “clever” I was:
A bit of filing improved the fit:
Then I removed some of the bottom of it to dial (or file) in the fit and all gaps were filled with superglue and filed smooth:
What’s pushing the build at this point is getting things ready for the shadow-coat for pre-shading. In other words, paint things black. I don’t know how much of the rear of the engine bay will show through the open engine cover, but it’s SO much easier to “fix” now than later if I do need to fix it. I added the pintle mount and puttied all voids inside the rear plate:
When I extended the differential cover, I knew I was going to have to putty things and then put the texture of a roughly finished sand-casting back. This is my first time using Mr. Surfacer 500 and rather than put the build at risk, I found the same differential cover in my spares and tested it there:
Pleased with the outcome, figuring I can sand/scrape the surface into a closer approximation of a cast surface, I did it again on the build:
Sanding and scraping gave me the look I was after. And before I populated the sponsons with all sorts of fragile resin parts, I decided that while the sponsons were still bare I’d also add bolts to the bottom of the differential cover and the engine inspection cover:
Dry-stowage Shermans had their main gun ammunition in racks behind thinly armored sides. There are guides (and probably latches) on the ammo racks to hold the rounds securely in place. There are lots of those things in PE. I needed to bend those PE parts to an even and consistent curve. Friend of mine gave me the idea on how to jig them so that I could get the even and consistent curve I needed. It started here. The guide is on the penny and where that guide (and many others) needs to go is shown by one of the rack’s faces:
To make the jig, I used an empty casing from Tamiya’s #35191 Brass 75mm ammunition set. I used .040″ (1.016mm) styrene and cut the required hole in two of the styrene scraps. Then I cut across one of them. The uncut scrap had the casing inserted from underneath and the cut scrap was used as the ram to form the PE around the casing:
BEFORE even attempting to bend the PE I annealed them first (heat them up bright red and let them air cool at their own pace…makes bending PE much easier). Then I put a very slight bend in the PE, more to allow it to stand on its own than to shape it:
Then I centered the PE on the ram’s cut out and pressed it tightly against the casing, using tweezers to bend the wings completely around and snug against the casing:
Then result worked…and I only had to do it another 31 times:
And this is where the wheels came off this particular cart. Not only aligning the guides to the holes AND trying to keep the PE part on the resin and not stick to the needle I was using to transfer superglue, but to make them all the same:
Tedious. VERY TEDIOUS. After two hours I’d only glued three of the guides in place and they absolutely and totally sucked. Useless. I snapped the three off (that part was easy) and stuck them into the container. They now reside in my spares stock for perhaps future use.
Since I’d already cleaned up the resin parts of the ammunition racks, it was time to glue them to the sponsons. This is another instance where having four hands would have been useful. It took me some skull sweat to figure out how to even start, and I started with the inside wall of the bin:
I had three plates that all had to line up since I intend on using Tamiya’s ammo set. So I used three pieces of it as alignment dowels:
Worked well, mostly. If you look at the back plate (where the pointy ends of the ammunition points to), you’ll see that the back plate doesn’t come down far enough. I used a small piece of .020″ (.205mm) to bridge the gap:
Then I had to do that again for the forward ammo rack (which has a structural support for the weight of the turret above it…it’s the dark gray square part):
These parts are also for an ammunition rack. I have to say, though, that this makes less than no sense to me as you’ll see shortly:
With the doors (though I’ll bet they called them “hatches”) in place, and considering the location of the hinges (the center upright), every time the forward door was opened it would smack the driver in the face. Every time the rear door was opened, it would smack the driver in the back of the head. And this was just opening the doors. Wrestling a 75mm round out of there while the driver was seated would have resulted in someone getting a 75mm suppository:
The rack itself, the thing that’s supposed to hold 75mm shells in place, makes NO sense to me so I’m not adding it and will build this with these DUMBass doors closed.
The inside of the rear is now finished:
And most of the things that populate the sponsons in place (the instrument panel and auxiliary generator have to be painted before installation):
It’s time to get things ready to paint black. To keep things from being blown off the bench by the airbrush, I used double-sided tape to stick them to a piece of cardboard:
And then I sprayed Tamiya XF-1 Flat Black over everything. While the paint was curing, Panda Plastic’s T48 Rubber Chevron Worn Tracks arrived:
If you’re building something that uses the VVSS suspension of a Sherman, and individual track links are less desirable to you than a digital prostate examination, check out Panda Plastics tracks. I use them whenever I can. End of free endorsement.
Three days later I had 80 links assembled (yes…I’m “supposed to” only need 79 per side):
Yeah, so, sorry about these photos. Lousy light today so I used a flash and tried to adjust it in post. I’m not pleased with them but here’s where I am now, everything shadow-coated:
Maybe next month I’ll work on fitting the engine…
When I think of magick, I think it’s having the ability to think of something, support that thought (or plural) with ritualized actions, to bring about a very real manifestation of the something that had been thought of. And since you’re probably pretty clever, I’ll bet you’ve already hooked that to scale modeling. (I’m equally sure that finding this essay on a modeling site had nothing at all to do with connecting those dots.) Because that’s what modeling is for me (your mileage should vary)…seeing something in my head, sitting down at the
altar workbench, and eventually I find something that closely resembles what I’d seen months earlier in my mind. So where does the whole “black” thing come from?
Again, to my way of thinking, “black magick” is going through all of the visualization, actions, and manifestations but without a beneficial end in mind. Black magick is not just without a beneficial end, it’s with a disagreeable or unhelpful end. The incantation that creates the maleficent is a simple one:
Two words, five letters, and one apostrophe and it all (whichever particular “it” is in play) comes abruptly to a halt…which is where it generally stays. Two words, five letters, and one apostrophe and the person did it to themself. And whatever “it” was torpedoed stays torpedoed until the person who uttered the incantation undoes it.
Too often that incantation doesn’t get undone. We don’t miss what we never had, right? And since they couldn’t to start with, there’s nothing to really miss, right? Pick up the remote, go to the social media junkie of your addiction, and nobody will know, right?
Not right. You will know. You did it to yourself and will know that you STILL “can’t.” So, clever hominid that thou art, can y’guess how to undo the spell? It’s a long incantation but I’ll lay it out here anyway in case you’re one of those rare people who can boot their Ego out of the driver’s seat and take control:
Change your mind.
Thoughts are not subject to Newtonian physics. Thoughts have no mass so there is nothing impeding their start, stop, or any direction changes between those states. Essentially, we think what we think because that’s what we THINK. But there’s a codicil to all that.
You see what you see because you’re prepared to see it and you do not see what you miss because you are not prepared to see it. The subject of that sentence is what keeps priests, politicians, and stage magicians well-paid and with no shortage of work. It doesn’t have to be like that…and in fact isn’t like that. The only thing that keeps us plodding along the same traces is habit. The ladder to a habit is a short one and goes much like this…
“How the hell am I going to do this thing? I’ll try doing this thing this way.”
“Wow…that worked! I’ll do it that way the next time!”
“EXcellent! It worked just like the first time.”
