Back before Facebook disgusted me enough to leave it, I had been a member of a couple of modeler’s forums. There were the standard questions (“What is the best kit for the Super Belchfire GT in 1/32 scale?”), and then there was the question about airbrushes. It was a good question. Are they necessary? What’s the difference between a single-action and a double-action airbrush? Is one type of airbrush better than the other? Inadvertently, I started a flame war when I said I thought that for my purposes (emphasis added here), single-action was good enough.

So, IS an airbrush necessary for a good paint job? No, not really. To my way of thinking, having an airbrush makes a good paint job easier to achieve.

What’s the difference between a single-action and a double-action airbrush? In the former, pressing the button on top allows the air from the compressor to siphon the paint out of the cup/jar, into the body of the airbrush to mix, and then pushes it out of the airbrush, across the few inches from the surface, and down where the modeler wants it. To adjust the width of the spray pattern, there’s a knob at the back of it that will move the metering needle in and out of the aperture and thus control the width of that spray pattern. It’s a much simpler machine and, again to my way of thinking, is why I like the single-action better. I don’t need to vary the spray pattern very often…and when I do, adjusting the knob at the rear of the airbrush isn’t a hassle. But I DO need to clean the airbrush very often…so a simpler machine makes sense to me.

The double-action airbrush is a bit more complicated. The button on top still releases the compressed air to flow through the airbrush. However, it does something else, too. Pulling back on the button while pressing it down will make the spray pattern wider. One can adjust the width of the pattern on the fly. That’s a great feature to have if it’s needed…I just don’t happen to need it. So a more complicated and harder to clean machine doesn’t make sense to me.

Either tool takes time and practice to get good with. The double-action airbrush tends to take longer to figure out than the single-action airbrush. The double-action airbrush tends to be more expensive than the single-action airbrush, too.

And once the model is done, all painted, decaled, weathered, and on display, can a person tell just by looking at it which type of airbrush painted it? I certainly cannot!

Yes…I’ve simplified things here. I didn’t talk about internal mix and external mix airbrushes, or pretty much anything else about them other than which type of action they are.