Paint crinkling

From time to time I run across this problem in painting and can't figure out what is causing this sporadic crinkling of the paint. Seems to be in the surface or primer or some contamination but have been cleaning it all the same. Looks like this:

One thought..How clean is the air/water filter on the air line? Looks like a circular pattern in one area like it's could be what came out of paint guy nozzle.

If I resand and shoot more paint the crinkling reappears so I think it must be something under there but sanding, degreasing, or cleaning so far hasn't helped but this sure is getting frustrating. Thing is, over 95% has turned out great.

If I resand and shoot more paint the crinkling reappears so I think it must be something under there but sanding, degreasing, or cleaning so far hasn't helped but this sure is getting frustrating. Thing is, over 95% has turned out great.

Maybe silicone contamination on the part, at any time have you used any silicone spray lubricant near it or residue on hands,or shop rags?

Surface Contamination

IMHO you are dealing with surface contamination, either oils (even your hands can be responsible) or silicone as previously mentioned. I spent 30 years in the auto painting business and it is simply the first coat (primer I'm assuming) did not completely "wet" the substrate. Fish eye eliminator can help if you are mixing your own coatings but stripping to bare aluminum with acetone and cleaning the surface thoroughly with wax and grease remover or good old soap and water with a gray scothbrite pad, drying and then spraying. In future better cleaning before spraying will eliminate your problem.

This is very frustrating and I have had this a couple of times, though usually repairing old parts. The essence is the top coat volatiles, i.e. thinner, carrier solvents etc are leaching down into the substrate and reacting with it. It can be non compatible chemistry or simply cellulose getting under a drying topcoat and softening the primer which then contracts at a different rate, causing the crinkling.
As others have said, it can also be unclean substrate causing a poor adhesion of primer, which is why surface prep prior to priming is so essential. The quickest solution is to DA back to bare aluminium and re prime and re finish.

If you end up repairing old parts, thoroughly clean and de grease with a good non salt bearing detergent like Dawn, then when dry you can apply a coat of Bar Coat or similar which is an alcohol based lacquer. It doesn't react to the cellulose substrate and allows different chemistry to be applied above. It is particularly good on composite parts.

The other time it can appear is if you have used fade out thinner to combat runs or blebs. The Xylene in it is very penetrative !

Very annoying but not the end of the world.

Mike , what do you mean by DA back to bare Al? Not sure of the DA.

Thanks

Crinkle

Could be contamination but I think most likely the time between coats.
Directions on certain paints are very specific on time allowance between
Coats. Had a similar problem painting a panel.

Hornet2008 said:

Mike , what do you mean by DA back to bare Al? Not sure of the DA.

Thanks

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Not mike but look up da sander.

Mike nailed it. Incompatible topcoat and underlying primer or paint. Are you spraying a specific system taken from the manufacturer's data sheet, or random primer and topcoat choices?

FORANE said:

Not mike but look up da sander.

Click to expand...

Dual Action I think.

It's all PPG compatible product but 95% of it turns out clean only a couple random places where the crinkling occurs. It's as if maybe primer or paint was put on too thick? For example, i am painting stripes on top of a sanded or scuffed clear. As the stripe crosses the door area it is on the fiberglass door where crinkling occurs. In other areas it is over the aluminum.