I am preparing the car for paint and am getting ready to shoot the first coat of epoxy primer. I have sanded the panels and made repairs and modifications. I planned on shooting the epoxy over the sanded panels. Should I use adhesion promoter before I shoot the epoxy?

Thanks
Frank

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88 GT 5 Speed Black with gray interior
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"Real integrity is doing the right thing, knowing that nobody's going to know whether you did it or not."

If you have bare plastic showing on the bumper covers you should shoot those....but I think the rest is okay.

If you are not in a hurry, wait for comments from the pros...(we have a few on this site who comment often).

Its been my experience they are all a waste of time on any hard surface. That stuff is for painting new soft interior panels like dash and door panels. It dont make paint stick any better on a body part. Ive tried them all. I even tried one that was supposed to make paint stick to chrome...specificly made for that. Followed instructions to the letter. Next day almost all the paint flew off when I washed it. If you want to use it, by all means go for it. Its worthless snake oil as far as I can say. I know dealerships that use it like on new bumpers to save the labor of scuffing the part. Spray promoter, spray paint and send it out the door. A few months later, the car shows up here with all the paint peeling off. I take it to a power wash and take the rest off and repaint it after its scuffed. I did a Scion XB bumper after the dealer redid it already 3 times for a girl I know. She took it to the dealer because she wanted a professional job, lol. Now I do all her families cars. I cant even count how many Ive done over.

It has been my experience that, any sanded surface (roughed up enough) that is perfectly CLEAN ( washed with wax & grease remover) all you have to do is prime. never seen any adhesion promoter actually work, not even the stuff they used to used for door jams. rough enough to get a "grip" & CLEAN is the ticket. if the surface is "slick", chrome, glass etc, if you don't sand it, it won't stick.

Yeah forget about adhesion promoter. The epoxy will stick better than anything else (if you're using PPG DP epoxy primer).
~ Paul
aka "Tha Driver"

Custom Fiberglass Parts

quote Originally posted by Lou6t4gto: It has been my experience that, any sanded surface (roughed up enough) that is perfectly CLEAN ( washed with wax & grease remover) all you have to do is prime. never seen any adhesion promoter actually work, not even the stuff they used to used for door jams. rough enough to get a "grip" & CLEAN is the ticket. if the surface is "slick", chrome, glass etc, if you don't sand it, it won't stick.

You cant beat cleaning and sanding. Most new 'hard plastic ' parts I get new come with paint instructions from the factory. Those are ABS and most thermoplastics. The directions generally say to scuff and paint directly. Some even specificly say ' DO NOT PRIMER THIS PART ' on a sticker attached to it. Jaguar and BMW bumpers come to mind right off the top of my head. Chrysler hard plastic bumper covers have no primer either, just base and clear coats.

seems to me , I remember about a decade or so ago, some makes (can't remember which ones) did not use primer on their hard plastic bumpers, & a few years later were peeling. Maybe they've finally perfected a new method. the only paint I personally have seen painted on Plastic and absolutely doesn't let go is "Fusion".(Amazing stuff). I'm sure if they Do Say "don't prime it" there must be a reason.

Urathane (soft) bumpers are not the same as Thermoplastic or ABS plastic (hard). A lot of new cars since the 80s, especially back then, with flexible bumpers werent even painted. They were dipped in a special vinyl coating. That was the reason on those cars never matched the car body perfectly. Fiberglass is different from both. When I did all the paint work for Funtrail Conversion Vans in the 70s, they installed fiberglass fender flares and they took a beating with primer and acrylic enamel. They didnt have urathane paint then. When they started installing ABS flares, I just sprayed color on them and problems all went away. Back then, they didnt even have a clear coat.

quote Originally posted by Lou6t4gto: It has been my experience that, any sanded surface (roughed up enough) that is perfectly CLEAN ( washed with wax & grease remover) all you have to do is prime.

+1, very true.

I had a painter tell me once that the urathane bumpers (when bought new) have to run through a few bake cycles because they leech chemicals... then you clean ,sand,epoxy prime, base and clear. If you don't then the first time the car is baked in the future the paint will pop.

I wonder if that is not why our quickie paint job (by previous owner) on our used civic has had issues. Seems the car had its nose smashed and was then sold and bought by a guy to do a quick flip. He replaced and repaired the front end, but had no paiont booth. Got a new bumper, but did not bake it. We got hit in the front and the insurance went to repair the damage and as soon as the car was baked the paint was flaking off the un repaired areas. They could not explain it, but if chemicals were leeching, then those chemicals would pop the paint off?

In teh end the insurance company had to get a new bumper for us and redo the paint job cause it was continuing to flake off even after their repair.

Any truth to this?

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Rescued & resuscitated 1984 Indy Fiero SE Pace Car Replica #770 presently reversibly modified!
SE: Stormtrooper Edition


Everything is the Previous owners fault

Ive never heard that. I install new covers all the time. Most new ones I get just say clean, dry, scuff lightly and paint. I have to fix botched ones all the time too. Its from lack of sanding shortcut. Baking only makes it dry fast so they can get another car in the booth. They make more money doing 5 cars a day than 2.