Does anyone know the proper procedure subaru recommends for painting a new oem bumper in raw plastic? Painted it once, and it peeled all over. I wiped it down twice with SEM plastic prep, grey scotchbrited, PPG's DP 40, Sherwin Williams basecoat, and ********** Universal Clear. You can almost peel it off in sheets. I am assuming I didn't get all the mold release off of it. You can see the scratch marks on the back side of the dp 40 epoxy sealer, when you peel it off. Just trying to figure out what Subaru says to do on raw plastic. Or does anyone know who i can call to find out? I will try to call the 1-800-782-2783 number and ask too. I am a painter by trade, but this one has me stumped. Plastic from what I understand is polypropylene. Thanks.

Best bet on that is to contact Subaru or a dealer to find out if there's a technical bulletin or repair map on that. They ought to have the prep spelled out to meet warranty specs.

Chris' suggestion, above, is your best first action, however, my experience is that they'll come back with something like "using appropriate products and procedures as recommended by paint manufacturer".

So you're back to square one. You' re right, it is mould release oil that is the problem. Combine that with a level of porosity in the plastic and the usual procedures don't work. We've had it a few times, usually with body kits manufactured in Asia but occasionally with OEM parts too.

The paint manufacturers are aware of the problem and the major ones have a specific primer and procedure to deal with it. In my case, Cromax, have a product called Universal 2K Plastic Primer (901R/907R). Procedure requires heating to 60 degrees C then wash with soap and water followed by cleaning with an alcohol based cleaner and sanding, not just Scotchbrite. Repeat cleaning and then apply the primer, no adhesion promoter required.

We use this primer on all plastics where there is even the slightest doubt about traces of mould release agent or the quality of the plastic and the same cleaning/prep procedure on all unpainted plastics. If we don't use the special primer then a normal 2K primer will work 99% of the time. Not epoxy. Haven't had a problem since we started doing that.

get a qt of martian senour 6249 plastic adhesion promoter...dont know the number for it in sherwin wash the cover an blow a light coat on it an seal an base clear an you will be done...mechanical tooth means nothing on that cover what you need is a chemical bite think of it like the model glue ya used as a kid or pvc pipe cement they work a bit on the same principle once ya understand that you will never have a peeler again....p.s. makes em easy cheesy...hope this helps bondo

Listen to what ol bondo has told you.You need to use an adhession promoter(not bulldog) dedicated urethane sealer,base,clear=done.Epoxy does not work on bare plastic in my experience.Wash with soap and water first is also good advice followed by the appropriate cleaner,and a gray scotchbrite pad for a new cover.Sanding a new cover will cause more scratches and unnecessary work.Some release agents are waterborne so the added grief of a bake cycle on the bumper is not needed.