“Hmm…well, I have to do this thing. I guess I’ll do it the way I’ve always done it.”
Welcome to your new habit and tradition. You forgot that it was “always” done only twice. But unless you change your mind, that’s how you’re going to do it in the future unless and until something drastic happens to change your mind. Should that happen, we will focus on what “caused” us to change our mind; those surprising circumstances. Uhm…no. The circumstances did not change your mind. You changed your mind and passed the responsibility for that change onto the circumstances.
So why the intercourse are you reading this on a modeling site, of all places?!
It’s because of the standard excuses I get from people who don’t engage in this hobby.
“I don’t have the patience.” Black Magick.
“I’m not any good at it.” Black Magick.
“I don’t see in detail the way you do.” Black Magick.
“I can’t use tools like you do.” Black Magick.
“I’m too old.” Black Magick.
“I’m too young.” Showoff.
“I have no idea how to do any of that.” Okay…that excuse has potential. It’s also accurate because unless a person has tried it, screwed it up, and fixed it up, they’re correct. They have no idea…but they could get one (or a bazillion).
A person needs a few things to be decent at this hobby.
Hmm…I can’t think of anything else so maybe there aren’t “a few things” at all! Does this stuff fascinate you? Would you like to be able to make decent, or maybe good, or heresy of heresies…EXCELLENT models? If you have the desire, then you have all the foundation you need to get on with it. Others more eloquent than I have talked about how to learn, that it’s our mistakes and oh-goddammit moments that offer us opportunities to expand our skill-set(s). (“Teachable moments” are not particularly comfortable moments, so stay at it.) To make those mistakes requires that one pats Ego on the head, leave it a comfy bankie in the sun to nap on, and go make some sodding mistakes. Doing a new thing correctly from the get-go teaches nothing. We don’t “learn how to do”something. We learn how to not “do something.” If we stay at it, keep learning how not to do something, eventually we will, WE WILL, arrive at the knowledge of how to do something. The really smart ones don’t seem to have to go down that path very far before The Clue arrives. People like me, the plodders, have to make EVERY MISTAKE POSSIBLE before we get The Clue. [Sidebar, here. People who figure things out quickly or who are “naturals” at a thing generally make really lousy teachers. They seem to make the assumption that because it was relatively easy for them, well it’s relatively easy! People like me who have to make every mistake possible tend to be better teachers. We know all the mistakes, know where all the cognitive mines are buried, can spot when someone goes haring off down the wrong path quickly and stop them before the flawed methodology becomes “tradition”, and nudge them onto a more productive path…all the while remembering how we learned and not getting between the student and the really formative mistake so that they learn, too. End of sidebar.]
I won’t hear your answer to this question, but really…y’gotta ask it of yourself. Do you really want to learn how to build scale models? Do you have the desire? Do you want to or do you want to want to? Can you forgive your present ignorance while you’re busy working to diminish it? (Modeler’s Secret here: If the model TOTALLY SUCKS…don’t show it to anyone.) Don’t sit in the bleachers wishing you were a Modeling Deity because if you talk to a Modeling Deity you will find that they don’t usually think they’re that good…which leads me to the next wall a person learning something will probably have fall on them.
Good judgement comes from surviving bad judgement. The recurring theme here is (in case you missed it or the hammer I’m beating that particular horse corpse with isn’t working well enough) if you don’t do it, what’s to judge? If you do it, then the only thing you need to survive your own judgement is self-forgiveness. You ain’t perfect, I certainly ain’t perfect, and anyone who presents themselves as perfect is an excellent example of who (and what) to avoid. No matter how much anyone learns, the really, really, really, REALLY big universe will always have more than one person can learn. Big universe. Small brain (which is different from being little-minded). No meaningful amount of the universe CAN fit into our tiny little brains…which means that regardless of what can be assimilated intellectually, when we run out of bandwidth we run into our own ignorance.
The only way to work against the ignorance and entropy is to learn something new. We’ll never Get There, which is why I think it’s so important to choose activities that we enjoy the simple doing of, regardless of how well we do them. Enjoying the activity for itself becomes the reward and will encourage a person to keep doing it. And that’s some sneaky shit right there. If the pleasure of doing a thing is sufficient (remember…don’t let Ego take control), we will keep doing that thing. And if we keep doing that thing, we will err. Make mistakes…and then fix them (talk about a compressed learning situation) and keep doing the thing. If you pay attention to what you are doing, “how” you are doing takes care of itself.
Get with that and you’ll really have to work to stay lousy at it…whatever “it” is.
So go buy a kit. Don’t spend a lot of money on it because you ARE going to bitch it up. Follow the instructions and put the thing together. Stay at it until it’s done. Put a cloth or box over it and walk away from it for a few days…then come back and look at it. Pick ONE THING to fix and buy another kit. Build the next kit and figure out how to fix the ONE THING from the first one. Repeat. Repeat a lot. (How many scales does a musician have to play before they can be considered “good”?) Each time you finish one, pick ONE THING to get better at. The goal is to build the kit straight from the box, make all the seams disappear, make all the glue fingerprints a thing of the past. Discover how tricky it can be to glue clear parts in place without totally buggering them.
The real secret to anything is to just stay at it.
And one day, you’ll build a kit that you will be surprised at. No seams, glue smears, evident mistakes (please note the word “evident”…I can show you all the mistakes on the few contest winners I made and on the ones I never entered a contest with), a decent paint job (don’t let airbrushes scare you…it’s just another tool). And the really big one:
NEVER BUY A TOOL UNLESS YOU HAVE A USE FOR IT.
All the modeling Gods that have come before us were born with the same thing we were born with. Other than the ability to know what a nipple is for, nothing. If they could do it, why not me? Why not you?
If you have the desire, then indulge. If you don’t, then don’t kid yourself and go find something you like to do just for the doing of it.
Tempus fugit. Comes the night that no one escapes. Do good work. Be kind. Be compassionate. Use a moisture filter with an airbrush. Keep your blades sharp. Challenge yourself. Don’t start a kit you know how to finish (unless it’s a commission). Don’t mess around with old people. They didn’t get old by accident (people die young by accident all the time) and “life sentence” is less a deterrent the older one gets.
M4 (Tamiya) Build #3 – Assembling Bits for the Lower Hull Continues and I Ponder Tamiya’s Willingness to Utterly Ignore the Underside of Things
Where the AM sponsons attached was treated with 3M’s Acrylic Putty (because this was during Tamiya’s “Nobody will ever see under here” phase and didn’t bother to include sponson bottoms with the kit). The sponsons were welded and I’ve not seen any seam here so that gets puttied:
And Tamiya’s utter disregard for anything underneath the model continues to…well…anything underneath the model. Asuka has a good reputation for accuracy and detail (among other traits) so I took one of their DV (Direct Vision…Shermans originally came out of the factory with vision slits for both driver and co-driver) Shermans off the shelf and used the underside of that kit as my source for details and measurements, transferring locations from Asuka who has them onto Tamiya who does not. I know…it looks like the Asuka hull bottom is much shorter but that’s an illusion. The Asuka bottom is a flat piece without sides and it’s far enough from the camera lens to create that illusion. I used a divider (like a compass but with two steel points instead of one steel point and pencil lead) to mark where things are going to go:
Tamiya ends the differential cover too soon at the underside. I extended the underside of it using .020″ (.508mm) flat styrene. Once the glue sets up completely I’ll fair the forward edge the forward edge of the plastic I just added to blend it with the differential cover:
I punched out the appropriately sized discs to use for the drains (which are what those round bits on the bottom are). When I have to center a disc over markings, being able to see the markings makes things much easier (and accurate). To enable this, I punch out the first disc…the one that locates however many will follow it…out of clear styrene:
I wanted to add the lower engine access cover and escape hatch. With the locations marked, I drilled the corners of the intended openings to provide the rounded corners:
And right after I had all the holes drilled, I realized that the lower engine cover wasn’t recessed from underneath; it bolts into position and drops down when it’s unbolted. ::sigh:: I don’t know if those mistakenly drilled holes will be evident once the engine and upper hull are in place, but I do know that plugging those holes will be easier now than later. I took a piece of sprue from my extensive (and like the rest of us, growing) sprue stock, chucked it into a variable speed drill, and sanded and filed it to a taper so that I can glue it tightly into place(s):
And then it’s trim, file, sand, and putty where needed:
I also had to redo a couple of the saw holes for the escape hatch (switching to tea…which unfortunately has less caffeine than the kidney-flush coffee I make) (made):
The thickness of the plastic in this area is MUCH thicker, scale-wise, than it ever was on the actual Sherman:
I think it was something like an inch and a half (about 38.1mm). The plastic is about 5″-6″ (126mm-152.4mm). The escape hatch sits above the opening, has a flange larger than the opening, and pulls upward to open. Rather than try to scrape the plastic to a more correct thickness, it was easier to open the hole and make a plug, pushing the plug to get the inch and a half (about 38.1mm) recess I was after (I think I used .030″ (.762mm) as the plug but I forgot to make a note):
I puttied over the plug on the inside so that the AM resin hatch would fit flush to the floor:
I copied some of the engine bay details from Mini-Art’s M3 Lee (Early). When I cast the floor, somehow I failed to notice that (what I think is the oil reservoir) has a substantial bubble:
I cut the hole to a relatively even hole, trimmed pouring block resin to a tapered fit, glopped a generous portion of superglue into the opened hole, and stuffed the tapered pouring block resin into the hole. I let it sit overnight so that the superglue was well cured (in the third photo it looks as if there’s a gap around the plug but there isn’t…that’s superglue). Once painted, shaded, and with a radial engine stuffed into the same area, I doubt anyone will ever see it, much less be able to critique my patching job:
I used Squadron Green putty to make my first pass and blend the added plastic to the diff cover:
It was okay, as far as it went…which wasn’t quite far enough, so I used 3M’s Acrylic Putty to finish blending. Later I will add bolts because the differential cover, whether three piece as this one represents, or a solid casting, all bolted to the upper and lower hull (I should also probably get my mitts onto some Mr. Surfacer as well so I can replicate the as-cast texture):
I used .020″ (.508mm) styrene for the lower engine access plate (which will also get bolts added):
Back into the crew compartment, I started working on the canisters of the fire-suppression system. This starts with cutting away the pouring block and putting back the detail lost. It also entails reattaching the valve/gauge assembly that got knocked off (using my traditional pin and glue method):
I get to do this again because there were two canisters (and you can see where the gauge has already been knocked off the valve…or it simply didn’t pour):
I used the punch/die set to knock out three discs to make the gauge and before I add the conjoined canisters into the interior I will add the Mystery Bit (seen on top of the other gauge):
With most of the details added to the belly of the tank, I used Vallejo’s Acrylic Putty to fill in the alignment marks and mistakes. Since I’ve brought up the subject of mistakes, gimlet-eyed readers have no doubt noticed that I have extended the resin sponson bottoms all the way to the back of the sponsons. Yep…correct for an M4A3…incorrect for an M4. (This also explains why the AM set has abbreviated sides…Tamiya actually provided the parts that would otherwise go there, so both the sponsons and the upper sides of the engine bay will get trimmed. Later):
Since it isn’t the 60s anymore (and I am not a kid) (substantially), I am not a fan of “working features.” Having said that, I again remind y’all that I am a creature of mood and whimsy. Not understanding why myself, I have decided that the engine covers must open and close. (Well, doesn’t THAT simplify things! Having had Covid last month, I blame Covid-brain.) I started with the rear engine doors. I held the doors in place and drilled through the hinge parts in one pass, thereby making inserting the wire I’m going to use as hinge pins even possible, much less easier:
That worked well, so I tried it on the top engine covers. That didn’t work worth a rodent’s rectum. That so didn’t work that I bitched up the kit’s front engine cover (very thin drill, too far to go to reach the areas that had to be drilled, which caused the bit to bend and the hole to be drilled as a curve, and that utterly screws up a hinge). Okay. Since it has become evident that I cannot drill out the hinges with them in situ, the end result is that to have the top engine cover open, I have to scratch-build it.
Lovely idea! Let’s DO that!
::insert eye roll here::
The upper engine covers are three parts, of which two bolt into place. The front engine cover (which is the one I bitched up) has the air inlet for the engine’s cooling fan (obviously, Shermans with the Continental radial aircraft engine are air-cooled), as well as a couple of armored fuel cap covers.
Step one is to cut three pieces of .015″ (.381mm) styrene to replace the kit’s covers. I used the thickness I chose for scale thickness. Once I had all three parts cut (which for simple rectangles took me far too long) and fitted, I noticed that allowance had been made by the kit engineers for the out of scale engine covers to sit flush with the surrounding surfaces. That meant that the scale thickness covers were recessed and should not be:
My first attempt used .015″ (.381mm) shims to raise the covers:
That didn’t exactly do it, as the center cover in the photo below shows:
Since both for forward and rear covers are typically bolted down, I shimmed the covers and not their seat, which is why in the above photo they sit even with the surrounding hull. I added .020″ (.508mm) strips to the shims already glued down and that brought the middle cover up to where I want it:
The rear and front cover will have bolt heads added later. For now I have to get the missing details added to the front cover. That started by sawing off the bullet-splash lip:
You can see that it wasn’t my cleanest excision. I cleaned up and leveled the U-shaped part (on the right in the above photo) and then glued it down to a flat section of .015″ (.380mm) styrene to replace the kerf. Once glued onto it, I could see an area where the plastic of the excised part didn’t meet with the plastic of the kerf replacement. I added a couple of pieces of .010″ (.254mm) and .005″ (.127mm) to fill in the gap:
I applied Tamiya Extra Thin cement liberally and once the plastic started to melt, I clamped it all into a vise to cause the squidge to flow and fill gaps and to make the gooey plastic a bit more level:
And what with all the cutting, fitting, fixing, and of course Colorful Invective (often applied while crawling around looking for the sodding small part that just tried to “tick” its way to oblivion), I never did do any work fitting that engine…
M4 (Tamiya) Build #2 – Assembling Bits for the Lower Hull Continues and I Find Out That Proper Fit Will be Challenging
Rather than thrash about the way I had been doing regarding the interior bits, I decided to structure events more logically and started with the front of the crew compartment. That starts with getting transmission parts ready to use:
Getting that part in the lower right of the above photo cut away from the pouring block and cleaned up was another exercise in trying to trim something with the consistency and structure of over-cooked spaghetti. (This is fun, right? This is why I do this stuff, right? Right?!)
