After sandblasting...etching primer or epoxy primer [Archive] - Team Camaro Tech

: After sandblasting...etching primer or epoxy primer


bri-rock
May 22nd, 07, 06:31 PM
The shop that is going to sandblast my coupe only has etching primer to shoot the car with after the sandblasting. Is this okay or does it need to be the epoxy primer? If it does need to be epoxy primer, what brand and part# is recommended?

Gambitt
May 22nd, 07, 07:14 PM
I'd personally want epoxy...just go with a good brand like PPG or Dupont.

BA.
May 22nd, 07, 07:45 PM
etching primer is ok. It is just much less resistant to moisture, and not the better choice if you won't be painting the car for several months.

I vote for the epoxy if you can somehow swing it. I used DP90 by PPG. (it's black). They also make it in grey and I think another color or two.
I used black and sprayed it in my driveway. I've never even sprayed before!

rbanks40
May 22nd, 07, 07:55 PM
This is what I used, good price, quick shipment and great results.

http://www.autobodysupply.net/store/defaultin.asp?CategoryID=428

Miikeremains
May 22nd, 07, 09:16 PM
Doesn't need to be epoxy. Etching prime will do just fine.

sevt_chevelle
May 23rd, 07, 03:22 PM
Epoxy primer hands down!
At one time in the PPG tech sheets PPG clearly stated DO NOT use etch primer over sand blasted metal. Reasoning is because the etch primer can pool up in the pits and not evaporate out. Now you paint over that etch sealing over it. That non dry etch loose adhesion and starts to rust because the solvents are trapped.

Epoxy has far better corrosion protection and adhesion the etch. Plus sandblasted metal is the perfect tooth for epoxy.
Etch primer can be wiped clean off metal with lacquer thinner and urethane reducer, not so with a good epoxy...Eric

GMJoe
May 23rd, 07, 03:28 PM
epoxy here too, much better base to work off of especially if its a keeper....

Sid69Z's
May 23rd, 07, 06:03 PM
Here's a good discussion & explanation of why to use Epoxy instead of acid etch http://spi.forumup.org/about53-spi.html

As for the recommended brand, I use this and have had great results.
http://www.southernpolyurethanes.com/Product%20lines.htm

The only drawback is you will probably have to order it........but a big plus is the price is right!! :thumbsup:

CDJr
May 23rd, 07, 09:51 PM
Phooey on etch primer! Use epoxy :D

Good info, Buna-man Sid :thumbsup:

1yrat69
May 25th, 07, 09:04 PM
I have been in the restoration/collision business for 20 yrs and used PPG almost exclusively, The first thing you want to do is to make sure the metal is clean been for you spray anything on it. All the paint mfg will have cleaners to accomplish this PPG 330 is a good one for getting the oils from your hands and whatever has touched it prior to spraying, this is only good if done right away before surface rust has come in, if rust can been seen at all you will need to use some metal conditioner. Make sure you tack it off pretty good if you are not using lint free rags(paper) that lint will look pretty bad if you don't get it off. Etch primers are good for adhesion to clean bare metals because there is an acid in them, you definetely can't just spray etch on and leave it, rust will form! You definetely can not use an etch DPX171/172 under the DP line of sealers, However you can use PPG's wash primer which will go under the epoxy very nicely, but you don't really have to do this step with the wash primer (called that because of the viscosity very thin) just if you want to go the extra mile. DP is a very good product, but I would still put paint over it, DP is not chemical resistant, it is called a thermal plastic, (straight reducers will wipe it off, no matter how long it is allowed to dry) you want to put a paint or product that is called thermal set, (something that will dry and not be affected by any type of solvent) use a single stage black with a flattening agent to get a 20-30 degree gloss, Autocolor has a product that you can spray over etch and get the semi-gloss look that is durable looks great and is chem. resistant and it is very tough , it's called engine bay, I use paint code WA 8555 which is GM black, only draw back is that it is pricey, but you can get same results with a single stage paint with a flattening agent, Talk to your paint supplier they should be able to help you, hope this helps you, Shawn

bri-rock
May 26th, 07, 06:13 AM
Thanks everyone for the helpful information. :D

bdzee
May 27th, 07, 06:28 AM
I prefer to use a conversion coating first, then rinse, then epoxy prime over that once thoroughly dry. Never had rust come back. I still have some of the cars I use this system on and 15 years later they are rust free with no sign of rust coming through or back.