I was spraying clear tonight with my new toy. It's a decent quality MiniJet style spray gun. I was shooting Certified clear and having problems (as if this plane hasn't been one, long problem). I was getting some pretty serious orange peel and thought after several attempts at adjusting the gun and compressor (making it slightly better, but not really solving the problem), OK, the material is just too thick. Straight out of the can, the stuff is like maple syrup. I had cut it about 75% (1 part paint, 3 parts thinner) and did some drip tests. I had thought it was fine.

So, I cut it another 25% (another part thinner) and tried again. Better, but still not right. Ultimately, I just filled the gun up with thinner and shot a medium coat of it over the already well coated, but orange peeled plane. Surprise, it laid right out. Nice, smooth surface.

So, the moral of the story is, if it isn't right, keep experimenting. Clearly, the clear dope was still too thick to lay out nicely. I'll cut it another 50% or so before the next coat.

Fun stuff in January.

Randy,
might be the mighty minijet atomizes to well! Thats what my thoughts would be. Glad you kept after it. Hopefully it dries as flat as it sounds like it flowed out. I guess the curse was a blessing since it was cold enough to allow the solvent to reflow the clear for you.

See, this is exactly why I'm afraid to spray my planes. If I had the same problem as Randy had, I wouldn't even have known what to try next. I'm just not prepared for big problems. It's pretty cold out these days and I don't really have a "indoor" place to paint unless I want to drive across town and use my business shop, and it's not heated. So i'm having to spray the Mustang outside in the dampness and then run it inside to dry. I don't like that.

Couple of things. The "coat" of thinner at the end is basically doing what Chris notes. Softening the surface so the solvents could escape. It also allowed the surface to lay out from the orange peel. Probably couldn't have gotten away with this if the temp had been warmer or if the humidity had been lower. It was just a means to solve a problem.

Interestingly, the gun is supposed to shoot at 10lbs (trigger depressed). Normally this means dialing the pressure in at the gun to about 22lbs. But I ended up having to dial the pressure at the gun up to about 35lbs to get good atomization. This sort of adjustment is just what you have to do to adjust to conditions.

Clint,

Don't worry. Just look at what the paint is doing. In this case. I initially shot paint at what normally works fine, but I could see orange peel that was clearly due to inadequate atomization. Sort of looks like you are shooting raindrops. Tried dialing up the pressure and it got better to a point, but still wasn't right. So, thin the mixture out until it is right. Unfortunately, I should have done all this on a test piece, but I didn't. So I kept shooting on the plane (and thinking I was looking forward to a lot of sanding) and making adjustments. When I had shot the whole plane, I realized that, very abnormally, it was all still quite wet. So I thought, OK, how do I get this still wet paint to smooth out. So that's when I decided to shoot the mostly thinner coat on. I figured what the heck. I may save myself some pain in sanding later. And as it turns out, it worked fine. The peel layed right out.

I think that's the point with a lot of painting. I'm still learning the tricks and quirks with this new gun and compressor, but some things are universal. As Chris notes, orange peel usually means inadequate atomization. This comes (given a good gun and compressor) from either not enough pressure or too thick of material (or both). Forget what the instructions for the gun say. They are usually a good guideline, but you have to do what works. Recognizing problems and knowing what to do to correct them just takes time with the equipment and knowing what it's supposed to look like. Not unlike flying a pattern.