Trimmed and cleaned up parts start getting added to the transmission body. Any modeler that’s reading this knows that another problem (not “issue,” because I’m not a publisher) we frequently, FREQUENTLY, have to deal with is a paucity of hands. We really need four instead of the stock-issued two. To get a couple of the tiny bits (lighter colored resin just about centered in the photo) showed me that I needed some way to keep them in place and apply superglue. Cue the Panavise! After (gently!) clamping the transmission body in the vise, I diddled and fiddled until I had the angle of the transmission such that gravity would hold the tiny bits in place long enough for a touch of superglue applied with the tip of a needle to set them properly in place:
The reason for the different colored parts was due to trying to add enough black dye to white resin to color it gray without adding too much and making them black (you’ll see those black parts later in this build). The dropper of the dye bottle doesn’t “drop” as much as it dribbles. I usually (in fact, almost always) mix resin in once ounce increments and the dye is VERY CONCENTRATED. Dribbles are not as precise as drops, resulting in varied coloration in the castings. The two levers at the rear of the transmission are the shifter (the long, lighter-colored part) and parking brake (the other one). The knob of the parking brake was not to my satisfaction so I used a tiny glass bead and replaced it:
[As an aside, I purchased this AM set in 2014 when I got back into modeling after 24 years. I was gobsmacked by the incredible detail provided. It wasn’t until about 20 minutes ago when I was editing the photos that I noticed the faint striations on the body of the transmission between the ribs. These parts were 3D printed! Given the state of 3D printers eight years ago, CMK did a great job producing these parts!]
On either side of the transmission are the seats for the driver and co-driver and I started with the co-driver’s seat. I used a 1″ (25.4mm) 90 degree angle to set the correct angle between the seat and seat back. Again, using gravity to keep parts aligned, I placed the angle and seat parts on an old resin cover to a welding mask and then elevated it just enough to align things while gluing:
The parallelogram base enabled the co-driver to ride with his head out (don’t go there) or drop him down into the hull so that closing the hatch didn’t result in a massive headache (and probably a concussion spiced with stitches). I assembled the base and then glued it to the seat bottom:
For whatever reason (craziness, perhaps?), I like altering the heights of these seats. The driver’s seat mount was utterly different from the co-driver’s seat mount. Instead of a parallelogram pedestal it was comprised of a telescoping column. That’s a lot easier to adjust than the height of a fragile and tiny parallelogram (#90 is the telescoping pedestal and the copper tubing and styrene rod made altering the height possible):
This is how far the seat was raised:
As you can (in a blurry sort of way), there really isn’t all that much difference between the height of the two. In comparing the as-provided height of the base and what I modified that height to be indicates that the co-driver’s seat was actually supposed to be (according the manufacturer) higher:
Well…so much for that.
I went back to the transmission and copied some small PE parts using .005″ (.127mm). Simple parts, easy copy, but then I looked at the directions to see where they go. What I found was something a bit less than specific (the parts involved are circled):
And while I was dealing with that little puzzle, I cut part PUR45, which is the platform the box mounts onto, from the pouring block. Did I mention warm hands and flexible-when-warm resin?:
Yeah. That was fixed:
So far the instructions have been fairly decent. I decided to check later steps to see if perhaps there was an actual indication regarding the location of these small bits…and there is:
They were glued on and events proceeded with a flattened mounting plate (and yes…I know the partition’s sections aren’t square…that was fixed later):
One of the tasks that was hanging heavily over my head was the reinforcements that were part of the seats’ backs. The AM set offered PE parts, but why do that at this point? Instead I figured out a way to do them in .005″ (.127mm) styrene. I had made the box itself from copper shim stock because that part has structural requirements (albeit slight). Rather than do the partitions in copper, I used styrene. But look at all these holes I have to drill:
Yeah…just try to get 28 holes that perfectly aligned. Pity that I couldn’t use the PE parts as guides…oh. Wait. I can! Drilling, however, tends to elongate holes in thin material as well as create all kinds of feathering on the reverse side of the hole being drilled. I minimized that by making a sandwich (or more accurately, a temporary laminate). The drilling backing was a scrap piece of .040″ (1.016mm) styrene onto which I stuck a piece of double-sided tape, then the .005″ (.127mm) styrene I wanted the parts to be, another piece of double-sided tape, and then a piece of .020″ (.508mm) styrene on top of it all. Then I used the PE parts as my drilling jig (I didn’t drill out the tiny holes because evidently even my nit-picking insanity has limits) (who knew?):
The downside to doing all that was the fact that I’d slightly misaligned the .005″ (.127mm) plastic and didn’t notice that a corner was missing:
As you can see in the above photo, even by laminating the plastic, I still ended up with feathers or blow-out on the reverse side. While grumping about having to redo one of them, I stuck the piece that wasn’t missing its corner to double-sided tape and used a fresh single-edge razor blade to cut the feathering away. And then I had the notion that I probably could add styrene to the missing corner while that part was on the tape. So I did and it worked:
Even though my shop has no carpet that would morph into the dreaded Carpet Monster, small parts are SMALL. Many hours are spent per build crawling around looking for what the “tick” of my tweezers have told me has departed. And when I go looking for the part, I go looking for the part…up to and including moving EVERYthing:
Sometimes I even find the missing part (and as of this post, I’m adding to the After Action Report how much time during the build I’ve spent crawling around looking for things).
