Protecting Stainless Steel

[scarlet]

I have been working on restoring the stainless steel hardware in our heads (hinges and handles on the shower doors... door handles.... etc. ) I'm removing them, grinding/sanding/polishing them to get the pitting and rust off. After all my hard work, I would like to protect them from pitting and rusting again. Any suggestion on what to use? should I just wax them? or can I apply a polyurethane on them to keep the moisture off? anyone have any suggestions?

[scarlet]

actually... the hardware may be chrome....

[Jim Cate]

Yep, probably chrome, and possibly over some potmetal stuff like Zamak (sp?), a proprietary alloy used by Perko (I think) and others, and not very good stuff at all. Even poor stainless should not pit in such applications as in the head.

So, if my guess is correct, I'm afraid that replacement is gonna be the only way to have them looking good for long.

Jim

PS If you post a good photo of an example we'd have a better chance of identifying the problem.

[Tracyandkimo]

I have a similar question. Let's assume it is stainless. What is the best practical method to protect it once it is cleaned or is new?
Thanks

[frozenhawaiian]

rub it with colinite insulator wax.

[ShoreFun]

Stainless is protected by various elements working together to prevent the iron from being exposed to oxygen. Welding, grinding, sanding all can expose the iron and cause some rust. In some cases where you have constant contact between water and the stainless you can get corrosion. Like where chain plates come through the deck. There are pictures of almost completely gone chain plates and all of it was hidden.
You have to use a chemical or electrochemical process to prevent the rust from forming after certain types of work on stainless.

I have limited experience in welding and working stainless so my above explanations are kind of general and may have some errors in them. You will need to research to find the exact details.

I have done some early car restorations, 1931 Ford. So I know a bit about plating.

Here is a simplified thing on plating.

Chrome plating is really a clear coat over the base color metal. It is an ultra thin coating that gives a blue tint to the base metal. So typically you have a nickel plate for the silver color, but nickel will tarnish. So the chrome plate prevents moisture and the blue tint makes the yellow tint of the nickel look brighter. Chrome is porous with tiny holes in it. That is why you see some pock marks. Here is where some types of wax help keep the holes filled and reduce that green stuff that seems to spring up over time.

Potmetals are great at first. The problem with plated pot metal is the pot metal will just start to oxidize. Once it starts it is not easy to fix. The part will need to be ground down past the oxide layer and then plated up. Part of the reason form pot metal was it did ok at making accurate castings with some strength. It was cheap and effective for manufacturing and lasted long enough. Of course, 20 years later the person trying to deal with it is not in a good place. Just imagine what it is like for the guy restoring a 1929 Ford that has an all pot metal wiper motor and all the pot metal is bad. The only option is to make it all new ($$$).

Corrosion in the steels is more about electric currents at a micro level. If you have something that can act like even a tiny electric circuit then you get a transport of ions. This is what causes corrosion. If you take a perfectly clean piece of steel and dropped pure water on it you would not get rust. Put a bit of something that makes the water conductive then you get rust. Salty dirty water like you find in areas with snow and salt and you find the cars are real bad quick where the metal panels overlap. They set up currents and you metal is done.

The only sure prevention is the never ending job of clean and polish.

[Pegu Club]

Originally Posted by frozenhawaiian

rub it with colinite insulator wax.

This ^^^^

Lasts for a fair period of time, but does require repeat applications from time to time. We use colinite on all exterior stainless.

Fair winds,

[Shrew]

stainless steel doesn't pit. It can rust, but that is typically as a result of a combination of water and lack of air. Some non-316 ss can form some light surface rust staining that can be removed with a brillo pad or metal cleaner.

If you're getting actually pitting, then it is either polished aluminum (unlikely) or chrome (very likely).