When spraying epoxy I get small 'dimples' of primer on my panel

L

larryq

For some reason whenever I spray epoxy primer (not just SPI, I also use Summit Racing's epoxy) more often than not I'll get tiny pebbles of primer in my paint job, so I have to sand with 400 grit before proceeding to the next stage. It's annoying. It's not everywhere in the spray job like measles; maybe two or three pebbles in a 3"x3" square.

The gun isn't dirty, I spray high build primer, basecoat and clearcoat with it and have no problem with those materials. And I always strain my material before spraying and immediately clean after every use.

What could be causing this? I have an Eastwood Concours hvlp gun and use a 1.4 tip with epoxy, with PSI at the gun inlet between 20-25 PSI. I generally hold the gun 6-8 inches from the panel.

Sometimes I'll thin 10% with reducer, other times not. Reducing makes no difference in problem, from what I've seen. What could be causing this?
 
If you're talking about the swiss cheese type craters, that is the first coat going on too heavy. But if it is the little tiny "sand sized" specks, I have the same problem. I have completely changed my air setup, everything except the gun. A Finishline w/1.5 tip. I suspect it is dry over-spray landing in the wet paint. I have since bought a Devilbiss Tekna, but have not tried it with epoxy. I'm saving that gun for base/clear. Since it gets sanded out, I don't worry about it. Though, I will also try Shine's suggestion to see if that helps.
 
turn in your fluid a half turn at a time. product is going on too heavy. also i find that the wax and grease remover is not fully evaporated even though it looks like it is. i follow Barrys instructions to the "T" i even wait an extra 15 between coats of clear
 
I have found that switching to 125 micron strainers for primers, clear, and solid colors has reduced the number of visible stray particles in my sprayed material, which is especially helpful for sealer applications.

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epoxy or primers create far more over spray than base or clear . cut your air pressure down a little at a time. too much air not enough fluid .
 
Crashtech, I'm using 190 strainer. I'll have to try 125. Shine, I will try lower pressure today, more fluid. The black "dust" overspray gets on everything in the booth, that's why I think dry/overspray is my problem. This is hard to get a picture. 1st pic, the little specks I don't know. Larry, the last pic is heavy spray, aka moon craters.
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that is heavy enough. those small specs are just part of the game .
the place by the window edge is likely a hand print causing the sag .

extending the induction time can help also. i let it induce overnight .
 
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Thanks everyone. To clarify, my particular problem is the sand-sized specks, not craters. I doubt I'm laying it on too heavy, more likely too much air.
 
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