Setting up the spray pattern on your paint gun

So everything is ready to go. I've gone over the car with compressed air to remove any dust. I've gone over the car twice with wax and grease remover. The booth is up and running, and all my lights are bright. The booth is just the right temperature. It's almost time to spray some paint.


But first, you have to adjust your gun. I had read and seen in the videos I'd gotten that guys would adjust their gun, but none of them said how to in any detail. I did find a pretty good write-up in Burton's DIY site that referenced this article on setting up your gun. The article was great, except that the terrible illustration at the end showed the ideal spray pattern, but was so vague. I couldn't really translate that to the real world.

I took my best guess and started painting my primer sealer and immediately got some really bad orange-peel in the paint. I finihsed off the panel I'd started (luckily the roof, which is harder to see than the other panels) and then played with my pattern a bunch. Here is a picture of varied patterns with slight tweaks to air pressure and fan size.

In this close-up picture below, you can see the first pattern is good, but there are some thicker paint drops mixed in with the finely atomized drops. This is no good. Those big fat drops are what pool and build texture, which is bad.

I would hold the gun 6" from the test paper (or spray booth wall) and pull the trigger fully, but as quickly as you can, letting off the trigger as soon as it is open 100%. I adjusted the fan first to get it to about 6" of spread, that's 6" band of thick paint, and a few inches of atomized dots on the top and bottom edges. Then, you add air pressure, or drop paint delivery spraying a test spot every quarter turn until you are almost out to just air with no paint. Those are the 3rd and 4th patterns in this picture. Same air + less paint = smaller pattern without any adjustment to the fan size, by the way. Then barely drop air or add paint by a 16th of a knob turn and watch the pattern until it is big enough and is giving almost solid coverage in the middle of you pattern, and you aren't getting big globs in the outer edges of your pattern. The outer edges of your patterns should be the smallest dots you can get your gun to spray but still get good coverage in the middle of your pattern. You definitely don't want any runs in your pattern anywhere. Once your coverage is thick enough to get paint on your project, but doesn't have big globs or specks, you will get nicely atomized paint. Between pattern #5-6 was a good pattern for me. Nice and even. I hope this helps some.