This is my second full respray in 8 years(done at home by professional)Replaced whole front bumper of my 85 camaro with GM original bumper plastic/fibreglass type - it came yellow in appearance

Used chromabase (DUPONT)paint system including heavy duty primer - local paint shop recommended spray can bumper prep for flexible type surfaces - we did

Paint held on for four months five tops - now you can flick it off at will and my pride and joy looks as if its has bad teeth - the worse part is that primer and paint are coming off - so its yellow patches again

I am not in the US - and I would want to use my left over paint if I am doing the bumper over

So what preps are recommended over there by you guys?? and what's your advice to stop this problem once and for all??

Would I have to have a special paint mixed to my color code instead for the bumper???

You might want to remove all the paint and use a good epoxy primer that wiil bite into the plastic better.

Was the bumper allowed to gas out before you painted it...I have been restoring a car at my buddies bodyshop and whenever he receives a bumper he heats it in the booth for about and hr..He tells me it helps the bumper gass out..Otherwise the bumper will atempt to gas out and lift the paint over time...He also uses Spies&Heckler paint system...Not sure of the # but they have a great primer for fex bumpers...Good luck

The heat thing is true, you can also use a cleaner and wash down the bumpers when new. The problem is either 1). the release agent (used when manufacturer moded bumper) or 2). some types of plastics don't hold paint very well.
A good cleaning before its scuffed, or heat will usually take care of the release agent.
If the problem is the type of plastics used in the bumper it can be a little harder. Our paint (PPG) has a plastic parts adheasion promoter that should be used on ANY plastic or rubber parts that don't have a factory primer on them. This stuff is not a primer, its almost a clear pink color. It actually softens the plastic (or rubber) to make it accept paint or primer. Its sprayed on, then it must sit for 30 min. before sealer or primer are applied.
A good primer (like epoxy) still won't stick to the "nasty" plastics.
Austin

Regular primer won't last, even "heavy-duty"; you need a special primer for urethane parts that includes an adhesion promoter and a flex agent. All the major paint manufacturers have it, but you have to ask for it specifically. Nothing else will last on urethane substrates. Without the adhesion promoter and flex agent, it comes off in big hunks, as you have found out http://www.camaros.net/forum/frown.gif .

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JohnZ
'69 Z28 Fathom Green