Adpro prep advice

[ct71rr]

Hi all, I’m going to spray some epoxy on the plastic hood inserts on my ‘71 Road Runner. I have already sanded off numerous coats of paint/primer down to the plastic. I used 220grit by hand. I believe my next steps are to sand with ScuffStuff and a scotchbrite then spray the adhesion promoter then epoxy. Is 220 enough or do I need to go more aggressive before the ScuffStuff? And, are my steps correct?


These are the inserts:

A bunch of layers on them:

Thank you

 

[Chris_Hamilton]

First thing to do is take a sliver off the backside and put it in a glass of water. If it floats you need promoter, if it sinks you don't. I don't think it's going to need promoter as most plastics were urethane back in the early 70's.

So why not just use it anyway? If it doesn't require it, the adhesion you when using promoter is less than what you would normally. So test it and let us know. Then we can advise on how to proceed.

 

[ct71rr]

Thanks for the response, Chris. I cut a small piece off and it sunk immediately.

 

[Chris_Hamilton]

No need for ad-pro. I would try to strip it as best as possible with 180 grit then epoxy. 220 might be coarse enough IDK. I'd feel better with 180. No need to scuff or anything else. Just clean with W&G remover then epoxy.

 

[ct71rr]

Will do. Thank you for the response, much appreciated!