I'm in the bodywork stage on my coupe. This project is going on 5 years now. I have jumped around a lot and to prevent rust I have used various products. I have used metal prep from Home Depot. I have used rustoleum green etching primer in a spray can, and I have used permatex rust converter in a spray can, the type that turns metal black. I plan to sand most of this off and clean the best I can, but in places it is pitted and short of blasting I'm not going to get every little speck out of the corners and pits. I'm using kustom shop DTM epoxy primer sealer. I talked direct to TPC global and they say I shouldn't have a problem and to put the first coat on real light and see what happens, let completely dry scuff and put another wet coat on? I have read if some problems with ppg epoxy over anything with phosporic acid. Anyone have any experience with a situation like this? I have read a lot and done a ton of searches and everyone has a opinion. I'd like to hear if anyone has real life experience with this particular situation/product? Am I going to have trouble?
Just a hobby painter, but I have used their primers over a variety of substrates. All epoxy primers I have ever used are pretty aggressive, especially when used in cool temps. I would do as they recommend after getting most of the old stuff off. After you scuff down any reactions, the follow on coats usually work fine for me.
never use epoxy over any type of etch primer. I personally won't use epoxy PERIOD. But then again I have to stand behind my work. It's this simple Etch primer = phosphoric acid. It actually etches into the metal and forms a chemical bond Epoxy primer = mechanical bond, it needs a rough surface to grip to. Ethc primer = break through while sanding and you have a nicely feathered edge that can't be messed with Epoxy primer = break though it while sanding and you get a rough edge that can be popped off of the panel with air pressure or fingernail FWIW I took a CJ-7 hood that was in bare metal and coated it with Spies Hecker Etch primer ONLY. It has now been outdoors for 8+ years. There is NO rust on it except for a couple spots where I physically scratched through it, and the rust has NOT spread beyond the scratch. Meaning it is NOT penetrating under the surrounding areas. F epoxy
Fenders that's what I was hoping to hear. I'd really like to use it if possible. Scott so in this situation I'd like to use the epoxy since I have a gallon kit but I don't want any problems if I can help it. Would you just use a etch primer instead then? Are there going to be issues with a etch primer over the other stuff? I'm talking the areas around the cowl band and between the firewall and cowl. Places like that that are going to be hard to get to to strip. I do plan to strip all the junk off I can though. It is mostly stripped now. Is there something I can spray over these areas to block any possible reaction between the two chemicals?
Not all epoxies are the same. I use HOK KP-2 epoxy, pretty much exclusively, and never have a problem. AND it feathers out easily, even at a bare metal edge. I agree, though, that it has an aggressive solvent base, and will lift up any old, cheap, or inadequately applied paint or primer, It even lifts well done paint, if it is cool, or shot too wet. And HOK does not recommend painting it over an acid prepped metal surface. I think you really need to try to remove every spec of the old primers before continuing, or use a different primer.
Well any recommendations on what else to use for primer? Like I said I have it mostly stripped, and the acid washed off with water and scotchbrite then scotchbrited again with laquer thinner. The areas I'm worried about are inside And around the drip rails and around the cowl band and firewall area. There's no way every bit is coming out of every corner. Sandblasting is not an option at this point, I think blasting these areas will trap more sand to come out later than do good.
If you want to use the epoxy you have get a knotted wire brush for your angle grinder. That does a fairly good job of getting into areas like drip rails. As for etch primer over other stuff, I honestly couldn't tell you one way or the other. I've only had etch primer over top of bondo and top coat, incases where I had a spot that needed touch up and have never encounterd a problem with it in that situation. It might be time for you to mix up a small bit of the epoxy and put it right on one of the areas you are worried about and see what hapens. If it were me, I'd leave it on there for a week just to make certain nothing odd happens after it flashes off.
Well thanks for the input. I'm going to clean it all out and 8o grit everything and do a couple test areas and we'll see what happens. Ill report back how I make out.
Well thanks for the input. I'm going to clean it all out and 8o grit everything and do a couple test areas and we'll see what happens. Ill report back how I make out.
Opinions on PPG Epoxy over a light coat of rattle can Self Etching primer on freshly sandblasted steel? This is the green Dupli-Color NAPA stuff that has sat for over a year. Bob
Actually I am using kustom shop DTM epoxy primer/ sealer. Maybe I wasn't clear. I have heard of this problem with other brands such as ppg and wondered if there was the same issue with kustom shop stuff. Duplicolor,napa and sitting for a year? Not sure what your asking. Ill do some testing and we how it works.
I used southern polyurethane epoxy primer lays down nice, easy to spray priced well and free shipping I also plan on using their high build 2k and clear just my 2 cents
The Duplicolor has been applied to the blasted metal and sat for a year, just wondering if the PPG applied over it will cause a problem.
Well so far so good. I cleaned and masked everything and removed as much of the junk i could. i scrubed he areas that had metal prep on them with soap water and scotchbrite then rinsed with clean water. I did a couple test spots this morning. I didn't se any reactions so after another couple hours I went for it. It layed down nice and I don't believe I'm going to have any problem. Thanks for the input. I'll use custom shop products again.
Now I'm getting excited. Nice to see it one color. Still a long way to go though! Posted from the TJJ App for iPhone & iPad
I cant remember the last time I had a problem with PPG epoxy over anything. Its all in the preparation.
Epoxy primers should be applied to clean bare metal sanded with 80 grit, and applied sparingly over filler that you've applied to clean bare metal.
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