Originally Posted by chris slee
all 3800 valve cover are the same plastic materiel and exstensive heat will warp them or milt them, like tom said there are some nice aluminum ones or paint them urself the cheasest way of doing them
not plastic, smc composite. smc is fiberglass (choped, woven, random roving ect) and Thermosetting polymer. Its not thermoplastic. If it were it would have the markings like every other plastic piece on your car to identify it. The newer s3 might be plastic, Idk and Idc.
practiced with some junk yard valve covers, kept the temps below 350degrees. lower temps longer cure times. But they will need to be outgassed, experiment. There are too many variables with ovens and element placement.
The valve covers will need to be warm for the initial powder to stick. Sometimes referred to as hot flocking. Be careful. Practice if you have doubts. The chrome powder applied much easier than the candy; which required a few re heats to get an even coat.
When I put the parts in the oven, I waited for pmt to reach 200 then went to 250 and waited for flowout and let it sit there for some time, I'd say 30 minutes. Then went for cure temps. Keep a real close eye on the stuff. Can't say how long I waited for cure. hour or so before I lost patience.
Want to test for proper cure? Scuff a section of the baked powder and rebake. Scuff smooths and shines back? (if you used gloss) You didn't get a proper cure.
Did one chrome for a friend,didn't notice warpage and there are no leaks. Did another one for my car, tried a candy copper over chrome to match my paint. Forgot to outgass so a few bubbles. Long term effects? I'll find out.
Go ahead and spend the money on the aluminum ones if you like. Paint the stockers if you want. I have the means to powdercoat and powder is real cheap. So that'* what I wanted to try and share the info and results with those that may be interested.