Time to top coat

Dean

Promoted Users
Ok i have a few parts n pieces on this old car im doing.
Works all done on them and ready to prime. Plan is to epoxy them and paint. Question is how soon can we paint over the epoxy. Tech sheets shows timeline as sealer and 7 day no sand window but nothing on how quickly it can be painted over.
 
Huh. Searched forum and see a few ask this and not 1 got answered. Most was about more primer. As sealer says min 2 hour and also says reduced sets up faster, so non reduced id assume more than 2 hours.
Were waiting 48 hours.
 
Ok i have a few parts n pieces on this old car im doing.
Works all done on them and ready to prime. Plan is to epoxy them and paint. Question is how soon can we paint over the epoxy. Tech sheets shows timeline as sealer and 7 day no sand window but nothing on how quickly it can be painted over.

I normally wait 24 hours after spraying 2 coats of epoxy. That is keeping it a 70 degrees.
At that point I can do pretty much anything with it.
 
I normally wait 24 hours after spraying 2 coats of epoxy. That is keeping it a 70 degrees.
At that point I can do pretty much anything with it.
Ya is my usual as well. Just thought id make sure being newish product to me. 48 to be safer lol.
 
See my sig for a link to the tech manual. The epoxy entry is extensive, and a lot of the best info is near the end of the entry.
I have a hard copy of the tech book. Isnt in there that we could find. Only the sealer timeline and max time used as epoxy. Not the min time.
 
Two coats of unreduced epoxy I usually wait minimum of two hours. I usually wait 30-45 minutes between first and second coat of unreduced epoxy. Then minimum of two hours after second coat of epoxy. Lot of it has to do with how wet epoxy is sprayed and temps.
 
It's not typical to spray 2 coats of unreduced epoxy and topcoat directly over that, in my experience, but the tech manual definitely says "overnight" for this procedure.

I don't do this because of the texture and trash that will almost certainly get into two full coats of epoxy. After 48 hours, two coats could be lightly sanded, then an epoxy sealer coat of 50% reduction could be used to fill scratches and cover any sand-throughs. 50% reduction can then be painted as soon as a half hour later, depending on temps.
 
I just have few small parts to paint. Just wanted to epoxy and paint. But wanted touch more build than reduced as sealer.
They were in old primer so just want to coat that and carry on.
 
I think the answer is "overnight," though now some of us will be seeing warning lights about priming over some other primer that we don't know anything about. If that old primer is reversible or prone to swelling, all bets are off.
 
Its 2k primer put on by cars owner, guy i work for. Been on for 20 years and no issue. I trust it. Hasnt been used in 20 years or more since it got bashed up
 
Oh-oh! 2k primer is very susceptible to contamination. I would guide coat and block sand to remove at least the top layer of the 2k before shooting anything over it. Remember your paint job is only as good as the foundation it is sprayed over.
 
It's been in primer for 20 years?
Ya. He went into a gaurd rail on way to a show and did the repair and primed but its sat in storage since.
Tine to get all his toys back alive now. He covered the 2k in some blk laquer primer but i took that all off abd into 2k a fair ways.
 
Oh-oh! 2k primer is very susceptible to contamination. I would guide coat and block sand to remove at least the top layer of the 2k before shooting anything over it. Remember your paint job is only as good as the foundation it is sprayed over.
I went in almost through. And some spot i did have small repairs.
 
This is just my opinion based on experience, but I would strip anything that was sitting in primer for 20 years. No one has ever wanted to hear that, though. Thing is, if it fails later due to something coming from below, how do you know what caused it? It's a lot harder to tell if there was anything questionable left on the part. Fresh epoxy on bare material is the way way we start at our shop, doesn't matter if it was the best primer shot by the best painter in the world. Been bitten too many times.
 
This is just my opinion based on experience, but I would strip anything that was sitting in primer for 20 years. No one has ever wanted to hear that, though. Thing is, if it fails later due to something coming from below, how do you know what caused it? It's a lot harder to tell if there was anything questionable left on the part. Fresh epoxy on bare material is the way way we start at our shop, doesn't matter if it was the best primer shot by the best painter in the world. Been bitten too many times.
Owners call not mine. Id have redone whole car if was mine.
 
Its 2k primer put on by cars owner, guy i work for. Been on for 20 years and no issue. I trust it. Hasnt been used in 20 years or more since it got bashed up
Ya. He went into a gaurd rail on way to a show and did the repair and primed but its sat in storage since.
Tine to get all his toys back alive now. He covered the 2k in some blk laquer primer but i took that all off abd into 2k a fair ways.

You do realize that 2K urethane is porous right? 20 years old, I can guarantee you that there are speckles of surface rust on the metal underneath that primer (at the very least) . No way in hades I'd spray over 20 year old exposed primer. Inside or outside storage would make no difference to me.
To each his own though I guess.
 
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