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Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Electrolytic cleaning of aluminium

Q. I am setting-up a small business repairing motorcycle magnetos and would like to use electrolytic cleaning for the aluminium bodies (I knew a guy who used the process years ago, but he wouldn't tell me about it). Can anyone point me in the right direction, please? I believe the process he used turned the aluminium black by oxidising the surface and this blacking was then removed by some sort of reversal of the process? Trouble is I don't know what solutions are required.

Dave Fisher
- Northampton, England
2003

A. Electrolytic cleaning solution for aluminum:

potassium carbonate 100 gm
'water glass' ⇦ this on eBay or Amazon [affil links] 8 gm
1 lit. water, object=cathode (-),stainless steel anode (+),12 V,1-5 A/dm2, 10 - 30 sec.

Goran Budija
- Cerovski vrh Croatia
2003

Q. Hi,

what do you mean by "Water glass 8 gm" ?

Daniel Oliveira
- Algarve, Portugal
April 19, 2011

Sodium Silicate

on Amazon

(affil links)

January 6, 2013

A. Hi Daniel. ⇦ this on eBay or Amazon [affil links] . More detail on letter 15596.

Regards,

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

Q. The answer specified a Potassium Carbonate and Sodium Silicate electrolyte. I have used Calcium Carbonate for electrolytic de-rusting of iron and steel.

Is there a chemical reason to use Potassium Carbonate instead of Calcium Carbonate?

Paul Sperbeck
- Waukesha Wisconsin USA
August 4, 2016

August 2016

Potassium carbonate
Sodium carbonate
Calcium carbonate

A. Hi Paul.
In general, potassium is much more soluble than sodium which is much more soluble than calcium.

Regards,

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

A. Hi Paul
Calcium carbonate is a naturally occurring mineral. It is found as limestone, chalk, marble, etc.
Entire mountain ranges are made of this and they have withstood many thousand years of rain.
It is very close to being completely insoluble so it is not a very promising basis for an electrolytic cleaner.

Geoff Smith
Hampshire, England
August 7, 2016

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