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Re: Prep for painting over epoxy primer? Sitting a while
[Re: YYZ]
#1494986
09/02/13 12:09 PM
09/02/13 12:09 PM
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Joined: Sep 2004
Posts: 654
MN
astrobuf
mopar
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mopar
Joined: Sep 2004
Posts: 654
MN
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Self Etching primer would be a waste, it's designed to etch metal to anchor itself. You don't have any bare metal.
I'd call Dupont's Tech Service line and ask them.
Checking a few reference sites, it looks like 7 days is the window. Some manufacturers say sand and apply another coat of epoxy, some say scuff and apply a sealer.
If it was my car, I'd scuff it up with a scotchbrite pad and shoot a sealer before base coating it.
Astrobuf
Last edited by astrobuf; 09/02/13 12:29 PM.
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: azblackhemi]
#1494988
09/02/13 12:24 PM
09/02/13 12:24 PM
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Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
Challenger 1
Too Many Posts
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Too Many Posts
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
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Quote:
The tech sheets for most Epoxy Primers recommend sanding and recoating with more Epoxy Primer after 7 days.
This is right... 
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: azblackhemi]
#1494990
09/02/13 12:48 PM
09/02/13 12:48 PM
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Joined: Feb 2008
Posts: 287
Greenville, N.C.
BarrsRestoration
enthusiast
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enthusiast
Joined: Feb 2008
Posts: 287
Greenville, N.C.
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Quote:
The tech sheets for most Epoxy Primers recommend sanding and recoating with more Epoxy Primer after 7 days.
You can't go wrong doing it this way. Anything less is shortcut. It's not worth risking paint failure/adhesion problems later.
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: BarrsRestoration]
#1494992
09/02/13 01:41 PM
09/02/13 01:41 PM
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Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
Challenger 1
Too Many Posts
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Too Many Posts
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
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Quote:
Quote:
The tech sheets for most Epoxy Primers recommend sanding and recoating with more Epoxy Primer after 7 days.
You can't go wrong doing it this way. Anything less is shortcut. It's not worth risking paint failure/adhesion problems later.
I am redoing a steel tanker truck that I sprayed in 2005. Single stage urethane over epoxy primer. I got lazy and let it sit for weeks and then just scuffed it(epoxy primer) and sprayed the urethane. The urethane comes off pretty easy and has not held up like my other paint jobs where I stayed there(at work) and spray everything wet on wet, like in a 24 hour deal.
Lesson learned.
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: YYZ]
#1494993
09/02/13 04:01 PM
09/02/13 04:01 PM
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Joined: Dec 2007
Posts: 1,572
Jacksonville Florida
elitecustombody
pro stock
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pro stock
Joined: Dec 2007
Posts: 1,572
Jacksonville Florida
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Quote:
Makes sense.
Thanks everyone for the replies.
Looks like I'll scuff & shoot more epoxy when I'm ready to finish the rest of the work on the car in one final push.
Keep in mind that most epoxy primers can be used as a sealer, just add more reducer .That way you're not loading bunch of useless material 
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: jughed]
#1494995
09/02/13 09:05 PM
09/02/13 09:05 PM
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Joined: Feb 2008
Posts: 287
Greenville, N.C.
BarrsRestoration
enthusiast
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enthusiast
Joined: Feb 2008
Posts: 287
Greenville, N.C.
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Quote:
Not to steal this thread, but i'm in the middle of replacing both quarters and fenders with AMD stuff, but will not have the car painted until next spring. I will finish the bodywork before winter and want to cover the bare metal (along with the usual filler) and resume work in the spring...what's the best choice (type/brand) of epoxy primer, and how many coats for now??
Also, does the black coating on the AMD parts need to be completely stripped from the inside of the fenders & quarters?? or can it be scuffed and primered??
thanks!!!!!
"Best" epoxy depends on who you ask. The brand I've relied on for the past twenty years is PPG, the DP line of epoxies. Before that I used Glasurit, a high end European brand. The PPG DP is pricey compared to mail order brands like Kirker, but I like knowing I have a local supplier and regional rep I can call if there is ever a question or problem.
The black coating on the AMD parts should only be sanded not removed, (220 grit is fine) and primed. I prefer to epoxy my new sanded parts also.
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: BarrsRestoration]
#1494996
09/02/13 10:33 PM
09/02/13 10:33 PM
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Joined: Oct 2003
Posts: 1,896
New England
Q5_Ed
top fuel
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top fuel
Joined: Oct 2003
Posts: 1,896
New England
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What is the rule of thumb for sequencing paint/bodywork layers? IF I were to work slowly one area such as the shell. Send to blaster, what do I put on the bare metal first, Etching primer or epoxy? If etching can I later apply epoxy and is it more durable? Advantages to either?
