Electropolishing of Stainless Steel?

ferguson

ferguson

Joined
Feb 21, 2001
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Has anyone ever had a blade electropolished after mechanical polishing? I understand it's done extensively on marine hardware for corrosion resistance purposes. One source of info is http://www.electropolish.com/

Steve Ferguson
 
In the trade it is called passivation. It is usually done in citric acid to remove surface inclusions like mild steel that can begin corrosion by electrolytic action. If you are going to use a dissimilar metal for a guard you have defeated the purpose of the electropolishing.
 
George, please excuse my ignorance -- maybe dumbness. I don't understand why having a dissimilar metal for the guard defeats the purpose of electro polishing. Is this because you don't use the process until the knife is assembled, and the effects of the process will be quite different?

I'm thinking of just say a brass guard, with a SS blade. If the blade were electopolished before assembly, how would the brass affect the blade which has been processed?

Any help you can give my feeble mind would be appreciated.

Thanks,
 
There has been a big discussion on The Anvil about passivation of SS. If you have the electronic rust removal bucket, simply reverse the polarity to remove the surface iron (passivation of the steel).
I haven't tried it yet and wouldn't want to use it on 440C or anything like that.
Useless info, Lynn
 
Lynn is right useless info.

Passivation is done on stainless steel to prevent oxidation of the stainless steel due to electrolytic action caused by dissimilar metals embeded in the surface. Once the stainless is passified you can use it in wet enviroments with out worrying about surface oxidation caused by the dissimilar metals. Connect a dissimilar metal with a bolt and you have a battery and get electrolytic action, read galvanic action in some circles. One of the metals begins to corrode.

Don't sweat it, the brass usually goes first, the stainless dulls a bit too

Remember Stainless means just that STAINS LESS not stainproof.

I have done some electropolishing inside holes in a table salt and water electrolyte to brighten up holes that I could not polish, it is a slow process and gives a bright finish. Leave it too long and it eats the part away. Needs a lot of agitation to break up bubbles on the material surface.
 
Thanks, George. Appreciate it. Makes sense. I never thought of anything like a battery being formed. Had a lot of trouble with electricity in 9th Grade science. Been downhill ever since.
 
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