Surface Rust on Stainless Steel

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Windhover

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Our new, to us, boat is five years old and many of the stainless steel fittings are showing surprising amounts of surface rust stains. Since this is on a number of different fittings such as rigging screws, radar reflector mounts, chain plates and bowsprit which have come from a number of different suppliers, it would not seem to be an inherent material specification problem. Our rigger has suggested that it is most likely that the boat has been exposed at some time to a contaminant of some sort which has affected all these different fittings. His advice is to clean off the rust stains, and thoroughly clean all the affected fittings, and hopefully it will not recur.

Can anyone reccomend how best to clean rust stains off stainless steel? Any "magic" products, commercial or otherwise, or just a Scotch-Brite pad and lots of elbow grease? Any ideas welcome.

Thanks
 
If you leave a steel spanner on a plate of stainless, you will get a nice imprint of the spanner on the stainless. This has to be removed with pickling paste. Can someone explain why?
 
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Don't use scotchbrite - you'll scratch the mirror finish.
There are plenty of kitchen skooshers which will do it with a soft cloth, or try oxalic acid if it's really stubborn. (you will already have that in stock for brightening the waterline I assume)
 
I've found Lidl's stainless steel cleaner to be remarkably good. Cheap as chips too.
SWMBO wasn't happy when it went missing from the kitchen.
 
If the stains are really bad you could try pickling paste that stainless fabricators use for cleaning the welds. Be extremely careful as it is potent stuff and needs to be well washed off with plenty of water.
 
Ceramic tile grout cleaner which contains dilute Phosphoric acid.

Phosphoric acid is a rust converter.

Also removes rust stains from paint and gelcoat.
 
Windhover said:
Our new, to us, boat is five years old and many of the stainless steel fittings are showing surprising amounts of surface rust stains. Since this is on a number of different fittings such as rigging screws, radar reflector mounts, chain plates and bowsprit which have come from a number of different suppliers, it would not seem to be an inherent material specification problem. Our rigger has suggested that it is most likely that the boat has been exposed at some time to a contaminant of some sort which has affected all these different fittings. His advice is to clean off the rust stains, and thoroughly clean all the affected fittings, and hopefully it will not recur.

Can anyone reccomend how best to clean rust stains off stainless steel? Any "magic" products, commercial or otherwise, or just a Scotch-Brite pad and lots of elbow grease? Any ideas welcome.

Thanks
Click to expand...

Mainly because I had some tubes left over from my classic motorcycle shop I have been using Solvol Autosol. Works great,not too much effort but produces a deep shine. Be careful if you go this route not to step on the open tube-I always do!
 
ghostlymoron said:
If you leave a steel spanner on a plate of stainless, you will get a nice imprint of the spanner on the stainless. This has to be removed with etching liquid. Can someone explain why?
Click to expand...

My best guess is a combination of two effects. Galvanic corrosion will occur between the carbon steel (active)and stainless steel (noble) causing the spanner to rust, generating some staining. However, there could also be crevice corrosion between the two, which will affect the metal with the protective oxide film, i.e. the stainless steel.

A third possibility, which is maybe pushing hypothesis a little too far, is that galvanic corrosion might occur between the rust and the stainless steel, causing the latter to stain. I would assume that rust will conduct to some extent and that it will be more noble than stainless steel, but I have no data to back this up.
 
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