WANTED : ...A New Sponsor or Winning Lottery Ticket
69 A12 road runner ,Q5, post coupe, 4 speed, former Drag car restored to "Driver" condition in the early 90's, Showing some Patina. SS/E Track Record Holder 1980 10.40 @ 130mph
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: Q5_Ed]
#1494997
09/02/13 10:44 PM
09/02/13 10:44 PM
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Joined: Sep 2004
Posts: 654
MN
astrobuf
mopar
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mopar
Joined: Sep 2004
Posts: 654
MN
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Lots of controversy/opinion diversity on this question. IMHO, if you have a clean, just blasted surface, you should not use etching primer, rather, you should use epoxy followed by a 2K primer when you are all done and ready to finish up.
There are many threads on the topic posted at hotrodders.com and the guy I trust the most, deadbodyman, despises self etch primer as a crutch and not a good one at that.
Good luck,
Astrobuf
So, are you really a Rocket Scientist?
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: astrobuf]
#1494998
09/02/13 11:24 PM
09/02/13 11:24 PM
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Joined: Feb 2008
Posts: 287
Greenville, N.C.
BarrsRestoration
enthusiast
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enthusiast
Joined: Feb 2008
Posts: 287
Greenville, N.C.
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Quote:
Lots of controversy/opinion diversity on this question. IMHO, if you have a clean, just blasted surface, you should not use etching primer, rather, you should use epoxy followed by a 2K primer when you are all done and ready to finish up.
There are many threads on the topic posted at hotrodders.com and the guy I trust the most, deadbodyman, despises self etch primer as a crutch and not a good one at that.
Good luck,
Astrobuf
I agree with what you've posted. No need for spraying etching primer over blasted metal. Personally, I don't care for etching primers myself. For some people they have become a crutch for poor metal prep, a substitute for removing surface rust. Also, some etching primers should not be sprayed over fillers or used after etching metal with acid cleaners.
I use a combination of acid (DX579) and blasting, followed with two coats of PPG DP epoxy primer.
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: BarrsRestoration]
#1494999
09/02/13 11:41 PM
09/02/13 11:41 PM
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Joined: Jul 2007
Posts: 11,836
Florida
mopar346
Let me tell ya about fat chicks!
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Let me tell ya about fat chicks!
Joined: Jul 2007
Posts: 11,836
Florida
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Great thread.
Is one (self etch or epoxy) more weather resistant than the other? For instance in the case of a drivign paint good or one that is kept outside while working on other parts or other cars?
Careful, your character's showing!
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: mopar346]
#1495000
09/02/13 11:54 PM
09/02/13 11:54 PM
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Joined: Sep 2004
Posts: 654
MN
astrobuf
mopar
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mopar
Joined: Sep 2004
Posts: 654
MN
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Leaving any primered car outside and exposed to the rain and the sun is a bad idea. Primers lack UV stabilizers and so will degrade when exposed to the sun. If you gotta leave it out, you at least should tarp it to keep the sun off, bu tyou also need to keep it dry from dew/condensation...
In general, I think the literature favors epoxy's ability to seal out moisture and oxygen over that of etching primers. Note as we've discussed above, that if you let the epoxy dwell more than a week, you'll need to scotchbrite it prior to applying the next coat.
Astrobuf
So, are you really a Rocket Scientist?
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Re: Prep for painting over epoxy primer? Sitting a while
[Re: astrobuf]
#1495001
09/03/13 11:55 AM
09/03/13 11:55 AM
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Joined: Jul 2007
Posts: 11,836
Florida
mopar346
Let me tell ya about fat chicks!
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Let me tell ya about fat chicks!
Joined: Jul 2007
Posts: 11,836
Florida
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Thank you, don't mean to hi-jack the thread. I sure we have all or at least most of us have driven cars that are in primer while we are working on it. I currently have been driving the crap out of my R/T. I primed it several years ago to stop any further decay and to get it mostly one color. At this point I figure when it comes time I will strip it and start over but figured if there was a better bet for the time being I might shut it one week end. At this point I'm not even sure what I shot it with. Maybe it's another thread topic but I enjoy the thought of a driving restoration/build like in the old days. Remember when you were in high school and built your first car. IT was fun back then, no numbers to worry about.
Careful, your character's showing!
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