With the transmission mostly built and the glue totally cured, it was time to add the transmission to the back of the differential housing. That started with attaching the cross-tube for the steering brakes. Because there are very small levers attached to it, I drilled out every place a pin had to go and added pins (lessens the amount of hand required to assemble things down to the mere two I was issued):
Then the painstaking job of getting the transmission correctly aligned began. In the photo above, please note that there are no locator marks other than the easy-to-overlook flat spot at the bottom of where the transmission mounts to the differential case:
The mounting bulkhead for this subassembly was cast separately (not my idea…) so that had to be added. Once again, the part wasn’t quite large enough. So I clamped and glued it to the best of my (limited) ability:
When Tamiya cut the dies for this model, they had mistakenly added “cast texture” to sections of the multipart glacis. And while looking for something entirely different (casting marks of the many different subcontractors who made various parts), I noticed that the Sherman hull that Tamiya copied is an ALCO (American Locomotive) hull. When you look at the mount on the glacis where the bow machine gun goes, you will (or should, anyway) notice that the bulge isn’t circular overall. There are straight sides and a rounded top. This shows that this hull is an ALCO hull. The same diagram that showed the ALCO hull also showed how the different plates were welded together. Most of the glacis is rolled (aka flat) plate with just the crew hoods (the bulges around the front of the hatches) and bow machine gun plate being cast…and of course Tamiya had everything on the glacis with that cast texture. Oh. And they got some of the plates incorrectly as well. I used Dymo label tape as my straight edge and scribed the correct panel lines and filled the incorrect seam between the hoods, marking the rolled armor with an “F” (because I’m easily confused, as you can tell by the fact that after laying down the lines I still had to scribe them instead of using the tape as my scribing guide):
I used Vallejo acrylic putty (#70.401) to fill in the weld lines…all of them all over the upper hull, then I started sanding away the cast texture and used 3M acrylic putty to fill in the really deep areas of texture:
Dry-fitting the transmission assembly and driver’s floor showed me that I had the steering levers, shifter, and parking brake handles slightly out of position. Here’s where having resin that is flexible when warm came in handy. I used a hairdrier (LOW SETTING!) to make things flexible and coaxed them into their corrected positions:
Back inside the hull, I wanted to replicate where the bolts that hold the suspension bogeys in place protrude into the interior. That started by making a pattern of the bolt pattern and location with Post-It Note paper using the locating hole for the kit’s bogeys for alignment:
Then they were aligned inside the hull and marks poked through the paper into the plastic:
None of the Grandt Line bolts I have are the correct size so I scraped sprue into an octagonal cross section and then stretched it:
Then the sprue was salami-sliced (why salami? Why not bologna, turkey, or roast beef?) and the “bolt” heads glued over the depressions poked through the paper (the bolts to the right in the photo are in the engine bay and will be covered by the fuel tanks so I’ll shave those off):
When these tanks were upgraded to increase crew protection, it had already been determined that the vertical faces of the crew hoods were susceptible to penetrating shots (like the rest of the Sherman’s armor wasn’t?!). Flat armor plates were welded in front of the hoods at an angle that was assumed would offer better penetration resistance (snicker). Tamiya also molded these add-on armor plates with cast texture so that had to go. Rather than sand them down, because being easily seen in position would probably make them noticeably thinner, I used double-sided tape to hold them while I used a skim coat of 3M’s putty to fill in the texture, sanded them flat, and then glued them in place on the glacis:
There are easily seen weld beads where the tops of the armor plates welded to the hood. Later I will use the Vallejo putty to replicate those.
Before I started hanging more bits from the lower hull, I added the tow hook mounts:
At this point I wanted to dry-fit the interior assemblies and check the engine for fit. Good thing I did because I found that it did not. I needed more room at the rear of the engine.
And while I’m touching on that subject, a word about mixing AM sets. CMK made the interior set and that includes the firewall. TWS made the interior set for the engine bay that also includes a firewall. Roughly speaking, that means I had (yes…past tense) double the thickness with the firewall. Tedium ensued as I filed, sanded, ground, curse, whined and whimpered each firewall to about half its original thickness. If each part is half its thickness, that means I have two parts that combined have a single thickness. Easy notion. HOURS of work followed…and remember, thin sections of resin don’t hold up dimensionally to warm hands. It was like trying to sand a latex glove at times. But of all the things I’m good at (both of them), giving up isn’t one of them. I got them thin, flat, and taped together before I tried dry-fitting (you can see the two parts taped together). And I still needed more room:
I know it looks like I have just enough room, but I don’t. The engine still has space-filling bits that hang off the back of it. I still need more room.
If you look at post #1, you will see a part sticking out of the front of the engine. This is the throwout bearing and driveshaft mount. Well, even on the actual tank, that bearing/shaft assembly is inside the firewall and will never be seen. I cut that piece flush with the engine and it worked…I have JUST enough room (I think…subsequent dry-fittings will tell):
So as of this moment, it looks like everything will fit. Next month should give me that answer. If it doesn’t fit then this build won’t have its engine.
M4 (Tamiya) Build #1 – Parts Layout and Thinking Crazy Thoughts…and Then Acting On Them
Having already done a later Sherman variant, I wanted to work on the variant that started the lineage, an M4. This is the kit I’m starting with (and I’ll get to why another old Tamiya kit shortly):
This is the typical Tamiya Sherman from the mid 90s. It lacks sponson bottoms, the grab handles are cast as fins, the welds are recessed instead of raised seams, and all the silliness Tamiya was known for back then. Instead of going the AM route for this build, I’m using this kit as the starting point because much of it won’t make it out of the box. As an indicator of that, compare the photo above with the box contents and then look at some of these (as well as a some of the parts I’d shown in the previous post that I’d copied):
As you saw in the previous post, I’m doing a full interior. What I don’t think I got into in the last post is that I’m also doing an engine for it and using MiniArt’s R975:
Since the M3 Lee I’d started has become a shelf-queen, I’m going to use the engine I’d built for that build in this one:
The detail of CMK’s AM set is impressive and I think it would be a shame to hide all those nicely done parts inside where most of the details can’t be seen. I had briefly considered doing a cutaway model but I live with this critter:
She is a cat hair factory and is very giving. I do NOT want to try to get cat hair out of a cutaway model. Instead, I’m going to replace a side panel of the upper hull with clear styrene and to make creating a clear panel for the curved turret SO much easier, I’ll be using this instead of the Tamiya turret that I special-ordered from TMD (who is, I’m sad to say, closing their doors at the end of 2022…so if you want something they offer, get them now because the clock is running out):
I will be using Panda Plastic’s tracks again because they’re just easy to work with and fit well. I’ll also be using a bunch of other items from TMD, Resicast (okay…not “a bunch” because though they produce an excellent product, their prices are steep), some old Verlinden bits I have laying about, and plenty of spare parts. It’s a Sherman. There will be “stuff” hanging on it.
This is going to be a Chinese-interesting build. The kit, an engine from a different kit, AM parts from four (possibly more…) vendors, and none of it is really supposed to play with each other. After having spent many weeks this summer making molds and casting resin, it’s finally time to start putting some of that resin together.
Let’s do that now, then.
Since I’d copied the resin parts, I wanted to see if I could substitute styrene and copper shim stock (.005″ (.127mm) for the PE parts that came with the set. To see if that would work (at all), I started with a couple the boxes that populate the floor of a dry-stowage Sherman. The box to the left in the following photograph is a floor-mounted ammunition bin for the 75mm gun. The body is resin (and can be posed open to show the ammo stowed inside) and the top as well as the front doors have PE parts supplied. Instead, I used .005″ (.127mm) for the doors and hinges, with stretched sprue for the locking loop. The box to the right in the photograph is the battery box, again with a PE part that I replaced with the same thickness of styrene. Instead of using the resin conduit that comes off the battery box that the switch box hangs from, I used .040″ (1.016mm) solder:
From what I’ve read, a lot of M4s that took part in the D-Day invasion were older tanks that had been rebuilt and upgraded and I wanted to replicate one of those. These are PE/resin parts in the AM set:
The AM set provided the PE faces for the later (left side) and earlier (right side) instrument panels. The set also provided the resin body for the instrument panel but no resin body for the earlier panel (though film gauge panels for both were supplied). Since I’m using the earlier panel, 0.060″ (1.524mm) styrene, though slightly thinner, works well for the instrument panel body.
