Epoxy or self etching primer

[345 DeSoto]

Southern Polyurethanes. https://www.southernpolyurethanes.com/

[swvalcon]

Wittsend At work one day I had some 3-m adhesive clearer on a rag using it and this fresh out of school body tech goes YOU KNOW ACCORDING TO CA. THAT CAUSES CANCER IN LABORATORY RATS. I just told him what do I care I'am not a laboratory rat.

[Hallabutt]

Gary if you read my question carefully, I think that you will see that this problem was present ten years after the 62 GT was built, and was probably present on the 63, as well. I've probably owned 60-70 Studebakers during my 75 years, and these are the only two incidents that I have ever seen. I own 17 Studebakers today, some with their original paint, with little indication of the problem. So this is not an indictment of the company. The fact remains that it was an issue on these two cars, and I was wondering if other old timers had ever seen it. For multiple reasons, like storage, usage, and location, there would be only limited evidential information unless it was part of long term connection with the car. After only ten years and finding rust under shiny paint, is not 56 years.

[studegary]

Gary if you read my question carefully, I think that you will see that this problem was present ten years after the 62 GT was built, and was probably present on the 63, as well. I've probably owned 60-70 Studebakers during my 75 years, and these are the only two incidents that I have ever seen. I own 17 Studebakers today, some with their original paint, with little indication of the problem. So this is not an indictment of the company. The fact remains that it was an issue on these two cars, and I was wondering if other old timers had ever seen it. For multiple reasons, like storage, usage, and location, there would be only limited evidential evidence unless it was part of long term connection with the car. After only ten years and finding rust under shiny paint, is not 56 years.

I have owned more than 50 Studebakers in my more than 75 years. Most of what I said applies for 10 or 20 years, as well as 56. I did paint work on a lot of Studebakers that were not mine (at a restoration shop). I can think of rust on one car that was mine. When I stripped the roof on that 1953 Starliner, the metal was all covered with rust. I remember sanding and using a metal etch before starting a normal paint process. That was in 1972, so the car was 19 years old. My paint job on it (lacquer) held up for more than 30 years that I know of.

[(S)]

Old paints 'breathe'. If not waxed they will rust under the paint. It is just age and climate and the lack primers back then that did not 'seal' the metal from the air...

We have an old truck that was left out to rust and about 15 years ago, I attacked it with grinders, wire wheels, and spot sandblasted it. Some pits in the metal remained, some of the rust just would not come off. I then shot metal etch primer and the last 'real lead' epoxy primer on it. It has sat years pretty much rust free except where scratched, nicked.

That was PPG 1791 etch primer, and real DP epoxy primer with 401 and the stuff is the best I have ever seen. I have not 'tested' the new stuff in a while. I know that the DP epoxy primer would have never lasted that long by itself. The truck is still sitting outside waiting for paint. It will require 'touch up' in the spots that did not last and I hope the 'new stuff' is half as good.

[bezhawk]

Lacquer primer is not waterproof. Bondo is not water proof. If you prime in lacquer and it sits unprotected, it WILL rust under the primer.

[Hallabutt]

Thank's Gary and Mike for responding.

As I'm sitting here trying to process the additional pieces of data that you two introduced. Gary, you wrote about the top of the 53 rusting, I'm assuming the rest of the car was not rusty, is this correct? It seems to me that all horizontal surfaces would have been rusty unless there had been some rust present on the top prior to painting, and that wasn't present on the hood, trunk and other body surfaces. Otherwise all surfaces should have rusted uniformly, right? My guess that the 53 was two toned so the paint would have been applied in two separate processes, so maybe moisture introduced during short term storage, or paint was thinly applied. It's good to hear that you were able to forestall the rust problems, and it had lasted so well. This kind of comports with my own experiences.

Mike you wrote about arkyd enamel breathing. I admit that's a new one on me, but I never really gave it much thought, either. I know that the painting process at Studebaker was rather hit and miss. Since oxygen and moisture are necessary for rusting to occur, and since some cars that I've seen have vary thinly applied paint, from the factory, I can see why something like breathing might occur. I'll have to think about that a bit more.

Of my original cars, the 54's and 55's seemed to have held up better then some of the other years. The paint seems to be more heavily applied and more uniform. Then I began to think back, and came to realize that virtually all of them were Vernon produced. There is a much more forgiving environment in southern California, then in South Bend. Then there was the fact that parts when produced were sprayed with this thin layer of black primer. This stuff was then top-coated with little extra prep work. That primer will defiantly accept moisture, so during any moderate storage time the rusting process could begin prior to the top coating. Could the changeable environment be part of the problem?

I'd like to add that Studebaker's quality seems on a par with most American production cars. One real exception was the first water based pints that were use on GM cars in the 70's, but of course no Studebakers were being built during that decade. That was a real mistake, and they knew it! I never much cared for their lacquer, either.

I apologize for getting off track, but every time I have to chase another rust spot on the 63 I get irritated, and begin to wonder why. Thank's for humoring me.

[Dwight FitzSimons]

I have learned the hard way (the way I learn most things) not to EVER paint over rust, unless with POR-15 or similar product. On the exterior sheet metal I have always removed all the rust, no matter how small, with a chemical rust remover. Metal Prep will remove very, very light rust, but any rust like the OP's "black spots" would require a heavier duty rust remover like Naval Jelly, or better yet, Rustoleum Rust Remover. Both are about the viscosity of 30W motor oil. The Rustoleum Rust Remover is quicker than Naval Jelly, but doesn't seem to leave a rust-preventative coating on the metal like Naval Jelly does.

BTW, sandblasting or glass-bead blasting will make the steel look like there is no rust left, but it WILL still be there at the microscopic level. And it WILL come back. It will come back because all paints are porous (except POR-15 and the like).
-Dwight FitzSimons

[studegary]

I knew that '53 since it was new and I bought it from the original owner. The top did not appear good to me, that is why I stripped it and found the layer of rust. The only other original panels that I left on the car were the hood, trunk and one door. I did not strip them, but small repairs made on those panels showed no signs of rust under the paint. The top was Olympic Gray (I changed it to Shasta White.). The body was Tahoe Green. The car was a South Bend car that lived in NY and has now retired further south.