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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Copper plating was cleaned with bleach; can it be saved?
Q. So we have a copper plated incubator in our lab. I cleaned it yesterday with 10% bleach (yeah I know bad idea). I didn't notice any difference in the color at the time so I proceeded to sterilize the incubator by heating it to 90 °C for 25 hrs. When it was done the copper had this pinkish/red look to it. I know this isn't a chemistry website but I feel I probably oxidized the copper with the bleach (but if that is the case it should be green or black) so I'm confused by the color result. Bottom line is did I destroy the copper (meaning the copper plating was stripped) or is it still intact just in a different form and can still be used as an antimicrobial even though it aesthetically doesn't look the same. I feel the company will tell me I have to buy a whole new incubator just to try to make more money off of me. Thanks for any help you can offer.
Ben Hillbiologist - New York
March 25, 2009
A. Sounds like it oxidized and may need to be electrocleaned.
Shawn Michaels- Kingman, Arizona
A. It sounds like the copper is still there - the bleach may have removed some kind of lacquer or post plate surface treatment layer.
It's absurd to buy a whole new unit because of something like that. If esthetics are that much of a concern, you might try cleaning it really well, then applying some kind of cold blackening solution for copper and copper alloys to the surface. This would give it (well, one hopes) a pleasing aged, brown black look. Sadly, it's impossible to say in advance how such things will come out.
If you just leave it be, it may naturally tarnish in the air to a better look.
Next time, you might try disinfecting with some chemically milder biocide, like one based on a quaternary ammonium salt.
Dave Wichern
Consultant - The Bronx, New York
A. Try Cameo "Copper, Brass and Porcelain Cleaner" ⇦this on eBay or Amazon [affil links] There are similar products out there, but this product is very good at this application. It works great on the bottom of Revere Ware (copper bottom pans). A slightly abrasive pad (like 3M's Scotchbrite), water, maybe a little dish detergent, and a little elbow grease are all that is needed to 'finish' the project.
Tom Rochester
CTO - Jackson, Michigan, USA
Plating Systems & Technologies, Inc.
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