Question for you guys. I have a 31 sedan body that I stripped and sprayed with a sealer a few years back. Making a dopey decision at the time, I didn't spray the inside of the car. Now I can see rust starting to come through at the two seams that are on the back of the car and along the drip rails. The plan is to completely seal the car (hopefully sooner than later) so that I don't have to worry about it, too much, while it lives outside under a quality cover. If I POR-15 the entire inside of the car, and possibly in the spots I see rust coming through the outside, before resealing and painting the outside, would that stop rust from growing? If not, I guess I'd have to break the seams and POR-15 in there too? Thanks in advance!
If the rust is in the seams between panels, the only way to address it is to disassemble them and address that area specifically.
As far as I know. Once rust forms in reality there is no way to stop it without replacing the metal, considering its a chemical reaction at a atomic level. But yes, severity and reforming is going to be dependent on a case by case basis. There are plenty of products and chemicals that can help with it. I would say the POR-15 if you use their three step process or something similar is your best bet. Anything that can eat away and seal what's already there will help. The best bet would be to take it apart and fully treat the area. But as long as it's a clean prepped area and seals can last quite a while. In the end you won't ever get rid of it but cutting off oxygen and moisture can generally guarantee longevity. Seams in general are terrible because they hold moisture and debris and are typically poorly covered or treated areas.
Corrosion mechanisms are a reaction of the material with its environment. Your statement about rust not being stopped is not correct. You can stop rust (iron oxide corrosion), but you can't reverse the damage done to the metal. Say if you have a pitted piece of metal, you can treat it and clean it up and stop the corrosion, but you can't make the pits disappear. What most people struggle with is they don't properly clean up or treat the rust, and that's why it returns. On cars that's usually not treating the areas where panels come into contact, such as folded over body panels and the areas between an inner and outer panel, etc.
My point was more once metal has been exposed to oxide corrosion. It loses the electrons around the atom. Once you lose the electrons, the atom is going to lose more electrons. Its easier to lose than it is to gain. Once thats happened the metal becomes weaker and more susceptible to corrosion as its going to want to continue to shed electrons. You are right, and I poorly worded my first statement.
It converts your oxide layer into a protective layer, correct? But the protective layer is on top of the metal layer. Since the process of oxidizing is removing the layers of metal and your just treating those layers. It doesn't actually do anything to add to or re-strengthen the metal, Right? It's essentially sealing the metal underneath. On the topic of acids though, isn't a tannic acid suppose to be better? I was thinking it provided more durable protection and didn't have to be sealed later like a phosphoric, I believe the two are whats usually mixed in your rust treatments? Anyway, correct me if i'm wrong. I'm just a young guy, it's always great to a have a conversation and learn something.
Need pics. What kind of rust. Is it separating the panels or just discoloring the seem? 99% of old car has rust in the seems. Ive repaired new cars with rust in seams.
Thanks for all the advice. I will take some pics. I was kind of hoping I could take the easy way out and it would still work. I figured if I could encapsulate the ENTIRE seam, then it would be ok.
This “rust bleed” was on a truck I bought once, apparently it was chemically stripped then painted. Rust bled through the seams. I sanded it down, used enamel primer on everything, truck was never garage kept, but 8/10 years later when I sold it, never had and bleed through the primer.
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