Quote:
Originally Posted by germaneighter
Does anyone here have first hand experience in painting a raw urethane bumper cover?
What did you do to prep it?
Did you heat it to sweat out any release agents?
What, if anything, did you wipe it down with prior to primer?
Did you use an adhesion promoter?
thanks
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Am not a professional autobody guy, but I painted a urethane front airdam once, which was initially new and unpainted. Although this was 15 years ago and I can't remember all details of my products used and process, I basically followed the instructions (more or less) of the local autobody supplier. I'm pretty sure I used PPG paint, and I seem to remember using some of this:
http://us.ppgrefinish.com/getmedia/0E569BD8-6F4B-433E-9937-D5E35B5F28C6/09/p-128-dx369.pdf
I don't remember heating the bumper before painting it, but sounds like an interesting idea I haven't heard of before.
I seem to remember using a product called "flexible bonding clear" which sounds like it would have been an adhesion promoter.
The paint I used for the rest of the car had a 2-part clearcoat called concept 2000, so that's probably what I painted the bumper with also.
It turned out OK - I think the color I used (yellow, non-metallic) needed a lot of paint/coats for good coverage. Even with the flex additive, it seemed to eventually get a bit brittle, and cracked/peeled in some places where I took out some traffic cones at pretty high/hard speeds (autocross competition). So if I could do over again - I would be very focused on trying to get as good adhesion as possible, and using something with flexibility if possible (maybe by only coating as thinly as required, especially on the clearcoat). It did take a lot of abuse before it cracked, though. I eventually added a metal reinforcement along the bottom edge of the airdam so it wouldn't flex as much when I hit cones, and then I think it didn't crack any more since then. That stopped the cracking.
It probably wouldn't have cracked at all if I wasn't taking out traffic cones with it at high speed.
