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Removing rust from stainless


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I’m looking at a 10 year old J Boat. Overall, the boat looks to be in pretty good condition, but much of the stainless stanchions have rust spots on them down toward the base. It looks as if there’s impurities in the stainless steel leaching out. Is there a way to remove or polish this out without replacing the stanchions?

As always, any sage advice is greatly appreciated. 

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If you can remove the lifelines and stanchions from the boat there is nothing quite like polishing with compound and a wheel. Far better, shinier and longer lasting than the hand methods done in-place. It will not be impurities in the steel. Scratches and small pits can be ground out with a flapper wheel. Larger defects are easily welded up to be undetectable. Bends more that very slight are the only thing which cannot be repaired.

After any polishing the surface should be passivated. The easy way is to wash well in fresh water and store in a warm, damp but NOT SALTY place for a week. The harder way is 25% strong nitric acid for a few hours. I heard soaking in hydrogen peroxide (from hair dressers) works too. Fancy welding or metal shops might do all this work.

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For chromed parts, believe it or not WD-40 and aluminum foil is the shockingly effective - spray part with the WD-40 and rub with aluminum foil - try it and thank me later :)

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Once the heavy rust is removed, coat with Collonite Metal Wax.  Really great stuff, and removes light rust very nicely without damaging the passivated layer.  Their insulator wax is particularly effective at keeping rust away, especially when used after metal wax.

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5 hours ago, ScowVegas said:

For chromed parts, believe it or not WD-40 and aluminum foil is the shockingly effective - spray part with the WD-40 and rub with aluminum foil - try it and thank me later :)

This.  It works.

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7 hours ago, European Bloke said:

Big talk. BF can do anything, it is the king. What is this product of which you speak?

image.jpeg.dbebc16c8092051afe4d1fde292e57f1.jpegWe've used both - this is better.

It's made by Lagostina to keep their S/S & copper pots & pans looking pretty.

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Nevr-Dull is a waste of time IME.

Doesn't even do a decent job on household copper & silver and that's a hell of a lot less challenging than marine S/S.

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I like Flitz, the 3M Marine Metal polish, and Wenol, which I found in a bag of stuff I inherited from someone somewhere.

Flitz also works well as an acrylic polish, surprisingly.

Wadded newspaper and spit is better than Nevr-Dull.

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18 minutes ago, Max Rockatansky said:

BKfriend is oxalic acid

that will remove the rust but cause more later, polishing is long term answer

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4 minutes ago, Bristol-Cruiser said:

Cleaning is the easy part, passivating is key to keeping the rust off.

I would add that a smooth defect-free surface is also key. The rust pox develops quickly in the surface imperfections. A properly polished surface will remain free of rust for months or years. Plus any rust that forms will easily wipe off. Such polishing will not be accomplished by hand with sissy homemaker goop. I'm three years into my wheel polished stanchions and pulpits. Perfectly shiny with only wiping after washing the boat. Welding shops have the products: cotton wheel, compound, passivation chemicals. Don't do it on the boat...super messy work.

I don't think oxalic acid will passivate. Only good for removing rust. I think citric (good tip @silent bob) and nitric are the go-to acids. I understand that the chemical process is dissolving the iron on the surface leaving the chromium behind. Some acids will not produce the water soluble iron compounds that lead to success. For example muriatic acid will destroy the stainless with chloride compounds.

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I think you're kidding yourself if you think you can passivate S/S by wiping something on the part.

I've had it done by pro's and it's called Electro-polishing. It's somewhat akin to chrome plating in that the part is immersed in an acid bath (look out for that!) and an electric current passed through it.

Done that way it removes the free iron molecules from the surface to a depth of one thou or so, leaving pure nickle and/or chromium on the surface.

Wiping something on, even scrubbing ain't gonna do that.

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7 minutes ago, SloopJonB said:

I think you're kidding yourself if you think you can passivate S/S by wiping something on the part.

I've had it done by pro's and it's called Electro-polishing. It's somewhat akin to chrome plating in that the part is immersed in an acid bath (look out for that!) and an electric current passed through it.

Done that way it removes the free iron molecules from the surface to a depth of one thou or so, leaving pure nickle and/or chromium on the surface.

Wiping something on, even scrubbing ain't gonna do that.

