Helping my neighbor paint a 32 Ford kit car with fiberglass body. While painting basecoat/clearcoat we are running into a problem with paint wrinkling on three spots. Rest of the car is great except for 4" spot on roof, and 6" long spot on radiator cover. Also have a small one on side of hood.These locations have been painted three times already with same results. we have sanded to bere fiberglass, reprimed and repainted but problem still occurs. Paint is Dupont as well as primer. We're pulling our hair out trying to figure whats wrong. Paint rig is HVLP with gravity feed. Rest of the car looks great. Help needed ASAP. Desperate.
Thanks Bob  

it really truly sounds like something is in the fiberglass...  grease, oil, silicone, wax, mold release...  i take it the spots are always in the same place...   it might be soaked in or below the top layer...   there may be a better sealer available...  

this might be a time to call the paint store and have a dupont rep stop by...  they might be a better help first hand,,, eyes on the problem...

to get effects in house paint like crackled paint... you paint over a fresh coat of horse glue....  this is the dryed up paint effect that the movie and tv people do..

sorry i dont have more info for you....  

I have had paint wrinkle problems before several times. I don't know if your problem is the same as mine was, but my problem was that I was putting on paint too heavy and the top of the paint starts to dry too fast,  shrinking and making a wrinkle. I have only had this problem in the summer when it was very hot and the paint was drying too quickly. I usually sand the wrinkle out and lay down several lighter coats and wait longer than normal for each coat to dry. If I remember right, I think I have only had this problem with spray can paint. But you never know.  

how long has everything had to dry? What kind of primer are you using?

when you sand the primer down, are you sure that there are no shiny spots underneath the primer still? If you dont have the surface under the primer sanded properly, if there us an unsanded portion of the paint under the primer, it makes a prime area for the paint to lift when you spray on top of it.

Are you spraying the paint overly wet? What reducer are you using with the paint? Is it Chromabase? Nason? Try to 'bleed' the paint onto the affected areas before really spraying it wet. that basically means spray it lightly in the area in many thin coats before applying it normally to help isolate any issues befor ethey happen.

Wrinkling is typically the result of a solvent attacking a substrate. It will usually happen over surfaces that are either too fresh to paint over, or improperly prepped surfaces. like i mentioned about the primer over improperly sanded paint, that edge allows solvent to get underneath the primer where it can move the primer on the surface, which creates a wrinkle.

When you shoot a paint too wet initially, the same thing can happen but its in a different way. The solvents in the paint overly saturate the substrate and allow it to reflow. again, the movement is shown as a wrinkle in the finish. That can happen with paints that are too fresh to paint over as well, and with laquer style primers.

give some more info, and give it a shot with the bleeding technique. Chromabase tends to respond well to it. Worst case senario, if you are using Chromabase, they also have a non penetrating basemaker that you might want to try out too. I dont remember the part number, but the paint store should be able to get it.