Hello all. In reading most of the posts relating to primers it seems that epoxy primer is preferred over etch primer. Is there ever a certain condition that etch primer is preferred over epoxy? I had heard that etch, being more fluid can get into small cracks or other tiny openings better than epoxy. Is this true and is this the only place etch is preferred over epoxy? How about putting etch primer down first and then epoxy over it? My paint supply store had recommened epoxy primer on the frame and under body of the car, and etch primer on the rest of the car, followed by sandable primer. Thanks, Jerry

I used DP40 Epoxy on my 66 10 years ago and still no rust if this helps you any.

I alway vote for epoxy because epoxy are a 2 part mixture some just a 1 to 1 mix with etching you have to go to alot to get it right i use epoxy myself because the stuff is tuff & help prevent any rust but self etching i have heard is the best when it comes to protecting the metal.

I sprayed a friends top with the etch followed by DP40. I think if you get the metal surface prepped corrrectly, the epoxy should be fine. I have been just shooting the epoxy over the bare metal and leave it out in the rain. No rust yet.

I'm going to test a panel with a scratch of SPI epoxy and leave it out all winter.

I went with the DX1791 followed by DPLF and then K38. I put the etch primer on thin.

Etch primer is old technology. Epoxy is by far the way to go. If you spray etch into seems and enclosures you run the risk of the etch not drying properly and the acid can speed up rusting.

You can take etch primer and wipe it clean off metal with just a small amount of urethane reducer. How good is a product that you can wipe right off something?

Leave the etch primer on the shelves at the paint store, epoxy primer hands down...Eric

ok here goes i am stabbing at it. etch primer is only made to help promote adhesion. it is an adhesion promoter. it has some moister hold out. but you can also use it and a primer surfacer. i myself dont recomend that. EPOXY is like 98 percent moister hold out. it has excellent adhesion promotion capabillitys. they using both is moot. you have to etch then top coat, or you can simply just epoxy and sand seal and paint. no need for both. good luck.:thumbsup:

but you can also use it and a primer surfacer. i myself dont recomend that.

I have to highly disagree with that statement. PPG, Dupnt, S-W and many others have a MAX film thickness of around 1.0 mil. PPG states right in the tech sheet you need to remove excess etch primer if you exceed that film thickness. Anymore PPG claims lose of adhesive.

If da sand your metal with 80 grit and apply two coats of epoxy primer it will outlast any etch primer 10 fold...Eric

basf and diamont have DE 15 AND DE 40 which both can be used as precoat primer surfacers these are etching primers, and they also have ep25 26 27 are epoxy primers which are best on the market. by far.:thumbsup:

Correct me if am wrong but is the DE40 primer not a hyrid primer much like PPG's NCP primer? An epoxy/urethane based primer.
But none the less a true etch primer should not be used as a primer surfacer.
I will agree RM does make some darn good epoxy.

I am curious if the etch primer you guys are using is a two part catalyzed?? I know the old wash primers were not but the Standox I'm using is. I don't think you can wipe it off, but I'll give it a try.

There are self etching primer surfacers available but you might as well be using lacquer primer IMO as they are not a catalyzed product. I heard BASF and RM make some good epoxy primers but I've never had an opportunity to try them-no supplier in this area.

The absolute only time I use a self etching primer these days is for small parts with very fine detail where sanding and blasting for texture would not be an option. On the rare occasion when the part can't be textured properly for adhesion with epoxy then a self etch product is the only option. Epoxy needs texture.

the ep series is what we use. 25 26 27 these are the color which are white black and gray, these have etching primer built in. they are the best. we still use etching primer but we use it for spot repair or small parts and things. i am getting ready to paint my chevelle and it has to be right. and dead nuts perfect. born with motor LS6. after all metal work and filler is used i will epoxy only. if i bust through and hit metal when i block it. if they are just small spots i will etch them with a spray can, seal and paint. the epoxy primer is two birds one stone. good luck. :thumbsup: