Is there anything special I should do? I am sanding the entire car down to bare metal to get it ready for paint. I have heard some say it is tough to get paint to stick to the urathane bumpers. Should I not strip them down? Is there a special primer I should use on them if I do?

 

You need to ask the manufacturer of the paint system you will be using what prep steps are needed.

I just got done painting a new, bare bumper cover/front facia for a Pontiac Grand Prix.

The first step was to use a grey 3M pad and scuff the surface until it was no longer shiny. Then wash it with hot, soapy water- Dawn dish detergent works well, something that will remove any grease or oils from your hands. Rinse it thuroghly, and dry it with compresssed air.

Then I sprayed it with a coat of adhesion promoter- it is a product made to allow finsh to stick to the surface. Then I used a PPG sealer, 1 coat. Then paint and clear. I used Deltron DBC2000 paint with the appropriate reducer, and PPG's product literature said no adhesion promoter was needed. Your paint system may vary.

Now that was done on a NEW part out of the box. If you have a front airdam or facia from the typical F body that's been rock chipped and repainted at Maaco thriteen times in it's life, you will need to strip it to bare, and probably do some repairs if it has gouges etc. in it.

This is when talking to your paint supplier is very important. The stripper used for metal parts can damage the plastic possibly to the point that paint will never stick to it- plastic is porus, and things like lacquer thinner absorb into it like a sponge.

So as you can see plastic parts need to be treated entirely different from metal. Ever see a thirdgen driving by that has the paint peeling off the bumpers? Probably because they had it sprayed on some $199 special, where no special prep was done.