"patrick j" wrote in message
. com...
On Sun, 27 Mar 2005 16:00:38 +0100, nightjar wrote
(in message ):

Chromium is both harder and more chemical resistant than nickel. Its main
failing is that it is brittle, which means it will flake if used on a
base
that can flex. That, however, is a failure of the design, rather than of
the
plating.

Years ago I think I read somewhere that chrome is porous and so if used
alone
on steel/iron it will rust eventually. Nickel plating IIRC, is not porous
and
so can be used to protect steel/iron more successfully. The best thing
IIRC
for parts of cars/motorcycles being restored was to nickel plate and then
chrome plate on top of that.

Copper / nickel / chrome is the traditional system. Copper to adhere well
and to give a good base for the nickel, nickel to provide a flexible white
base and chrome to protect the nickel from discolouration. You can get
nickel plating solutions that adhere without the copper coat, but IME if you
want a really durable finish, you still have to have the copper undercoat,
even on brass.

....
Personally I've never had anything chrome plated but if I did want to
chrome
plate something I think I'd enquire with classic car/motorcycle
restoration
people because they do it a lot. There is very likely a newsgroup for
classic
vehicle restoration or something. Might be worth a try.

It is not too difficult to find platers who do chromium plating, although
the toxicity of the chemicals used, and the consequent problems of disposal,
means that the number is reducing.

Colin Bignell