Well you are right about just wiping with clearer does not passivate. passivation is not done with electricity. the electro polishing is but is not like chrome plating . Electro polishing is a process that is used to remove metal ( not add metal ) from the part and by removing the metal smoothes the surface so to the eye the surface looks more polished. it removes the microscopic burrs left from mechanical polishing. Passivation is a separate process that can be done with or without electropolishing.    Passivation is done after electropolishing and is the process that removes the iron molecules from the surface of the part to prevent the stainless from showing rust on the surface. passivation does not use electricity, it is simply putting the part in a combination of acids and then rinsing it with water.

Spotless stainless does clean and passivate in one step and is very easy to use product. and it works and does not require any hand polishing 

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1 hour ago, SloopJonB said:

 

Wiping something on, even scrubbing ain't gonna do that.

There are acids specifically for this and yes they do work, spent many years in huge food production plant full of welded SS and tons of seawater.  Someone above mentioned the sailboat issue, it gets on other stuff, gelcoat etc and messes it up.  Alot of the marina guys use some sort of acid then hit with colonite and polish. Varying degrees of good or bad.  The old school production plant equipment polish after acid wash was kerosene and pig fat brick, super messy but gave a matte finish that lasts forever.

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2 hours ago, SASSAFRASS said:

There are acids specifically for this and yes they do work, spent many years in huge food production plant full of welded SS and tons of seawater.  Someone above mentioned the sailboat issue, it gets on other stuff, gelcoat etc and messes it up.  Alot of the marina guys use some sort of acid then hit with colonite and polish. Varying degrees of good or bad.  The old school production plant equipment polish after acid wash was kerosene and pig fat brick, super messy but gave a matte finish that lasts forever.

I think you are talking Collinite. Colonite sounds kinda shitty.

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3 hours ago, Overbored said:

the electro polishing is but is not like chrome plating . Electro polishing is a process that is used to remove metal ( not add metal ) from the part and by removing the metal smoothes the surface so to the eye the surface looks more polished.

Hence the "somewhat akin to..." comment.

If you reverse the polarity in a chrome tank you will also remove metal.

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1 hour ago, Israel Hands said:

What about rust spots on aluminum rail?  Mine is showing a couple of rust spots at stanchion bases. Bartenders Friend powder for that?

Anodized? Probably just wipe it...non-abrasive. Bare? Scrub away.

Aluminum does not rust. Usual culprit is a nearby angle grinder.

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3 hours ago, Israel Hands said:

What about rust spots on aluminum rail?  Mine is showing a couple of rust spots at stanchion bases. Bartenders Friend powder for that?

If it's not anodized, use this.

images?q=tbn:ANd9GcRJVpn_r0bMV6KyggSxXMs

Best metal polish I've ever used.

Buy the can - pricey but it lasts for years.

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On 4/17/2021 at 10:54 AM, Borracho said:

I don't think oxalic acid will passivate. Only good for removing rust. I think citric (good tip @silent bob) and nitric are the go-to acids.

Wanted to add that the go to stuff our oceanographic lab equipment people used for the stainless equipment they made to deploy at sea was Ospho (Fozz is another brand of similar content).  Basically, a mix of phosphoric acid and dichromate, with a few other goodies.  Great stuff if you can soak whatever you want to treat in it. Less useful of applied to the surface with a cloth or something.  Takes time (I usually give it a few days if the corrosion isn't bad), but will leave you with a fully cleaned passivate surface.

I saw the techs once broke a 1/4"tap off in a hole in part of a housing they had been building for an offshore sensor array, then tossed it in a vat of Ospho.  It took a good while (I seem to recall three or four months), but eventually it dissolved the entire tap, leaving the stainless housing in perfect condition for reuse.  They may have had to complete the tapping of the hole first. :)

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On 4/15/2021 at 4:51 PM, ScowVegas said:

For chromed parts, believe it or not WD-40 and aluminum foil is the shockingly effective - spray part with the WD-40 and rub with aluminum foil - try it and thank me later :)

so the wd-40 is to clean the rust and aluminum foil is just an abrasive to scrape the rust off...

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Ugh. I found that my sinks developed some small pits during the winter. For the life of me I don't remember leaving standing water in them. I used a bit of Bon Ami on a damp cloth thinking it would take them out, but no such luck. Should I move up to Bartender's Friend and maybe a scouring pad?

image.png.84101e0c975d060df7171baf0983e22d.png

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Bon Ami is too soft to touch stainless. Barkeeper's friend has more aggressive abrasives and oxalic acid to deal specifically with the rust. Keep in mind that it'll likely soften the finish so plan on scrubbing the whole sink to even it out.

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This stuff works amazingly well. Very little elbow grease required and you sink will look better the following day, honest. The active ingredient must keep working after it has been polished off the surface. 
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