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jr438234606 07-30-2007 10:51 PM

My stainless sucks.
I own an asian-built boat with stainless of dubious quality. I find it impossible to keep the stainless steel rust-free, even in brackish environments. All of the winches, turnbuckles, cleats, etc, form surface rust quite easily. The rust will wipe off, and the part will polish up quite nicely again-- but this is becoming bothersome. In a salt-water environment, forget about it... everything rusts over the first day.

I have tried repassivating and polishing the parts. I've tried every paste, wax, acid bath, cleaner, polish, etc. to improve the situation. This has worked to some degree. I have some other non-original parts on the boat that don't form ANY rust under ANY conditions.

My question is this: Is there a way to have these problem parts plated with some metallic coating? Does anyone know of a company that does this? I would like to ship them the parts, have them "fix" the parts, and then return them to me.

RichH 07-30-2007 11:50 PM

Coating 304 and lesser grades of stainless isnt going to work as one single pinhole in the coating .... and you wont have any coating.

What you are going have to do is mirror polish the stainless (to about 5-10 micro inches), then get the parts electropolished. A mirror finish will retard the rusting. Any roughness, old weld scars, joints is where this 'stainless' is rusting - am I correct? If so your only alternative is to mirror-polish.

Mirror polishing is typically done with successively smaller and smaller grits of sand paper (down to 1000 grit) to remove ALL scratches and other surface roughness .... then power-buff on a high speed fabric wheel using 'tripoli' a mixture of clay and diatomaceous earth as the 'polishing rouge'. Usually just the mirror polishing is enough to prevent rust, but then you have to occasionally 'wax' the exposed surface to keep it from getting 'wetted'.

sailingdog 07-31-2007 12:00 AM

You could replace it with better quality stainless steel...

rewell6 07-31-2007 09:36 AM

The best thing to do would be to replace them as SD said.

Having them recoated isn't going to change the quality of the underlying metals. And if you went through all that trouble and the parts rusted again right away.... more frustration and wasted money

hellosailor 07-31-2007 11:54 AM

"I have tried repassivating" With some do-it-yourself product? Or sending it out for professional acid dipping?

The DIY products won't do the same job as acid dipping. But either one is just going to work on grains of iron left by tooling, etc. which are the usual cause of rust on stainless that has been worked with tool steel benders, etc.

If your rust is because of bad alloy, the only way to beat that is by replacing it.

RAGTIMEDON 07-31-2007 12:58 PM

IMHO it is not the tooling, it is not the polish. 304 stainless will rust in a salt water environment, regardless of polish. 316 stainless won't. The only way to prevent rust on 304 is to keep the salt water from coming in contact with the metal. This means coat it with wax, lacquer, or some other waterproof surface coating. Then the lines sliding over the winches will abrade the finish off! That means you can't use your winches again. OOPS!
At least the metal is not poisonous, like the pet food procucts, toys, etc we have been importing. When are Americans going to learn that cheap Chineese products are CHEAP! When you replace those winches, read the fine print. Metal parts used on salt water vessels should be made of 316 stainless. A chrome plated bronze winch is better, but a 316 stainless winch will be lower cost in the long run, but they aren't cheap!

sailingdog 07-31-2007 01:12 PM

Umm... the other problem is that 304 is far more likely to suffer chloride ion cracking and corrosion than 316 in a marine environment, and as such, should really not be used if possible.

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