Ask A Scientist© Chemistry Archive

name         Fred K.
status       educator
age          30s

Question -   My question concerns the restoration of old silver coins,which have
usually been buried (in the ground) for over a hundred years.
When the kids find these coins (with metal detectors), they sometimes
have developed pitting on the surfaces.
I am aware that professional coin surgeons use some kind of fine
dipped electroplating brush to fill the pits (in silver), and then
are fully blend the surface using various methods.
My question is: How exactly is the silveron silver- electroplating
done? Can this be an inexpensive project? >                                             ----------------------------------------
I do not have an answer personally, but I suggest you contact: 1. A
jeweler. 2. The curator of a local museum. 3. A local coin collecting club.
4. The Smithsonian Institute in Washington, D.C.

Hope one of these resources can answer your questions.

Vince Calder
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Fred K.,

The silver in silver electroplating as described in the
Plating and Metal Finishing Guidebook and Directory is
as follows:

Electrodeposition of silver from cyanide electrolytes
has changed little since first performed about 1840.
The use of soluble silver anodes, free potassium or
sodium cyanide to aid in anode corrosion, and the
presence of carbonate salts to aid conductivity has been
the standard approach.  Development of additives, grain
refiners and brighteners were the only form of evolution
in silver plating until 1970.  Several attempts have
been made to introduce non-cyanide systems, but to no
avail.

Sincerely,

Bob Trach
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