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Recipe to electropolish stainless at home

Years ago while working at Knolls Atomic Power Lab, we used to make retirement gifts that included little men made from stainless bolts. Once welded together we would put them in a solution (acid I believe) that was contained in a glass beaker. The beaker had a stainless plate submerged in the bath that was connected to one end of a battery charger ⇦this on eBay or Amazon [affil links] . The other end of the charger would be connected to the piece to be cleaned/polished. A few minutes in this bath and the little figures would come out looking as if they has been chrome plated. I never got the recipe for the bath and would now like to use the process to electropolish small stainless parts I make for my motorcycles. Is such a recipe available for home use provide proper precautions are used? I remember the beaker being under an exhaust hood at the time. Thanks.

Rob Sigond
Hobbyist - Albany, New York
2003

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People in the business tend to not use the word 'recipe', Rob, because the connotation of that word is that if you mix ingredients in the correct proportions success will usually follow :-)

And there is so much more to electropolishing than choosing an electrolyte (like excluding water, and operating in the 'polishing zone' rather than the 'etching zone'. Most of the common texts include not only several formulations, but a lot of additional info about what is involved. Please see the Metal Finishing Guidebook, Electroplating Engineering Handbook [on AbeBooks or eBay or Amazon affil links] , or ASM's Metals Handbook, Vol. 5.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

Ted, Thanks for the feedback. I'll check out the texts you mention. I was hoping that their might be a simple and foolproof formulation for home hobbyists that would also be relatively safe. Have a great holiday.

Rob Sigond
- Albany, NY USA
2003

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The one thing I can guarantee is that they are not quite safe for home use--having the ability to dissolve steel, nickel, and chrome :-)

They involve highly concentrated viscous acids, sometimes almost water-free. Sometimes straight sulfuric acid, sometimes with a mix of phosphoric acid, and several more. To get the solutions to dissolve the metal smoothly, without etching it and making it worse, is difficult and I am surprised your technician was able to make it look easy. If you do find the formulation and technique we would like to hear about it because I never knew anyone who found it easy. Thanks!

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

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2003

You can polish SS chemically:

25 gm oxalic acid ⇦this on eBay or Amazon [affil links]
40 gm H2O2(hydrogen peroxide)
o,1 gm H2SO4
1 lit water ,18 C, Min. 20 minutes

Goran Budija
- Zagreb,Croatia