Why is rust forming??

[jr438234606]

Hi All,

I have two large vintage Cheoy Lee Stainless Steel winches on my boat that continuously rust over. I don't mean deep-pitted rust, the kind that is destroying the metal, but rather a surface rust that wipes off easily. I find myself constantly having to polishing the winches. Other newer winches I have on the boat don't do this. Is this an indication of poor-quality stainless steel? Could it have something to do with the age of the winches? Is there some coating or treatment that would prevent this?

john

[hellosailor]

John, it could be that the alloy rusts, some "stainless" does. Or it could be contaminated with iron, the result of someone polishing it with wire wheels or "steel wool" which embeds tiny splinters that rust. When stainless parts are machined or formed on carbon steel tools, they also get splinters in them that can rust.

The solution is to "passivate" the stainless, which is done by picking it in acid (traditionally strong acid...IIRC muriatic, sometimes citric acid now in an effort to mollify the EPA) to etch out the contaminants.

That requires taking the winches, or at least the parts that are rusting, off the boat and to a "plating" shop that does chrome plating and/or anodizing, and asking them to process the parts for you. Passivating may or may not solve the problem, if the alloy itself is part of the problem you would also need to have those parts rechromed, or replated with something else to seal them. If you check your yellow pages for some plating shops, ask about dropping in and showing them the problem, they may be able to recognize it on sight.

The bas news is...money. The good news is...you'll have real pretty winches with a new durable finish on them and no more rust.

[capn_dave]

The type of stainless used? They might of used 304 type. All stainless will get aome rust. That is why it is called stain-less.

Most winch drums are not stainless they are chrome plated.

Fair Winds

Cap'n Dave

[hamiam]

Wichard makes a product called Wichinox that they claim restores some of the passiveness to the steel. Personally, Ive had good luck with this product and its worth a shot for $12 or whatever it costs.

[sailingdog]

IIRC the acid used to passivate stainless steel is phosphoric acid. There are several products on the market which will do a pretty good job of it.

[jr438234606]

Update: I tried the Wichinox product and I am VERY pleased with it. Where I would remove the rust and it would come back within a week, the Wichinox has kept it rust-free. It's also brighter-- it looks brand new and is staying that way. I had a hard time finding Wichinox at West Marine. It's not kept with the cleaners. They keep it with the sailboat hardware. Thanks for the advice.

[Muckabout]

Now this is what I think this board is all about, folks sharing their knowledge about ways to do things right/better. Thanks for the tip wish I had known about this product before.
Kay