A very handy method I’ve discovered to make straight cuts in small pieces of styrene is to use a straight-edge razor blade and a hammer (anyone who thinks force has never solved anything has obviously not built anything):
Works well, eh?:
I certainly thought so. I used the PE panel to trace its outline onto a piece of .005″ (.127mm) styrene and used my punch/die set to make the holes for the film instrument faces to show through:
I was so pleased with how this was going that I just started adding all the little surface details (without checking anything else…can you see It coming?):
Yeah…I didn’t think so. Seeing it coming, I mean. I placed the film of the gauge faces over the body of the instrument panel and laid the face over it…and couldn’t see a damned thing. Just black dots. I went into the decal/transfer drawer and pulled out Archer’s (no longer available) US instrument faces out and realized that the holes I’d punched into the face of the panel were just way too large.
So I did the whole sodding thing again, only this time I measured things first AND did something really wild. I consulted Cunningham’s book on the Sherman. That bit of tomfoolery enabled me to get the correct gauges in the correct places and all of the correct size and that also included the correct switches (the tan part between the panel and the penny is a section of stretched sprue that I did an Icarus with by bringing it slowly towards a candle to mushroom one end…it looks like there’s a manual fuel priming pump on the panel face):
It is VERY difficult for me to get all the gauges exactly where they need to be so if they’re close enough, I check to see where white is showing that shouldn’t be and lay in a bit of flat black to hide my imperfection(s):
It all ends up working. Eventually:
I turned my attention to the driver’s position. The floor is raised above the bottom of the hull and the part the AM set supplied was diamond-tread PE. Rather than use the PE, I copied a section of plastic diamond tread floor that is supplied with Academy’s M3 Stuart kit. I used the aluminum foil that scalpel blades are packed in, folded it over the edge of the Academy kit’s floor, and embossed the tread pattern into it. The PE part:
The Academy M3 Stuart floor:
And the aluminum foil after being embossed with the tread pattern:
Then the PE part was traced over the foil and trimmed to shape:
Even though the aluminum is heavier than the standard foil used in kitchens, there isn’t anything very structural about it which required I add 0.010″ (.254mm) styrene as a backing plate:
Which were given the final trim using the razor/hammer trick:
The braking/steering levers were resin. I have warm hands. Why do I mention that? Because if you want to change the shape of a resin casting, like maybe it was misshapen or warped, warmth returns enough plasticity to the parts to allow them to be reshaped. Yeah. The levers were so small that just the delicate task of removing them from the pouring block warmed them enough so that I felt as if I was trying to carve a strand of cooked spaghetti. I replaced them by using 0.020″ (.508mm) styrene with 0.035″ (.890mm) grips. Since the pivot shaft had been cast in halves and attached to the levers, that also had to be fabricated:
As you can surmise from seeing the driver’s floor sitting on top of a penny, these are small parts. Fairly small parts. This is the foot-throttle:
Warm hands also turned that rubbery. It was adjusted to shape. Often. Even frequently sometimes.
The grips were added and the proper angles of the levers adjusted:
All the other parts were removed from their pouring blocks, rubberiness dealt with, and after painting the sub-floor flat black, it was assembled:
There is a partitioned box that sits on top of the transmission that’s intended to stow spare periscopes in. I replaced the PE part with .005″ (.127mm) copper shim stock and even managed to solder all four edges where they meet!:
I used a fine file to true the edges around the opening so that they are all even and then added .005″ (.127mm) styrene to the inside to complete the partition (it took me longer to add just the styrene than it took to outline, cut, file, solder, and file again the copper box):
Assembling the bits for the lower hull continues next month.
M4 (Tamiya) Build #0 – Behind the Scenes of Behind the Scenes…What I Want to do Before I can do That
This post will be different from how I usually start things off. I don’t have to do a “Brief Overview” for it because I did that for the M4A3 and why do it again? “Same” tank, same info. What is different this post is what I wanted to do before I get to do what I want to do.
When I did the M4A3, that was my first build after a 23-year hiatus. That build was to see what had changed in the hobby (EVERYTHING), what had changed between 1991 and 2014 with my eyes and hands (EVERYTHING), and what would it take to remove the mental brakes and just go for it (everything ELSE). One of the first mistakes I made (of a few…) was with the AM set I purchased for the interior. I wanted to do a later production A3 and that critter had a wet-stowage interior. Instead I purchased a dry-stowage interior set from CMK. Well, duh. Fine. Stored it away, got the correct AM set from TWS, and off to the races (in a doddering and tottering sort of way) I went. What I remembered was how detailed and amazingly produced the CMK dry-stowage set was. It was so well done that I wanted to show the interior off when I got around to doing a dry-stowage M4. I’ve seen tanks with cut-out sections and though I like them, I don’t want to live with one because DUST AND CAT HAIR ARE NOT IN SHORT SUPPLY HERE. The notion, though not gone, sort of languished in the (massive) bin of all the other Great Ideas I’ve had and not gotten around to doing yet.
My back is shot. Utterly. That means laying in bed awake and waiting to (see if I can) get to sleep. My mind will wander during those (frequent) times. I took a break from the bench in June and just about the time July arrived, so did a notion from the Boys in the Back. Y’know, if you want to use that CMK set you’ve had on the shelf for over a decade, now, why not build an M4 with transparencies replacing the opaque instead of cutting holes in the hull and turret?
What a great notion! (FYI, a “great notion” isn’t necessarily an “easy” notion. Just thought I’d throw that in here.) That’s what I’ll be doing with my next build. Cutting holes and plugging them with clear plastic/resin. NEVER have to worry about DUST AND CAT HAIR getting in that way (open hatches not withstanding).
The CMK set is so nice that I wanted to be certain I could get another set because this M4 won’t be the only Sherman I’ll be doing (assuming I live that long). And it’s a good thing I looked because well, bugger-all, I can’t find any available! Pity I don’t know how to make molds and pour resin because…uhm…wait a sec. I do know how to make molds and pour resin! I’m actually all tooled up to make molds and pour resin.
