Painting ground effects (Page 1/1)
creaky78 APR 18, 09:23 PM
The paint on the ground effects on my '87 GT is pretty well chipped at the top edge in several places. I thought I would sand the chips, use filler to level things up and repaint. However, when I tried to sand, the paint is just flaking off, I can even pop off chips of paint with my fingernail. Obviously I need to remove the panels, strip them and start from scratch. I have repaired and painted fiberglass on the Mack trucks that were used in my business but I'm not sure what kind of plastic the ground effects are and need to know if there is anything different about preparing and painting them as opposed to fiberglass. All help appreciated.
IMSA GT APR 18, 10:00 PM
Stick to wetsanding the old paint off. By the sound of it, it sounds like someone already used spray paint but didn't prep the plastic before spraying which is why you are able to remove paint with your finger nail.
Gall757 APR 19, 10:57 AM
+1

Do not use any kind of stripper or solvent. Maybe this has been done already, which will mess up a new paint job.
creaky78 APR 19, 12:23 PM
I don't believe that stripper has been used as the exposed bare plastic shows no signs of damage, not even sand scratches. What kind of plastic is this stuff?
Gall757 APR 19, 02:26 PM
TPO

[This message has been edited by Gall757 (edited 04-19-2020).]

creaky78 APR 19, 05:13 PM
Thanks Gall757. So I should use an adhesive promoter and do the usual 1K basecoat and 2k clear?

[This message has been edited by creaky78 (edited 04-19-2020).]

Gall757 APR 19, 07:00 PM

quote
Originally posted by creaky78:

Thanks Gall757. So I should use an adhesive promoter and do the usual 1K basecoat and 2k clear?




There are many threads on this subject, but the consensus is: Skip the adhesion stuff and spend extra time on prep with 220 grit. Thin coats are better than thick.
rogergarrison APR 22, 06:40 PM
I believe the parts are thermoplastic, not SMC or Fiberglass. ABS plastic never needs any kind of primer...just scuff sand and paint. ABS is mostly used in aftermarket parts.

NEVER use any kind of stripper on ANY kind of plastic parts. Ive seen guys total a Corvette body using stripper, EVEN when it says safe for fiberglass. All you can do with it after is junk it and find another one.

Proper sanding is always best with 320, 360 or 400 grit...not necessary to wet sand, dry is fine. Adhesion promoter is primarily meant for soft plastic/vinyl like door panels, armrests, etc. No need for it on any outside body parts. Just sand, prime if needed, basecoat and clearcoat (or single stage).

Ive been professional body paint/restorer for 55 years.