Metal finishing Q&As since 1989

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Removing chrome from tools

 

Looking for an easy way to strip the chrome plating from a socket or wrench. Also would like to know if there is an easy way of making a black zinc-oxide type coating.

Joe Skreczko

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You may know this, or may not, but the plating and metal finishing business is very jobshop oriented. There are shops listed in our Shops Directory, and perhaps in your yellow pages, that can handle this for you. In general it's not a D-I-Y project. While people call it "chrome", the finish is really a thin coating of chromium over a substantial layer of nickel, and--nickel being very similar to iron electrochemically--it's not at all easy to get the nickel off. Black oxiding is done in a boiling (285 °F) solution of caustic soda [affil links] (like Draino) plus nitrates, and it's just not a safe amateur project -- not only because of the aggressive attack on human skin by boiling hot lye, but the fact that water evaporates very quickly from it, and must be made good, so 'explosions' of the contents are not rare when water hits the 285 °F contents and flashes to steam.

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

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Stripping the chrome off is the easy part - common muriatic acid [affil links] will do the trick (although there will be waste disposal issues to deal with). The real trick will be to remove the nickel that was first plated under the chrome (almost all hand tools are nickel-chrome plated). My suggestion would be to contact a nickel plater in your area that also offers black oxide finishing to give you the black finish you are looking for and can do the stripping and waste disposal aspects of the job as well. Sorry, but this is more involved than most people realize in today's environmentally conscious society.

Dan Brewer