That’s what this post will be about, how Modeling Magic happens and how utterly magical it is when something goes gloriously off the rails… So. That said…
This is the CMK turret AM set I’ll be copying (#3027). I will also be copying their inner hull detail set (#3026)*:
I get my molding/casting supplies from Smooth-On. I use their Mold Max 14NV silicone rubber compound. It’s a fast curing tin-cured (he says like he knows what the aerial intercourse “tin-cured” means) low-viscosity compound that will flow into any crack and crevice and, unless one takes the proper precautions, between those cracks and crevices also (more on that later). Pot life is 40 minutes and cure time is 4 hours. I use Smooth-On’s polyurethane resin, Smooth-Cast 322 Off-White Liquid Plastic (which it really isn’t). Pot life is 10-20 minutes with a cure time of 2-4 hours depending on the mass the the part. (more on that later, too). The rubber compound is mixed with a hardener using a mix ratio of 10% hardener by weight. The resin is a simple A and B arrangement and it’s mixed 50/50 by volume. When the resin cures, it ends up with an off-white color that I’ve found my failing eyes don’t like; it’s hard to see details. To remedy that, I add Castin’ Craft Color Pigment in black. The goal is a medium to light gray (or grey, if you drive on the wrong side of the road as a national thing and are right fond of tea) but due to the consistency of the dye and that it is very concentrated, getting it the same color each time I pour resin thus far eludes my meager skill-set. (I persevere, which means I don’t give a snort what color it ends up so long as it’s not white.)
The molding compound isn’t the most expensive thing I’ve tossed shekels at but, being a parsimonious git, I hate wasting money. I want to get as many molds as I can out of the stuff. Because I really cannot use 5 gallons of the stuff before it goes off (yep…it’s got a shelf life), I buy the molding rubber compound in two pound (0.91KGs) lots. I also use modified Lego blocks and base to construct my mold boxes, so I have a mock-up that lets me, well, mock up how the mold will be laid out. To maximize molds with the minimum amount of rubber, I molded turret parts and crew compartment parts at the same time (and a few years from now when it comes time to make more of these parts I’m going to have SO much fun figuring out where what is…clever of me, eh?):
With a game plan in place, it was time to build the mold boxes. I’d made brief mention of the fact that I use modified Lego blocks. I have to for one major reason: The molding rubber has to be degassed (you do know that there’s a glossary on the site for those WTF words, right?). Air, being a gas under what we egocentrically assume to be “normal” circumstances, gets into everything. Degassing entails exposing the item we want to remove air from to vacuum (really low air pressure, not that thing that you scare the cat with). Lego blocks are neither air tight nor water (or in this case, rubber) tight. To keep from drawing air through the mold (which is why I’m degassing this stuff…to get rid of the air) where I don’t want it, I have drilled holes in what I want to be the outside of the box (and if you go this route, look inside each block because they aren’t all built identically…sometimes multiple holes have to be drilled so that no air is drawn up through the mold):
If I don’t attach the parts I’m copying to the base-plate they will float (which you will see evidence of shortly). I use white glue (PVA, if I’m showing off) to temporarily attach parts to the base-plate. And because the rubber will seep through any gap, no matter how small, and continue to seep through said gaps until it hardens (4 hours, y’know), it’s possible to have all the rubber seep out of the mold. Two pounds (0.91KGs) of the rubber costs me about $75 dollars (forget currency conversions, you’re fortunate enough that I convert Imperial size to Metric, so don’t get pushy) and wasting any of it doth vex me most puissantly. Look at the photo above. You will see gaps between the blocks. I line the inside of all my Lego mold boxes with “scotch tape” to block the rubber from seeping out. However, I also make a gasket of PVA (or white glue if I don’t care what you think) around the outer edges of all the blocks that come in contact with the base plate to form a seal. I have learned to let this seemingly pour-ready mold box sit overnight so that the glue (whatever I call it for whatever reason) will set up as well as it can. Here is a Lego mold box all sealed and ready:
I use this scale to get pretty accurate weight measurements:
I don’t have any photos of the actual process of pouring rubber, adding hardener, because I don’t have all the hands I would need to be able to mix and operate a camera (or phone…welcome to the 21st Century). The rubber is poured in first. According to the settings on the above photo, I’m going to use 200g of rubber. That means I have to add 10% of hardener due to the 10/1 mix ratio. The rubber goes in, then the scale is adjusted so, using the above photo as the example, I then add 20g of hardener. As soon as I start adding the hardener I start the timer and then start mixing. I use a paint scraper and mix thoroughly, and that adds a lot of bubbles to the mixture. Bubbles are Bad Things and they seem to always congregate where important details are (because aren’t all details “important”?). To rid the mixture of them the mixing container is put into a vacuum chamber for 5 minutes to remove the really big bubbles:
Four minutes at 29″ of vacuum gets this result:
Which results in this once the vacuum is released:
Mixing takes about 2-3 minutes and the first degassing lasts four minutes. With a 20 minute pot life, I still have about 13 minutes to pour the rubber into the mold and degass it:
I prefer to remove the mold box from the vacuum chamber 5 minutes before the pot life limit. This allows the rubber to settle in around the parts I’m making a mold of.
I had mentioned earlier that if a resin part being copied comes loose from the platform it will float to the top of the rubber. Guess what happened:
Should that happen, just use tweezers to pull the dislodged part out of the rubber and set it on something to allow the rubber to cure. Once it has you can cut the rubber away and try again:
Four hours later the mold box is pried away from the base and then from the top down I start removing the blocks until I have this:
I clean up the mold by using scissors to trim each of the 12 edges. Once that’s done, I start cutting the parts in the rubber block out. Most times I can just cut around the base to extricate the part:
And there it is.
Being observant, of course you look at that and wonder, “How the hell will I remember what this mold will create?” Glad you asked. Mark it with a ballpoint pen (you will discover as I did that silicone rubber doesn’t like being written on, the ink never dries, and the merest rub across the surface eradicates whatever was written on it. Before the mold is filled with resin, use your phone to take a picture of it so that you can redo the labels later after all the labels you started with are gone.):
The molds show so far are what I call (because I don’t really know what They call them) “encapsulating molds.” The part molded and copied end up completely encapsulated by the rubber. Sometimes one will have to cut a mold open to retrieve the encapsulated part. Don’t cut the mold completely! If you do, it becomes a stone bitch to align the two parts and the slippery resin to get something useful. Won’t work. I cut only as much of the mold as necessary to extract the part, leaving an uncut “hinge”. Most times that’s just down one side of the area where the part is. Sometimes it requires both sides to be cut. The cut sections will snuggle up to each other quite tightly if the mold is stored correctly. Silicone rubber has a memory. If the mold is stored under stress, as in, not utterly flat, and left that way, you will find that that is how the mold stays…and that means the part you’re trying to copy is deformed as well. Since the vacuum deforms the Lego platform slightly during degassing, I store my molds with the smooth top down. That works.
Another type of mold is an open-back mold, which, oddly enough, is exactly what the name implies.
These parts do not require an encapsulating mold because I only need the details from one side:
You will see that some of these parts have been attached to a white plastic back (the parts that haven’t been attached to a back will be prior to molding). This makes removing the pouring block so much easier. (Later you will see the mistake I made with the resin pour.) The gray parts at the bottom of the photo have oddly shaped plastic attached to them. The reason for that is because though I don’t exactly know how long they have to be to fit, I do know that they are too short as is. Before molding they were trimmed.)
Making the mold box and attaching the parts to the platform are all done in the same manner that an encapsulated mold was done:
Rubber compound was mixed, degassed, and poured likewise:
A note about degassing.
