Epoxy over e-coat

I've got a 92 Chevy pickup whose front end got banged up a while back when a guy decided to do a u-turn right in front of me. I replaced the left fender and hood, and went ahead to repair the rust on the rockers, cab corners, and rear wheel arches thats typical on all these trucks. Going to pick up some SPI epoxy tomorrow from the local dealer to prime the rust repairs. Due to some other commitments, it'll probably be 4 or 5 months before I'll have time to repaint the truck, so I'm wondering if I should go ahead and prime the new fender and hood at the same time. Both those parts have the e-coat on them now, and it doesn't look like something that would be particularly durable if outside for a few months. Thanks in advance for any advice.
 
I've seen the e-coat that you couldn't get it off with a chisel (well, almost...) and seen it with nasty, rusty metal underneath. You get to decide what prep you want, I'd strip the e-coat to make sure I had good adhesion of the Epoxy to bare, prepped metal. If this is a daily driver that you'll get rid of in a year or 2, you may look at it differently, but then that becomes a slippery slope as well..
 
OE parts have high quality e-coat that is best well scuffed with a red pad and primered over. Aftermarket parts can be a very different story, though the certified parts I've seen lately tend to be run on a high quality process as well. You need to use your best judgement. I think parts that are sold out of restoration parts suppliers tend to have questionable primer.
 
Thanks Robert. I'm 69 and have owned the truck since new. I do plan to keep it as I don't have any desire to own any sort of new(er) pickup that costs half as much as a house and is the size of a small school bus. The truck is a short bed standard cab 4x4 that's never had so much as a minor ding in the body prior to this, and I don't want to do any half baked repairs on it.

The patch panels I've installed are from the same source as the hood and fender, and the e-coat on them sands off easy with 80 grit on a palm DA. I hadn't really thought about it, but your suggestion to strip it off seems like time well spent. Thanks for your input, and thanks for your posts on other forums showing your spot and grind method for welding in patches. One of the most useful things I've learned via the internet.
 
Thanks Crash. All the parts are certified aftermarket and the e-coat is slick and has full coverage. There's a place about 15 miles from me where a guy runs a truck only junkyard and has a 15,000 sq ft warehouse stacked to the ceiling with aftermarket crash parts for pickups. The parts I bought were a perfect fit, and I guess he figures the way to sell to body shops is to stock good quality parts.

I do think I'll go ahead and strip the e-coat off per Robert's suggestion so there's no question as to what I'm putting the epoxy on. I'm about 3/4 retired, so that'll give me one more thing to keep me occupied :)
 
IMO after years of working with OEM and aftermarket parts, there is a difference in the coatings. If we are talking restoration,not collision, OEM stuff would be the only stuff I would consider leaving on a panel. Any aftermarket panel I would/will strip. The coatings are not the same. I can't speak to what the diffeence is but there is a difference and the aftermaket stuff is inferior to properly applied epoxy.
 
If it fit decently you got lucky. Aftermarket fenders for Chevy/GM trucks of that era have always been a PITA to get to fit, and get all the components to fit to the fender. CAPA certified doesn't really mean much IMO. It's a term the Insurance Companies made up to justify putting aftermarket junk on nearly new cars. That's all it means. Would you be satisfied with CAPA certified stuff on your 2019 or 2020 truck? That's why they made up that nomenclature so they could do that and tell the customer that it's certified.
In reality there's OEM and then there's Taiwanese Aftermarket. It all comes from the same one or two different sources in Taiwan. And even if it fits decent, nearly all aftermarket that I've seen over the years are made of inferior grade steel. That is a fact.
Like a lot of the guys here who have worked, or still working collision and care about what we do, I hate taiwanese aftermarket parts. Nearly every collision guy will tell you the same. Sorry for the rant but there really isn't anything positive about Taiwan aftermarket other than the price.
 
For the guy off the street like me, the dealership price for a hood and fender was $850 more than aftermarket, and they wanted another ~$100 freight on top of the list price since they supposedly get parts like that via motor freight. With sales tax, over $1000 difference, and that was more of a premium than I was willing to pay.

That said, to give a little insight to this local dealer, I shopped them when I was interested in buying a new 08 Corvette when the economy had gone to hell and no cars were selling. They had one in the showroom that, according to the inspection sticker in the window, they'd had for 8 months. Their "best price" was a thousand bucks off of a $58K sticker. Drove 75 miles down the road and bought one the same day for $17K off the same sticker price. After we'd made the deal, I mentioned what the other dealer wanted and the sales manager just shook his head and told me one reason they were able to get their price down was $4000 in factory money coming back to the dealer on any new Vette sold at that time. All that considered, an honest dealer might have been $500 less for the hood and fender.
 
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