Probably almost a FAQ, but I was wondering since I have some money invested in one brand of epoxy primer and I have found the finish color I want to use with PPG ,, a different brand topcoat, if the PPG Acrylic enamel would work over the other companys Epoxy primers??? Actualy I would use the other guys epoxy primer , then fillers as needed, then a filler sealer paint from PPG and PPG from there out.

The paint store wiouldn't say one way or another as not to incriminate themselves.

Probably almost a FAQ, but I was wondering since I have some money invested in one brand of epoxy primer and I have found the finish color I want to use with PPG ,, a different brand topcoat, if the PPG Acrylic enamel would work over the other companys Epoxy primers??? Actualy I would use the other guys epoxy primer , then fillers as needed, then a filler sealer paint from PPG and PPG from there out.

The paint store wiouldn't say one way or another as not to incriminate themselves.

:no: Mixing paint lines is completely unpredictable, and even mixing within paint lines can be - for example, PPG DPLF epoxy primer can only be applied over specific PPG etching/wash primers. Compatability problems may not show up for some time - wouldn't it suck to have your finish start to bubble or flake a year after you paint?

IMHO, the risk isn't worth it. There's no one that can tell you with absolute certainty that a particular combo is OK.

My $.02

I say it is okay. Because you will sand the primer before putting on the sealer and basecoat this causes a mechanical adhesion. Where your sealer basecoat and clearcoat are working together as a chemical adhesion. I was told this by my instructor at school. It is okay (but not recommended by paint manufactures) if you primer with one brand and topcoat with another. After all that is what you are doing when you do a repair on a car you sand the area to create a mechanical bond and refinish on top of it.

Orange, I agree, not sure because I am not a painter, with your answer. I believe that the epoxy primer makes a chemical seal on the bare metal and acts as a base for further paints. I think any of the epoxy brands only give a short window before they have to be scuff sanded for any further top coats.

Still looking for advice though. Billa, I am not ignoring you answer either. I will spend a few more bucks to get there and I can prolly use the other brand stuff on another project so I am still up in the air on this subject.
I guess I am looking more so for a scientific answer rather than a paint manufacturers answer on the subject. I know that PPG also makes a " bondo like " filler but they sell about 3 other brands in the store they say will also work, so isn't this the same principal that should allow for what I propose to " chemicaly" work????
I remember doing a Jeep that a friend shot for me in Delstar base coat clear coat that I had started in an acrylic enamel, he talked me out of it and he painted over the top of my finish paint with DP-40 and went from there.

Yes you will be fine!

What do you think happens in the collision repair field on a daily basis?
A BWM that was sprayed with Spies Hecker paint from the factory gets into a fender bender. The repair shop repairs the fender and applies say Dupont over that existing Spies paint. No paint will peel off, or bubble up because its Dupont paint and not Spies.
Heck my personal truck has a hood that was repaired and painted twice.
Its got the facotry paint, then Sherwin Williams then PPG paint. The truck is a 94 Ranger and still looks brand new, no paint compatibility problems.

If you are appling your paint over a cured product it will not have a reaction with the underlaying product.

You get into trouble when you start using a product from PPG, lets just say a clear coat. Then you add a Dupont hardner to that PPG clear coat.
Thats when you get problems.

There are a couple of things here from my perspective and experience. I don't disagree that professional shops do this all the time - they know from their experience what works and what doesn't. I'm not a pro, but I've helped other guys paint and have painted myself and my observation is that that it's just not a certain thing. My experience hasn't been that "if you are applying your paint over a cured product it will not have a reaction with the underlying product" - I have seen this happen to a number of friends and once myself. There's a mechanical bond aspect, AND a chemical compatability aspect - read the datasheets. For example - and I tried this just to see - if you apply DPLF with -1 vs. -2 reducer on factory e-coat ("a cured product") it will start burping in a month or so. It's chemistry, dude :)

In the end, the decision comes down to (as I said up front) how much risk do you want to take? This stuff is EXPENSIVE and takes a ton of time, so I play it safe because a) I don't know, b) the paint data sheets say no, c) my paint shop, who will happily sell me anything says no and finally d) I can't afford to do it twice.

I read the same thing about applying over factory paint Billa. I will definetly pick up what the gal tells me for that process. I think I might just follow the " for sure" route anyway and save the extra stuff for another project.
If any of you are in the Medford Oregon area and can find Proffesional Automotive Finishes ( PPG store) check out the eye candy that they have working down there!!!!! Very nice!!!!
Good reason to switch brands as far as I can tell!!!!!!

Valdspar is the other brand I mention here.

using the same brand makes it easier and usually cheaper. The dupont Chromapremier line consists of etch primers, urethane sealers, urethane primers, basecoats, single stages, and clearcoats that ALL use the same hardener. saves $$$. nothing wrong with mixing brands as long as its the good stuff. its all the same anyway. like others said, just dont use PPG hardener with Dupong clear haha.