Rusty stain on the "Stainless" steel stanchion

[muskie]

Rusty stain on the \"Stainless\" steel stanchion

HI, is it possible to remove the rusty stain on the so-called "stainless" steel stanchion?
Thanks!

 

[Dipper]

Re: Rusty stain on the \"Stainless\" steel stanchion

Hull cleaners (the ones containing mild acid) work well.

 

[Talbot]

Re: Rusty stain on the \"Stainless\" steel stanchion

I use MER polish and this removes the rusty stain (unless it is really bad) and puts a coating to delay the on-set of more rust.

If it is bad, try brasso or some other metal cleaner (cause its more abrasive)

 

[Howardnp]

Re: Rusty stain on the \"Stainless\" steel stanchion

I use a scotchbrite pad and baby oil! By scotchbrite I mean the green (usually) pan cleaner thingy.

Rub the rust off with the pad then coat the area with the baby oil.

Works well, gets the rusty bits off and the baby oil coats it and stops it coming back...told to do this by a stainelss steel fabricator and initially thought he was winding me up but it works.

 

[peteandthira]

Re: Rusty stain on the \"Stainless\" steel stanchion

I was advised to use Solvol Autosol, but will try the baby oil thing!

 

[Lakesailor]

Re: Rusty stain on the \"Stainless\" steel stanchion

If you have commercial catering equipment baby oil is great for giving it a nice finish.

 

[cliff]

Re: Rusty stain on the \"Stainless\" steel stanchion

Unless you remove the cause of the "rust marks" you are wasting your time using baby oil etc as such treatments are only short term fixes and do not address the cause of the marks..

The ONLY way to get rid of the problem is to pickle and passivate the stainless steel. Oxalic acid will work if given long enough however the sure fire cure (to prevent the marks returning) is to use Stainless Steel pickling paste available from your local welding supply house or possibly from your local friendly/tame S/S fabricator if you only need a small quantity. The marks are usually due to iron contamination or carbide formation/precipitation (sensitising of the S/S).
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"Artificial intelligence is no match for natural stupidity"

 

[PCUK]

Re: Rusty stain on the \"Stainless\" steel stanchion

All stainless steel rusts if left unattended for long enough, . Regular polishing to maintain the oxygen film on the surface prevents rusting.

 

[cliff]

Re: Rusty stain on the \"Stainless\" steel stanchion

And where did you get this from?

Being a metallurgist I am really interested in your comments that "All stainless steel rusts if left unattended for long enough"

"Regular polishing to maintain the oxygen film on the surface prevents rusting." mmmm, - interesting theory but inaccurate. Regular cleaning will remove contamination from the surface but will do nothing to passivate the base material.
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"Artificial intelligence is no match for natural stupidity"

 

[seaesta]

Re: Rusty stain on the \"Stainless\" steel stanchion

In my experience 316 grade stainless does not rust whenever it is open to the elements. the only time you get rust is if you have unsuitable grade stainless or some part of the material is wet and in a confined area away from free oxygen.
My pulpit and pushpit have been open to the elements since 1966, they have not been polished or cleaned other than being pressure washed down at the start and end of the season for the past 20 years and they show no rust or other markings (other than seagull doo!)
Martin

 

[DeeGee]

Re: Rusty stain on the \"Stainless\" steel stanchion

[ QUOTE ]
The ONLY way to get rid of the problem is to pickle and passivate the stainless steel. Oxalic acid will work if given long enough however the sure fire cure (to prevent the marks returning) is to use Stainless Steel pickling paste available from your local welding supply house or possibly from your local friendly/tame S/S fabricator if you only need a small quantity. The marks are usually due to iron contamination or carbide formation/precipitation (sensitising of the S/S).

[/ QUOTE ]
Coming from a metallurgist, this is v interesting. I find most of the s/s (stanchions, selfsteering, turnbuckles.. ) gets this 'rusty' staining. I have always assumed it is cosmetic, and rubbed it off about once a year. Is it likely to have any other detrimental effect?

I seem to remember a whole thread about anaerobic corrosion, for example the wires into swaged-ends on rigging? Or the threads of the rigging turnbuckles? I seem to have lost that thread, any comment? /forums/images/graemlins/confused.gif

 

[cliff]

Re: Rusty stain on the \"Stainless\" steel stanchion

As it should be.
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"Artificial intelligence is no match for natural stupidity"

 

[Birdseye]

Re: Rusty stain on the \"Stainless\" steel stanchion

[ QUOTE ]
Unless you remove the cause of the "rust marks" you are wasting your time using baby oil etc as such treatments are only short term fixes and do not address the cause of the marks..

The ONLY way to get rid of the problem is to pickle and passivate the stainless steel. Oxalic acid will work if given long enough however the sure fire cure (to prevent the marks returning) is to use Stainless Steel pickling paste available from your local welding supply house or possibly from your local friendly/tame S/S fabricator if you only need a small quantity. The marks are usually due to iron contamination or carbide formation/precipitation (sensitising of the S/S).
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"Artificial intelligence is no match for natural stupidity"

[/ QUOTE ]

And does this prevent the staining on the (barely) type 302/304 stainless that is frequently used on boats? From the A2 nuts and bolts that are also often used? From underneath the deck mounting plates on stanchions etc? In which case why does anyone ever use 316 / A4?

