Epoxy primer or what?
 

I have been reading past posts for a while but this whole primer sealer paint thing is confusing. At this point I am interested in etching primer and epoxy primer. I have sand blasted metal on my cowl and firewall.
1 How do I properly prepare the sand blasted metal for the first layer of paint?
2 Should I apply etching primer or epoxy primer?
3 Can I put body filler over etching primer? What about body filler over epoxy primer?
4 Can I put etching primer over body filler? What about epoxy primer over body filler?
5 Is DP90LF a good product? I have read in these groups that some poeple don't like it anymore since the lead has been removed.
6 Are there any good websites that can help me understand todays current paint technologies?:confused:

Thanks for any help you can give.

Forget about the etching primer and spray the DP90 (or DP40, 50, 70) directly on the sandblasted metal. Also, you can apply filler over the DP90 and DP90 over filler. Heres a couple of sites/forums that may help http://autobodystore.com/forum/index.php
http://www.autobody101.com/

I'll attempt to answer some of your questions, based on my experience with PPG products..
1.,2., If it is FRESHLY blasted metal and you have a nice, dry air supply, go with the DP. If it has been days since the blasting, I would use PPG etching primer (reduced 10%), let it sit about a half an hour, lightly scotch brite over it and follow with two coats of DP. As a rule, where I work I always epoxy prime a complete body or part the same day it gets blasted or stripped. Even if it means I don't get out of there until 9 PM. (like Neil Young says, rust never sleeps)
3.,4., Never apply filler directly over etching primer, and never spray etching primer over body filler, any type of body filler. Apply filler on top of cured epoxy after scuffing the surface with something like 120 grit. Assuming it will air dry as opposed to baking, allow the epoxy a few days dry time before applying filler over it.
When the filler is ready for the first coat of primer, use epoxy again, two coats about 15 minutes apart. Wait at least an hour and then (without sanding) spray a couple of coats of a high build 2K urethane primer (PPG K-36) on top of the epoxy.
5. DPLF is a good product. It used to be better, but we can't do anything about that.
6. The websites above should help.


I'll PM you the website address for the shop where I work and you can see some pictures of the process I go through.

Thanks CDJr. I will check out those sites.
400 4spd thanks for answering those questions. Looks like you guys do great restoration work on your website. I want to do my car right this time. I repaired and painted it in 1987. I was 22 and didnt know a thing about restoration techniques. I rivited in patches, used fiberglass and bondo over rust holes. The internet has been a great tool to learn with. I often think how much smarter and more informed society is because we have the internet. I have learned so much on this site thanks to people like yourself, still questions lead to more questions.

1. If the metal has been sand blasted and I make the repairs to the area and its been over a week. I can spray the blasted area with PPG etching primer (reduced 10%), let it sit about a half an hour, lightly scotch brite over it and follow with two coats of DP. Then if need be after a few days of drying, I can put filler over the cured epoxy. Is this correct?

2. Just to be sure. There is no other step to do after I blast the metal and before I put on the epoxy. There is no need for a wash of some kind?

Thanks for your time guys.

You definitely DO want to "wash" the sandblasted metal before applying any type of primer.

My only experience is with the Sherwin Williams line of paint, but I am sure PPG has similar products. SW makes a "Met-L-Etch" solution that you mix up with distilled water, and spray on your bare metal. (part# W4K288) You let it dry on there and it forms a gray, chalky protective coating to nuetralize the flash rust and keep any more from forming. Then when you are ready to prime, you remove the chalky residue with a "Phospate Conversion" wash (part# W4K289).

The websites linked above also talk about using phosphoric acid solutions you can make yourself from pool chemicals you buy at home depot, basically doing the same thing I imagine.

Lastly, as a final step before applying any type paint, I would think you want to wipe everything down with a "wax and grease" remover type product to take off any glove marks, drops of sweat, etc. Like I said I am sure PPG has similar chemicals to work with their line of paints.

Good luck and TAKE YOUR TIME! :D

1. yes. The reason I reduce the etching primer slightly is because othetwise it will come out of the gun too dry and leave a fuzzy surface. And it only takes a light, even film of etching primer to do the job, not heavy coverage.
2. no. I use a metal etch if it is bare steel that was sanded (see the 71 GTX pics.), but on sand or bead blasted pieces I skip that. But, like I said, on those pieces I try and epoxy prime immediately.
I know that with PPG they caution do not treat the metal with acid if etching primer is to be used.
And always wear rubber gloves when handling bare steel. If you touch it, it needs to be treated with an acid solution to avoid adhesion problems down the road.