Bill Webber wrote: "I was admiring a nickel plated iron plane on the 'bay the
other day. It
was in generally nice condition and was advertised as not having been
cleaned and showed light rust in some places. My initial thought was
the rust would likely clean off pretty easily... Anyway, I'm thinking the
presence of rust on a nickel-ed plane indicates plating loss and rust of
the underlying iron...."
At times the rust will clean off too easily. The rust can work its way under
undamaged nickel and destroy the connection with the substrate, leaving the
plating weakly attached to the rust. A surface that looks almost solid plating
may have almost none of it adhered properly. I once picked up a plated center
punch in the street. It was badly nicked and battered from being run over by
cars, but it looked like almost all of the plating was still in place, with just
small spots of visible rust. After an our or two in citric acid, most of that
plating was at the bottom of the solution, and there was almost none left on the
punch. Each pinprick hole in the plating had caused rust under the plating the
size of a pin head, and there were so many that they joined up. Not the only
case I've encountered, but the most dramatic.
Tom Conroy
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