I am trying to overlay carbon to some bumper pieces but I just realize epoxy do not bond to polyurethane parts, anyone got any tricks how to do overlay on polyurethane bumper pieces?
The only thing I’ve done is to use 50 grit sanding discs and really scratch it.
I would use my dremmel to make small holes on the part so that epoxy “locks” in place when cured.
a primer may work
primer sounds like a good idea, would arosol primer work?
Try to make sure that you use a good 2K primer, not the real cheap stuff.
2k primers are generally an alternative to epoxy primers. And on poly it is recommended to both use an adhesion promoter like bulldog both added to the primer and sprayed on a prepared surface. Warme water rinse, then 400 grit scuff, bulldog, prime.
That is considerably much more work, time and material for a questionable bond to a laminating resin.
Scuff san with 80 grit and use a high strength adhesive to glue dry fabric on the part. Then begin saturating the cloth with resin Sand and clear coat.
2k and 1k primers also flake and crack. They also dry very brittle unless you add flex additives.
Loc-tite 2 part epoxy will work just fine on a roughed up polyerathane surface.
3m scotch weld will work also.
I have used both on polyurethane.
Drilling small holes works good to and prevents delamination if you were to maybe bump something. I would suggest a 1/16 to 1/8 in pilot holes or number 50 or 40 drill.
Dallas,
What do you mean when you say, bulldog?
Zach
Bulldog is a adhesion promotor specifically for plastics. It’s what you use to paint plastic bumpers.
But even with that you still scuff sand.
Bulldog comes in spray can or in quarts from your local body shop supply store.
It’s just a tack additive for primers or surface prep.
Adhesion promotor, primer. If your primer is gray, then wet sand the primer, paint black, and then clear coat. The clear coat will provide a nice cured surface to spray on resin to then overlay onto. Thats how we do it. The black paint is to create a black background.