Im not a hotrodder but seem to come across this forum a lot so id thought id ask here for some advice.
Im having some problem with the paint chipping off, im using PPG DP40 primer and PPG Deltron for the top coat.
The primer seems to be splitting apart as the paint chips have the primer colour on the under side of them and the metal still has a layer of primer on it, I have been spraying some test bits of metal until I get this problem sorted as itís a pain in the backside to sandblast down parts because the paint wont stick.
The total thickness of the paint is about 4mill (0.1mm) measured with a micrometer, I spray on 1-2 layers of primer, 15 or so min later when the primer has gone hard to the touch I spray on 1-2 coats of deltron, the temperature has been pretty cold outside lately but have been warming the parts up with a heater before and after painting to try and sort this problem out but I see no difference with the heater.
Could I be spraying the primer on a little thick?
See picture, paint has been scratched off with a flat head screw driver and plastic pen.