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MikeyBob 11-13-2011 02:17 PM

Epoxy primer over 400 scratches?
Hi guys, I've been lurking around learning as much as I can, and I finally found a question I couldn't find an awnser to ;)

Anyway, the story, I've got a camaro that I'm trying to repaint. In the end it'll be a dark metallic red (Omni, yes :rolleyes: ) So, I've stripped the car down to metal, sprayed PPG omni epoxy primer over everything, did my bondo work, and now have sprayed on my filler primers: some 2k high build feather-fill and some autobody master 2k build primer. These have been sanded with 180 and then recoated and sanded with 400. Now I know the feather-fill is porus, so I can't wet sand it with 600 before I seal it with reduced epoxy before the base.

So the question is, would there be any problem spraying straight epoxy primer over the 400 dry sanded build primers and wet sanding that with 600-800 a few days after, you know, before spraying a sealer or the base?

swvalcon 11-13-2011 02:58 PM

Why use a sealer just get some spi epoxy and spray a good coat then paint. Works great as a sealer.

MikeyBob 11-13-2011 03:23 PM

I figure I've already got the omni epoxy so why not use it (it'll work as a sealer too) so if I can spray epoxy thinned as a sealer (or just the epoxy) and wetsand it without having to worry about the polyester feather-fill soaking up water that would be great

And whatever my next project ends up being SPI will be the path I go :welcome: haha. I'm actually trying to follow their perfect paintjob

mitmaks 11-13-2011 06:05 PM

I haven't used Omni epoxy so I don't know how thin/thick it is. You're risking showing sandscratches with 400. You could always sand your 2K build primer with 600 and then epoxy it and shoot your color. That's what I would do.

jcclark 11-14-2011 05:04 AM

Spraying epoxy over 400 scratches is pretty safe.
Most painters base over 400 and not have problems.
Epoxy will fill way better than base and cover/fill scratches
way more coarse than 400. I wouldn't want it any finer
than that personally. I have used it over 220. :mwink:

swvalcon 11-14-2011 06:22 AM

If your epoxy wont fill 400 grid I sure wouldn't be using it. You should be able to paint over 400 with at most one extra coat of paint .I do it on use car work a lot. I've used omni epoxy and I wouldn't thin it more than about 10% with a good grade reducer.

deadbodyman 11-14-2011 06:26 AM

Usually the feather fill goes on first then the 2k,I'd use at least 3-4 coats of epoxy to make sure the feather fill is sealed up good then sand with 600 being careful not to sand through then paint,you wont need any other sealer

jcclark 11-14-2011 10:46 AM

Check your tech sheet on the epoxy,
Some recommend no more than 2 coats at one spray session.

skip99 11-14-2011 01:04 PM

I believe omni epoxy calls for acetone when thinning...and yes, 2 coats of omni is PLENTY...

if you have feather fill showing...just spray another coat of 2k primer, wet sand.(400 is fine enough) seal and paint...
the epoxy actually takes 7 days to, unless you are gonna wait (like the perfect paint job) just skip it..

bighotroddin 11-15-2011 04:12 PM

I use the Omni epoxy for dealer on some stuff. Mix at a ratio of 2.1.1. I use DT reducer.

You can do the same thing with the DPLF epoxy to.

jcclark 11-16-2011 04:59 AM


Originally Posted by skip99
the epoxy actually takes 7 days to, unless you are gonna wait (like the perfect paint job) just skip it..

No one waits 7 days to paint over epoxy, in fact, if you do,
you have to sand it again, like the tech sheet says.
(Otherwise you loose adhesion and the paint won't adhere well.)
And that's for SPI epoxy that has a 7 day window.(very unusual)
Most epoxies have only a 24 hr window, meaning, you have to paint over
it within 24 hrs or sanding is required again.
Spray your epoxy, wait till the next day and paint over it,
that's the way it's done. :rolleyes:

deadbodyman 11-16-2011 05:54 AM

No one in the colision biz that is....BTW ,the more you reduce SPI epoxy the faster it cures

skip99 11-16-2011 07:47 AM

those of us who have painted forever all know about the epoxy windows and recoat times,,my point was that he didnt need epoxy beteen primer and base...and since he said he was following the steps in "the perfect paint job" which say to actually wait between coats of everything so there is no shrinkage.. that is what i was referring to...and yes, some people do it this way...usually not in collision shops, but some do..usually on long term projects here like most of us do..

this is what pisses guys off and makes them quit helping... read the YOUR advice, and quit attacking other posts.

shine 11-16-2011 08:09 AM

no problem at all. but i definitely would not skip the epoxy . spray 2 coats and after 24 hours you can wet sand it.

jcclark 11-16-2011 11:57 AM

Correcting bad info like
"epoxy needing 7 days to cure so you'll have to wait""
is not attacking a post. And never meant to be. :)

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