The SS hood I purchased for my '69 Chevelle is coated black as are most repro parts. This one is mfg. by Dynacorn and on their website, "Joe Parts" answers your questions about their parts. His answer to my question about what to do about the black coating was; sand it off, bead blast, whatever, but get it off before painting because it is not paint or primer, it is a rubber coating known as EPDM that is there for corrosion protection only. I also asked about the underside since it looks great as it is and he said the same thing, but added; leave it on if you like but we're not responsible. This would probably be of interest to anyone who has purchased these parts, and I'd like to know if anyone has just left it alone and had any time to tell if it's held up? Besides looking original (for now, anyway) it would be a time saver not to have to sand all those ribs to prime and paint. Anyone have any input on this?
Thanks,
Rich

Well, Id ask WHY "Joe" suggests to remove that coating? That black primer if its an true EDP "electrostatic deposition primer" then its full of zinc, zinc protects metal.

Factory OEMs dont want you remove that black coating as it makes for a GREAT base or foundation for the paint system.

To check if its true EDP primer take a cloth and soak it with a strong solvent like lacquer thinner. Hold that rag on a spot for awhile then rub it around. Remove rag and see if any of that primer NOW appears on the rag. If you see black on the rag you NEED to remove that coating, as its a 1K product.

If NO coating appears on the rag then all you need is a scuffing and apply your paint of choice.
I would not leave that coating uncoated thou. Overtime it can fail if left exposed.

If you want it body color just scuff with a red scotch brite pad seal and paint. Or if you prefer the flat black look Id spray on a good 2 coats of epoxy primer.

If I ordered parts from some place and they told me the coating was rubberized and it needed to be removed they WOULD be getting their parts back.

Would Dynacorn be responsible if you did remove that coating and it started to rust?? :rolleyes: :rolleyes:

Sevt, I didn't realize the trade names for those two coatings looked so similar. Electrostatic Deposition Primer (EDP) and Ethylene Propylene Diene Monomer (EPDM), but they are two very different things. The latter is used for roof coatings and molded rubber gaskets, so I understand why Joe Parts says take it off. I plan to do the laquer thinner check, but I will also sand off the outside before priming and painting. I was thinking that since under the hood would not receive much U.V. that it may hold up without having to be sanded off. Maybe a clear coating? That is the thinking behind using epoxy primer (low U.V.exposure under the hood) b/c it would never last if unprotected by a good coating of paint on the outside.
If you did send the part back, you would probably find yourself repurchasing it since, according to a long-time salesman at our site sponsor, Ground-Up, one manufacturer (China) makes ALL of the SS hoods for '69 Chevelle's, and I'm sure they put the same coating on them regardless of who ends up disributing them with their name on it. Makes sense to me, why would more than one stamper want to tool up for the same part and dilute an already limited market?
Their guarantee? I'm sure you're right, you're pretty much on your own either way!
Thanks,
Rich

Originally posted by RT:
Ethylene Propylene Diene Monomer (EPDM), but they are two very different things. The latter is used for roof coatings and molded rubber gasketsBoy is that a NEW one to me!!!
Ive ordered ALOT of stuff from goodmark for my stuff and never seen such a coating on other aftermarket parts for collision jobs

Here is my most recent expierence. New Goodmark hood - Paint shop sanded the black coating that was on the hood, primed it sealed it painted it, we layed the stripes, cleared it came out perfect, only for the paint to lift in a few spots between the black stuff from Goodmark and the primer sealer he put on. Wound up stripping the entire hood down to bare metal and doing it all over again. Play it safe and remove the coating.

Rich

I guess ignorance is bliss. I assumed it was E-coat on my replacement inner fenders. I simply scuffed them with a scotch-brite, sealed, and painted. Eight months since painting and they still look great. Was going to do the same on the hood and fenders but now you got me worried.

Trooper

This is an issue that just seems to get glossed over (pardon the pun) by the resto suppliers. If you don't ask, nobody offers the information, and even if you do ask, quite often you're given incorrect information. I personally think that the manufacturer, the one who is applying the stuff, should prepare a sticker with prep guidelines plainly spelled out and attatch it to every part they ship. This would be a simple step and could save alot of time, effort and expense on our end.
Richr, I'm curious, how poorly was your hood sanded? I DA sanded my deck lid (Dynacorn also) with 80 grit until it was about 95% off. Slight remnants remained even though it was totally sanded over the entire surface. I've applied DP prime and K-36 hi-build primer. Now, I'm wondering if I should go back to square one before I send it to the painter. Like I need this! :mad:
Rich