If you will need to degass something to make a mold of it, make sure that thing is solid. It matters less what the thing being molded is made of (as long as it’s not super-porous like a marshmallow is), but it certainly matters if there are air pockets inside it. Guess what happens if there are air pockets inside it and it’s then exposed to vacuum.
An explosion (okay, technically it’s an IMplosion but if you can afford the camera that can show the difference, can I borrow a lot of money from you?). Possibly a violent explosion. (Hmm…is there ever a delicate explosion?) (Okay, okay…orgasms…but that topic is for a different website.)
Be certain your master (the thing you’re molding…again, a different website for a different definition of “master”) is solid. No voids.
With all molds made, it was time to mix the resin and fill them.
Resin is a different beast than rubber. Rubber molds require degassing (regardless of what the manufacturer will sometimes state to the contrary). If the rubber compound generates heat (if I’m being fancy I’ll call that property “exothermic”), it’s so little that I have never noticed. Resin is a different beast! It is obviously exothermic. I had an “interesting” experience the first time I mixed resin. The result looked more like a medium to support bubbles and nothing like something that wasn’t supposed to have any bubbles. So I blithely degassed it.
Being exposed to lower air pressure really allowed the exothermic compound to create a bazillion bubbles and then the short pot life froze that frothy mixture solid. Fascinating texture and if I ever need/want to create that texture I surely know the process now! But since I do not, I went to the Interwebs and googled “resin casting.” That’s how I learned how different a beast resin really is.
Once the resin compound is mixed, to get a bubble free casting the compound is put under pressure. 15 pounds is normal atmospheric pressure, the weight of the air above us, at sea level. Where I sit is not that much higher. But normal atmospheric pressure is not enough to squash all those bubbles. That meant that I had to acquire a pressure pot so that I could raise the air pressure. More wandering around the Interwebs showed me an excellent way to acquire a pressure pot and still have money left over for beer (rum, scotch, bourbon, mead).
There are pressure pots intended for portable paint spraying. Paint fills the pot, the lid is clamped down, and the pot is pressurized, the hose and the spray gun are attached (think big spray can). But if one removes the siphon tube and plugs the lid, now that pressure pot can be used to pressure cast resin. I used the supplied pressure gauge, plugged the siphon hole with a brass plug, fitted a T-fitting so that I could attach the hose, and a valve to release the pressure slowly, to the over-pressure safety valve (set to blow off at 55 lbs.):
The bottom of the pressure pot inside is concave and I need it to be flat. I took a piece of laminated cardboard and made a base that would give me the level surface I needed (because resin starts as a liquid and tilting a liquid-filled container doesn’t allow the liquid to stay in the container):
I needed an easy way to put molds into the pot. I settled on using paper plates and cutting them to fit:
I also realized that I could stack levels if I used something to keep each level separate and for that I used the cardboard tubes from toilet paper rolls:
And then I realized that if I cut the cardboard tubes in half, I could fit three levels of molds into the pressure pot.
I started the compressor in the garage (adjusted to a maximum pressure of 55 lbs.), trimmed paper plates and toilet paper tubes, and laid out everything I needed to mix resin. I put 40ml of part A into a disposable mixing cup, added what I’d hoped was eight drops of black dye, started my timer, and added another 40ml of part B and started stirring quickly. Again, a shortage of hands and a short pot life precluded photos being taken, but here’s the pressure pot filled with molds/resin, pressurized, and attached to the compressor (because all seals are imperfect, I leave the pot connected to the compressor and as pressures drop, the compressor kicks in and brings the pressure back up):
A thing about exothermic reactions…or at least the exothermic reaction of the resin I use. The more massive the shape, the faster it will cure. Within minutes of the pot life expiration, the remainder of the resin in the mixing cup is rock hard (and note all the bubbles on top):
This is the results four hours later:
When the parts are demolded, the really thin parts haven’t really cured fully and they’re a bit flexible. I find this property to be very useful. Quite frequently the parts have undercuts that the mold will grab. Being slightly flexible, especially for larger thin sections, allows the parts to move a bit to escape the mold. Once they’re out of the mold, gently moving and bending them will return them to the desired shape. The really thin parts will often deflect again. A couple of days later, nothing is really flexible anymore. Heating the cured resin will temporarily return enough flexibility so that they can be coaxed back into the proper (or desired) position.
Mixing resin, filling molds, repetition and this is where things go:
You’ll note 3-4 different colored parts in that photo. The white parts are how the resin sets up without adding dye. The black parts are what happen when too much dye is added. The varied gray parts indicate just how fussy “dripping” dye into the resin actually is. The dye is a gooey substance and the drops are inconsistent in volume, making it really difficult to repeat any amount with subsequent castings.
One can never know so much about anything that there is not room to learn more. I offer this exhibit:
Most of the resin that was poured into that mold went to fill the plastic backing. I took the parts that were so afflicted (essentially all the parts cast in open-back molds) along with my safety glasses, hearing protectors, and dust mask (an OSHA grade mask) outside and ground away most of what I should not have poured in the first place. (Would that I could learn using any method other than trial/error.)
And (aside from the mistakes presented) doesn’t all that look easy? Well…for the most part. And then there are the various excursions sideways.
Sometimes I err (I know, I know…just work with me here). In this sequence I will show you what can happen should a caffeine-based life-form attempt to adjust the scale to add the correct amount of hardener to the rubber prior to caffeine consumption.
The ratio of rubber to hardener is 10/1 respectively. Easy, yeah? I needed 200g of rubber, so that would be 20g of hardener. No problem. Started the timer, filled, added, and mixed, then I degassed the rubber, filled the mold, degassed the mold, and went off to the rest of my evening. Got up in the morning, fed the cat, consumed my caffeine, and went into the shop. A faint “uh oh” whispered in the back of the mud-infused thing my brain is at that time of day because the mold box came up easily which is unusual since when the rubber hardens it grabs both the box and the base. Usually. This time this is what happened (because there was no solid rubber anywhere in this pour to grab anything):
There was a little hardener in the mix, but nowhere near enough. How I screwed up basic math I have no idea…but clearly I did. The mold box was broken down and the Legos cleaned. Then the parts were pried from the base and cleaned:
And what a gooey, miserable, let’s-stick-to-EVERYthing, mess that was. I had to salvage these parts because the reason they’re being copied in the first place is because I can’t get more of them (the part in the above photo is a TWS part, who’s closed their business). Between soapy water and lighter fluid and hours of very annoying attention, everything was finally cleaned (wonderful way to spend a day, right up there with root canal and the day prior to a colonoscopy):
Having gotten the cleaning accomplished, parts glued to the base, another mold box was assembled, and I went through the mix and stir process (CAREFULLY) of getting the mold rubber ready to pour, and then did so. I did say “carefully,” but evidently I didn’t act “carefully.” I degassed the rubber, poured the mold, put it in the vacuum chamber, and then my bladder delicately informed me that I had 30 seconds before a soggy mess ensued. When I came back about two minutes later I found this in the vacuum chamber, all nice and solid: