I'm painting couple of pieces of metal, and while the paint was drying it started to crack. What causes this cracking? I sanded the metal with 400 grit sand paper, washed with a degreaser, primed with a self etching primer, then paint. What am I doing wrong?

Thanks,


Paul

 

the paint may have not been mixed well enough, or it was put on too thick...

 

you put self etch primer over old paint? or bare metal its only supposed to be over bare steel(no filler nor primer) your supposed to top coat self etch primer with a 2k sandable primer

has the car been painted with a cheap lacquer paint in the past or lacquer primer?
the solvents from non lacquer paint will soften lacquer and make it cause problems

 

oh yeah pics please

 

Sounds like it's lifting. Which means that there's some sort of contamination or you're putting too much material on at once.

 

paint when it does that is called "checking"= means you most likely have applied paint over top a non compatible paint..meaning and don't quote me..but it goes something like this...you can apply enamel over top laquer paint but not the other way around.....but..I may be wrong on the two as it may be the other way around...either way the paint is lifting and surface needs to be stripped and proper surface prep with proper primers needs to be applied

 

Thanks guys. I guess I'll have to spray lighter coats.

 

What brand of paint are you using?

 

I think self etching primer has a bit of acid or something in it and if you didnt top coat over it with an epoxy or 2k primer/surfacer it reacted with your paint.

Ive never used self etching primer just epoxy and primer/surfacer so I may be wrong.

 

Did you spray the primer on bare metal??