On plating parts, or re-plating parts if they are small and only a few
in number, you may want to think of doing it yourself.  You can get
small plating kits from a number of sources, at reasonable cost, for
simple copper plating of non-ferrous parts.

You use a hot pot with a solution of cooking alum or swimming pool
pH reducing chemical that has had some iron particles stirred in it.
This causes an excess of copper ions in solution so that the next item
placed in it will be copper plated.  This is good for copper plating
die-cast or white metal parts that go through another metal so you can
solder them together.

I will give a list of links to locations that have plating kits and
supplies along with a low cost booklet on plating.  This will give
anybody an overview of plating and using the equipment.

This guide explains it all using equipment to clean and plate:
  http://www.contenti.com/products/books/116-216.html
  http://www.contenti.com/products/plating.html

Has a number of different plating kits:
  http://www.micromark.com/   Look for plating on sidebar.

  http://www.eastwoodco.com/jump.jsp?itemID=407&itemType=CATEGORY

Plating and other coatings in spray cans.  Eastwood has a lot of stuff
that restorers of anything could find useful in the shop to keep the
costs down.

  http://www.ottofrei.com/store/home.php?cat=278  another supplier.

Most larger cities have a jewelry supply house; they generally have
the equipment and supplies to do plating, plus there are any number
of discussion forums on the web for plating.

Glen Perye