paint help

[chatcher]

i have been working on a track bike of mine this week with less than anticipated results i am a diyer and this is my first crack at painting two of the five pieces i am working out have turned out great the other three well............

i went to the local body shop supply and told the guy at the counter i wanted to paint over the spray can paint job i did on my track bike with a bc cc he said wet sand the paint that was on there and apply the base when i did the beginig of the first coat it instantly looked like crackle paint so i called down to talk to the guy but got another who said i needed to resand the bodywork smooth and apply epoxy primer i did this with some what of the same results but not as much crackling then after the epoxy dried i sanded down the few bad spots that were left and hit it again with another coat of primer at which point it looked as though everything was ok i let the 2nd coat dry for about two hours then began appling base again only to have the crackling appear again but not as bad as the first time and not on every piece the upper and front fender look spectacular but tail tank cover and lower are crackled again i am gonna call this fella back again tomorow when the store opens but am looking for a second op

primer base and clear are all ppg and state on the worksheets they gave me to be compatable did i not let the epoxy dry long enough or should i have tried to completly strip all the remnants of my spray can job. if so what can i use that wont hurt the fiberglass ,and should i be worried about future prob with the two pieces that look good thanks for your time and any addvice will be greatly app thanks in advance

[KiltedBanshees93GT]

I'm no paint guru, but what it sounds like to me is that the original rattlecan paint is incompatible with the stuff you're using now. you said that you were using an epoxy primer at least for the second and third base coat, is that what you used for the first coat as well?
What kind of spray paint did you use for the old paint?
Basically the purpose of primer is to "grip" the piece painted and then give something for the paint to adhere to. It sounds like the primer isnt able to grip the old paint properly, causing the crackle effect as it dries.
Also, any type of residue left on the piece can cause the primer to loose adhesion. Were the parts that are giving you trouble frequently subjected to oil/gas or other fluid spills?
If I were you I would carefully wet sand the piece down to the original primer. Once youre down to the primer, I would wash the piece with a mild dish soap to make sure all oils etc are removed, and then air dry the piece, and and re shoot it.
Hope this helps.

[Hethj7]

When you are painting parts like that you need to use a flex agent additive. Those plastic parts like on the bumper of the Mustang or on bikes will flex and cause the paint to crack.

I am not sure if the paint will work correctly with your original spray job, but I know when painting parts like this the flex agent is needed to get good results. It may not be the complete fix to your problem, but it should help.

[chatcher]

thanks for the replys i went ahead and sanded back down to the gel coat and everything worked great and i knew about the flex add for the clear thanks

[Hethj7]

Cool. I hope it works out for you this time around.