Surface rust on stainless

[mike]

Give it a wipe over with oxalic acid, that will remove the staining. You could use Starbrite teak brightener, or their hull stain cleaner, the other alternative if availbe where you are is X10 which once again is a hull stain remover,, all the above ar oxalic based products.

Mike.

[boatpride]

oxalic acid is the active ingredient. You should use bristle brushes rather than the more aggressive carbon steel brushes and steel wool. These will scratch through the chromium oxide which protects the steel. Furthering the problem.

Cheers Chris
________

[warmrain]

[mitchk]

[warmrain]

[johnrobinson]

[mike]

[warmrain]

[mimoza]

Oxalic acid is pretty amazing stuff. It is an organic acid. Organic acids have a COOH group stuck onto some base molecule which defines the type of acid. Oxalic acid is just two of these COOH groups stuck back to back, so it is pretty strong for an organic acid. Still, like all organic acids it is considered to be a 'weak' acid by chemists. I know this is TMI for most of us, but here are the resulting properties and uses:

1) Oxalate really loves to combine with metals - good stain remover on many surfaces.
2) Makes kidney stones when there is too much calcium and oxalate in the diet.
(For a list of vegetables see http://www.nal.usda.gov/fnic/foodcomp/D ... xalic.html))
3) Unreacted oxalate will degrade rather easily, and there are no metals in it. It's OK for it to go into the sea.
4) Oxalate reacted with metals makes an insoluble precipitate (See 2). The only metal in the rinse-off is what was in the stain.
5) Removes stains from wood by removing metallic ions (See 1), and also lightly strips it, but only a thin surface layer.
6) Cleans heat exchangers. Most radiator flushes claiming to remove rust from your radiator are based on oxalic acid. I had a '46 Chev that stopped overheating after a good treatment. You have to wash it out right away to get all the junk out. (See 4)
7) Removes warts. [Not kidding. Wear gloves.]

With heat exchangers, one should be careful. Normally oxalic acid won't harm your exchanger, but if you have been remiss in keeping your coolant fresh, then deep corrosion might allow the oxalic acid to chew right through the walls of the exchanger. If this happens, then your exchanger's days were numbered anyway. For myself, I would not hesitate to use it on my heat exchanger if there were cooling problems; but after that I would keep a closer eye on the cooling system, and make sure the coolant is fresh. And, of course, don't forget the engine zinc.

HOOCCOOH - Good stuff.

[charles]

I had the same issue and found two commercial fixes: Barkeepers Friend and Zud. Zud works the best, but had to order online (East Coast product). It cleans the rust off very well (espicially paste). Still need to put a protectorent on after cleaning (found out the had way). I used the West Marine polish Brialliant (used to be Bright Boy). Hope this helps!

Charles
sv Seagate 38T
Chula Vista, CA