Best way to clean stainless steel?

[Spissgatter W-9]

Apart from rouge and a buffing wheel which I can't use because of the way they are constructed, how would you recommend cleaning stanchion bases?
Thanks

[Bob Smalser]

Green rouge and stitched cotton wheel mounted on a portable angle grinder. Make a 8"x8" or so cardboard or doorskin shield to protect the surrounding deck.

[Canoeyawl]

I would advise caution when cleaning Stainless steel boat parts. Most marine SS parts are chemically Passivated when purchased and any aggressive cleaning or polishing will remove this coating thus opening the door for crevice corrosion and further surface contamination.
Stainless steel works because of a thin transparent layer of oxidation that forms a protective passive film protecting it from corrosion, if this is removed you are asking for trouble.
The best way to deal with unsightly stainless items is to clean and/or polish them and then have them re-passivated. The passivating itself is a cleaning and brightening process however (it’s essentially a nitric acid bath) and is not prohibitively expensive.

[Vincent Serio III]

I have a number of stainless parts that have corrosion that I need to clean and refurbish and I'd be interested in learning more about this. I looked at the following link, a NASA tech-brief, that describes using citric acid: http://www.nasatech.com/Briefs/july04/PSSP.html

Is this something we can do at home using citric acid, or is it best to "have somebody do it"? Who does this sort of thing? Machine shop? If citric acid will work, can you get that locally? etc etc.

[Jay Greer]

I have to agree with Canoeyawl on this one. The only, effective, process to clean stainless is to have it electro polished. That has been my own experience. For light cleaning when needed, we use a German polish in a tube called "Simichrompoli".
JG

[ssor]

Vince, Citric acid can be purchased at any store that sells home canning supplies. It is added to foods that have a low acid and are processed by the boiling water method.

[Mrleft8]

This is an extremely timely post for me.... Somehow, during Lawn Tractor Polo this year lots of burned food dross was left over night on my stainless steel range top. Carter decided to scub the hell out of it with "Bon Ami". 2 days later we had "rust" on the stove. Citric acid? diluted to....?

[ssor]

Left8, don't worry about the dilution . Citric acid comes as a crystalline powder. A tablespoonfull in a cup of water is probably enough. That concentration will desolve the shell on an egg.

[donald branscom]

Apart from rouge and a buffing wheel which I can't use because of the way they are constructed, how would you recommend cleaning stanchion bases?
Thanks

To clean the stainless steel apply phosphoric acid (West Marine metal prep $9.00 qt.) wirh a brush or sponge and leave it on for one hour then brush with a stainless steel tooth brush. Wash the entire area with fresh water. It will be clean and the corrosion will be in check.

It will look like new.

If you want to buff it. use a buffing pad on a electric drill with WHITE buffing compound.

By the way phosphoric acid is in every living thing, in lower concentrations of course. Just rinse with lots of water.

[donald branscom]

I would advise caution when cleaning Stainless steel boat parts. Most marine SS parts are chemically Passivated when purchased and any aggressive cleaning or polishing will remove this coating thus opening the door for crevice corrosion and further surface contamination.
Stainless steel works because of a thin transparent layer of oxidation that forms a protective passive film protecting it from corrosion, if this is removed you are asking for trouble.
The best way to deal with unsightly stainless items is to clean and/or polish them and then have them re-passivated. The passivating itself is a cleaning and brightening process however (it’s essentially a nitric acid bath) and is not prohibitively expensive.


Electropolishing or passivating is an etching process that actually removes a minute layer and then a lead paddle is passed around the part in the bath of chemicals to aid this process. Plating parts get charged for by the pound so the more you take the better deal you get because of the minimum rate. The process of passivating gets involved but you can look it up on the internet. Use white buffing compound not green. If you treat the part with phosphoric acid it will turn the iron oxide in the stainless to iron phosphate which is inert.The white is finer than the green. Most platers refer to passavating as Electropolishing. It really does make the parts look good and protects them. Any stainless rigging parts that are 10 years old are suspect for cracks. I know because I welded and worked with stainless for 11 years on a daily basis on new weldments as well as repairs and inspections.

[donald branscom]

I have a number of stainless parts that have corrosion that I need to clean and refurbish and I'd be interested in learning more about this. I looked at the following link, a NASA tech-brief, that describes using citric acid: http://www.nasatech.com/Briefs/july04/PSSP.html

Is this something we can do at home using citric acid, or is it best to "have somebody do it"? Who does this sort of thing? Machine shop? If citric acid will work, can you get that locally? etc etc.

Plating shops do Passivating, or as they call it - Electropolishing.
The citric acid treatment is being experimented with by the military.
However it is used in conjuntion with an electrical current and other acid combos. It is easier to get phosphoric acid (Ospho) which is used in passivating or electropolishing. The pros use about 25% sulpheric with phosphoric ,electrical current and ion heavy water to aid the electrical current. You can get West marine metal prep which is phosphoric acid. It works.

