I have read people recommend "epoxy" and "self etching" primmer. What are their uses? My guess is the epoxy primmer is for painted surfaces and the self etching is for bare metal. Am I right or totally wrong? I am stripping a roof and I want to know what to prime it with. The car won't be painted for a long time. I need to prime the roof so it won't surface rust while I work on the rest of the body. Do I use a primmer/ sealer later?

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1969 Camaro 350 & 1969 Impala SS 427/ 4-speed (restored)

You are right but there is more. You can shoot epoxy over bare metal, it has good corrosion resistance properties, just not as good as etch. Many people use it that way and never use etch at all. I personally use both, an etch (wash) primer and an epoxy. That way you get the superior corrosion resistance of the etch and the "cush" of the epoxy.

On that roof....I would probably just epoxy prime it. It is the roof and not subjected to the same abuse as the rockers if you know what I mean. But, to etch inside of the drip rails wouldn't be a bad idea.



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Fan of anything that is interesting and moves human beings.
1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
1948 Chevy PU with 401 Buick

Thanks for the reply. What if you use metal prep on bare metal. Doesn't this etch the surface and eliminate the need for "self etching primmer"? Do you suggest self etching primmer then epoxy prime over that?

Yes, the "proper" metal treatment would replace etching primer in a way. And you NEVER want to do both. You have to have the correct products. There are metal "cleaners" and metal "conditioners." The Cleaner, does just that, cleans. It is a good thing to use before an etch or primer. The conditioner leaves an acid residue on the surface and that acid will attack the acid in the etch primer and you can actually LOOSE adheasion to the metal! The conditioner before epoxy is fine.

I personally like using an etch primer EVERY TIME. I use two different ones, depending on a few factors. If there is plastic filler, on the part, I use M-S Trio/PRIME, a thick bodied etch that gives a good film thickness. DuPont "Variprime" or PPG's DPX-171 are similar products, though not as much body. If it has no filler I use a "vinyl wash" etch by S-W under the NAPA Martin Senour label called "Vinyl Wash" clever huh? it is a very thin primer (you can see through it even) a similar product would be PPG's DPX-1791. The MS Vinyl wash gives even a better corrosion protection so I use it when I can. But it doesn't like plastic filler so I don't spray it when there is some. The etch primer is recommended under any primer or primer/sealer that I know of. It just gives added corrosion, period. Some argue that epoxy gives the same corrosion resistance because that is the way PPG has marketed it. But I have seen tests and epoxy gives much better corrosion resistance because of its sticky resins than urethane, but it is not as good as vinyl wash, PERIOD. The good thing about epoxy is it's versatility, it is the "bestest, fastest" way. It gives excellent corrosion resistance, good fill, AND, can be top coated without sanding! That is hard to beat, BUT, if you add the superior corrosion resistance of the etch primer (particularly Vinyl wash) you really have a good system.

The problem with epoxy is it sands like bubble gum. This is why I only use it in a non-sanding application like on chassis components or a rad support..things like that. Of course epoxy really kicks butt in painting semi trucks and things like that.

That is why I use urethane mostly. An etch primer then urethane (which really needs the etch, being it doesn't stick that well).

Then with the urethane primer sanded with 400 or 500 can be top coated without a sealer.



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Fan of anything that is interesting and moves human beings.
1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
1948 Chevy PU with 401 Buick

Thanks, thats just the detail I needed. Now the question of a novice. Is any of this available in a spray can. I have a gun and compressor but it is such a pain to setup and paint a small piece or section.

The etch can be found in a rattle can, but it is far from "real" etch.

The epoxies and urethanes in a rattle can.......It's coming VERY soon.

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Fan of anything that is interesting and moves human beings.
1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
1948 Chevy PU with 401 Buick

As far as painting small parts I got a Badger airbrush ( one of the 10$ deals) and was able to adapt a 4z bottle to it to spray the little things. Cuts down on the cleaning of that big ole gun, and saves on the lacquer to clean the gun with. Plus it lends itself to doing graphics too.
I shy away from the rattle cans of paint. Their not as good and I can't get the spray results that I want.
The epoxy primers are all I use after sanding down to bare metal.
Good to see you over here MARTIN Sr.

RandyB..