Mind you I know what you mean about sensitising. I once made a deck plate from some hard rolled sheet that I had in stock, and attempted to soften it to allow drilling by heating with a blowlamp. I still struggled to drill, but ever after that plate rusted like mild steel

 

[PCUK]

Re: Rusty stain on the \"Stainless\" steel stanchion

Speaking from a totally practical point of view, it works!

 

[PCUK]

Re: Rusty stain on the \"Stainless\" steel stanchion

Moving on slightly, I once heard that rubbing garlic onto stainless steel acted as an effective drilling lubricant. Anyone else heard of this because each time I do any work with stainless steel I've never got a clove of garlic with me.

 

[cliff]

Re: Rusty stain on the \"Stainless\" steel stanchion

[ QUOTE ]
And does this prevent the staining on the (barely) type 302/304 stainless that is frequently used on boats? From the A2 nuts and bolts that are also often used? From underneath the deck mounting plates on stanchions etc? In which case why does anyone ever use 316 / A4?

Mind you I know what you mean about sensitising. I once made a deck plate from some hard rolled sheet that I had in stock, and attempted to soften it to allow drilling by heating with a blowlamp. I still struggled to drill, but ever after that plate rusted like mild steel

[/ QUOTE ]The majority of folk fitting their own deck fittings seem to buy their bolts from the likes of Screwfix, the quality of who's unbranded fastenings I have always found dubious. In addition do remember that in an effort to cut costs and maximise profits boat builders will source the cheapest components available and hence frequently source inferior products.

Back to your bolt question, during manufacture the bolts have to have the threads either machined (cut) or rolled. this involves using tool steel, or carbide, cutters, dies or rollers. This process alone can lead to a sufficient level of contamination of the S/S and unless this is removed by acid cleaning and passivating "rust" marks are inevitable over time. How many on here have stainless steel spanners and sockets? Damn few I am sure, and there is another source of contamination - use of CrV tools. Copper is another no-no especially in the presence of chlorides.

By all means clean and passivate your "A2" bolts prior to use and make sure all washers and backing plates etc. are treated in the same fashion. 304 S/S does benefit from pickling and passivation.

Had you treated the plate you tried to soften for drilling it would not have rusted like mild steel although by the sounds of it you used either 304 or 316 and not 304L or 315L and heated it into the sensitising range. If so you would need ot take it up even hotter to force the CrC to decompose and drive the C back into solid state Solution then quench to minimise the time spent traversing the sensitising range. Better to drill it cold though and pickle the holes afterwards to remove any contamination from the tool steel drill. That is if oyu wish to have a "stainless" component.
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"Artificial intelligence is no match for natural stupidity"

 

[cliff]

Re: Rusty stain on the \"Stainless\" steel stanchion

If you are happy cleaning every year then fine but i would suggest if you have a rusting problem "clean" them properly ONCE then forget about them apart from maybe a little wipe to get rid of airborne dirt.

See post above regarding treatment after machining.

When working with S/S cleanliness is above godliness if you wish to maintain the corrosion resistance.

Anaerobic corrosion is a different subject and occurs through different mechanisms to the "rust" stain phenomenon.
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"Artificial intelligence is no match for natural stupidity"

 

[DeeGee]

Re: Rusty stain on the \"Stainless\" steel stanchion

[ QUOTE ]
If you are happy cleaning every year then fine but i would suggest if you have a rusting problem "clean" them properly ONCE then forget about them apart from maybe a little wipe to get rid of airborne dirt.

See post above regarding treatment after machining.

When working with S/S cleanliness is above godliness if you wish to maintain the corrosion resistance.

Anaerobic corrosion is a different subject and occurs through different mechanisms to the "rust" stain phenomenon.
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"Artificial intelligence is no match for natural stupidity"

[/ QUOTE ]My searches, ages ago, on the subject led me to believe that ALL stainless steel will rust, but a passivated surface will rust very slowly, esp in salt water environment, I just assumed that the dirty rust stains (so unlike iron or mild steel rust) were such very slow rusting, and merely ensure that all gets washed with fresh water as often as possible. I should say that these stains are only v slight/light.

Now you make me wonder, and I must try this pickling paste, tho where I will get it in France is another matter. /forums/images/graemlins/confused.gif

Would still be interested in some info on the quite separate subject of anaerobic corrosion, even ref to the old thread which I cant find. /forums/images/graemlins/frown.gif

 

[robind]

Re: Rusty stain on the \"Stainless\" steel stanchion

Cheap oven cleaner from the pound shop. comes in a plastic "tin" like wax polish (astonish is the name, I think!) wipe it on leave for 5 minutes and clean offAalso great for getting rust stains off fibreglass.
Rob
PS keep it to yourself as we dont want everybody knowing

 

[starboard]

Re: Rusty stain on the \"Stainless\" steel stanchion

"Solvol Autosol" will not only remove rust from stainless but will leave a nice protective coating that will last all season. If it is really tough use a brillo first or even wire wool impregnated with the "Solvol" paste.

Paul.