[ARC5] Cleaning and "polishing" aluminum...

Tue, 25 Jun 2002 21:16:03 -0700

Hello,

Please be careful about using steel wool on any aluminum parts. I have
learned the hard way that when you use steel wool it will leave tiny
particles of the wool in the pores and pits of the aluminum. Over time
(a shorter amount of time than you might think) the steel will react
with the aluminum. The particles will act like anodes and will cause
dissimilar metal corrosion. 

I tested this on the skin of a Beechcraft AT-11 and I was amazed just
how fast the pitting showed up.

We use 3M Scotchbrite products for aircraft work. The plastic media
doesn't leave anything behind to hurt the metal. Scotchbrite comes in
many different forms and abrasive strengths. The one I prefer to use are
the Roloc wheels. You can purchase a starter kit that has a range of
discs and mandrels. You can put the mandrel into any electric or
pneumatic rotary tool that has a 1/4 inch chuck. 

The problem that I see with cleaning a cover of a 274N radio would be
the final finish. To get the pits clean you usually need to remove a
fair amount of metal. The problem is how to restore a factory finish.
The radio wasn't polished at the factory but that is what you are going
to have to do to remove the swirl and abrasive marks left from the
mechanical cleaning process. 

There are Phosphorus based cleaning and etching solutions that will kill
the corrosion and generally brighten the surface but they don't remove
the pits they just clean them.

I probably created more questions than I answered. I just wanted to warn
everyone about the use of steel wool. In the long run it will do more
harm than good.

Good luck

Taigh Ramey

VINTAGE AIRCRAFT
7432 C.E. Dixon Street
Stockton, California 95206
209 982 0273 Hangar
209 982 4832 Fax
www.twinbeech.com
KEEP 'EM FLYING...FOR HISTORY

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Kenneth G. Gordon
Sent: Tuesday, June 25, 2002 8:29 PM
To: [email protected]
Cc: [email protected]
Subject: [ARC5] Cleaning and "polishing" aluminum...

I want to clean up some really dirty BC-454/455 receivers, the all 
aluminum ones. Very fine steel-wool and lots of elbow grease do a 
good job, but I am getting really short in the elbow grease 
department what with my Rheumatoid Arthritis and all.

Is there some easier, better way to accomplish the same thing? 
Buffing wheel and compound or some such? I tried using a cotton 
buffing wheel and rouge, but that didn't cut the surface oxidation.

Suggestions from the collective wisdom gladly accepted...and 
acted upon.

Ken Gordon W7EKB
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Taigh Ramey

VINTAGE AIRCRAFT
7432 C.E. Dixon Street
Stockton, California 95206
209 982 0273 Hangar
209 982 4832 Fax
www.twinbeech.com
KEEP 'EM FLYING...FOR HISTORY

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