But before you spend a lot of money on the electropolishing make sure the part is worth it. Visually inspect the part with a magnifying glass. next level I would do is have a welder strike a TIG torch arc on the surface of the part and the welder will be able to see all the cracks in the part if any. Otherwise dye penetrant test. Or take the parts to a welding inspection lab and have them x-rayed. Remember there is stress corrossion and a 45 ft. boat can have 50,000lbs of load on a forestay fitting.

[Spissgatter W-9]

I've polished what is accessible with red then white rouge. What I can't get at with the buffing wheel is what is causing me consternation. I have some phosphoric acid that I used to treat/protect the iron keel before applying epoxy paint. I was unaware that it could also clean ss. Will give that a try. thanks gents.
geo

[donald branscom]

I've polished what is accessible with red then white rouge. What I can't get at with the buffing wheel is what is causing me consternation. I have some phosphoric acid that I used to treat/protect the iron keel before applying epoxy paint. I was unaware that it could also clean ss. Will give that a try. thanks gents.
geo

The buffing compounds from rough to fine:

Brown, Red, Green, White

[donald branscom]

This is an extremely timely post for me.... Somehow, during Lawn Tractor Polo this year lots of burned food dross was left over night on my stainless steel range top. Carter decided to scub the hell out of it with "Bon Ami". 2 days later we had "rust" on the stove. Citric acid? diluted to....?

If a steel brillo pad was used the corrsion will continue,
When steel is rubbed against stainless the corrosion begins.
Like when stainless is transported on a steel truck rack then slides off the steel rack. Thats why stainless tubing comes wrapped in a paper sleeve when coming from the supplier.

You can put the corrosion in check by treating with phosphoric acid.
I have seen brand new bathroom deviders made out of stainless ruined when maintenence personel tried to scrub off graffiti by using a scratcher pad of some sort.

[Kim Whitmyre]

Wichard sells a paste for re-passivating stainless steel in the field:

http://www.wichard-usa.com/Catalog/images/P27-7.gif

[Spissgatter W-9]

What would be the advantage of the paste over the phosphoric solution? Is it keeping it off of things one doesn't what "re-passivated"? The paste is much more expensive than the liquid based on a google.

[werner]

from the metals handbook : stainless steel cleaning and restoring corrosion resistance
5% dibasic ammonium citrate ; with 1% wetting agent at 82°c
(ofcourse pieces have to be degreased)

[John E Hardiman]

If a steel brillo pad was used the corrsion will continue,
When steel is rubbed against stainless the corrosion begins.
Like when stainless is transported on a steel truck rack then slides off the steel rack. Thats why stainless tubing comes wrapped in a paper sleeve when coming from the supplier.

You can put the corrosion in check by treating with phosphoric acid.
I have seen brand new bathroom deviders made out of stainless ruined when maintenence personel tried to scrub off graffiti by using a scratcher pad of some sort.

Don is correct here. SS is much softer than the steels used in abrasives/tooling. Those high carbon steel fines will embed in the SS and cause corrosion (i.e. the SS will appear to rust). Once this is done, the only way to stop the "rust" is to polish the fines out of the surface. Once saw a whole mess of SS threaded parts made scrap by using the wrong cutting tool.

[donald branscom]

What would be the advantage of the paste over the phosphoric solution? Is it keeping it off of things one doesn't what "re-passivated"? The paste is much more expensive than the liquid based on a google.

I have used the paste re-passivating product and it works very well.
Did not mention it because i did not remember the name. Thanks

[steelcrazy]

Stainless steel parts should be cleaned mildly. Look out for some gentle formulas that are perfect for light cleaning.


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[donald branscom]

What would be the advantage of the paste over the phosphoric solution? Is it keeping it off of things one doesn't what "re-passivated"? The paste is much more expensive than the liquid based on a google.

The paste or gel does do a good job but it is still not as good as taking the part to be electropolished.

[SV Papillon]

Probably the first thing you have to decide is if you are going to remove the pieces from the boat to clean them or not. If you are going to remove them then it would make sense to go all out and use a chemical cleaning and rebuff. If you are not going to remove them staying away from the harsher chemicals and going with a mechanical cleaning would make sense. For removed pieces I have had good luck cleaning with scotch bright then soaking them in a diluted mix of water and pickling paste for welding, an acid not sure which one, scrubbing with scotch bright in the mix helps too. It will remove any ferrous metal and stabilize the piece. After it has soaked for a hour or two, starting with fine scotch bright then working up through the buffing compounds. One caution to consider is if they are cast pieces using chemicals or bead blasting may turn up imperfections pitting and the like that were lurking underneath.

Jake