The E-Sylum:  Volume 8, Number 9, February 27, 2005, Article 9


Dick Johnson writes: "Galvanos are a necessary intermediate
step between an artist’s bas-relief model and the die to strike
a coin or medal. An artist prepares his oversize model in clay,
wax, plaster, wood, plastilene (a modeling compound) --
any media he is comfortable with. However, none of these
are sturdy enough as a pattern to place on the die-engraving
pantograph, commonly called a "reducing machine."

When the Contamin engraving machine was first used the
patterns were made of cast iron. Franklin Peale made a cast
iron pattern from Ferdinand Pettrich’s model of John Tyler
in 1842 to cut the dies – in three sizes – on the Philadelphia
Mint’s Contamin, it had acquired in 1836, to strike the Tyler
Presidential Medal. This was the first medal to be made by
this technology in America. (Actually Peale made a device
punch of Pettrich’s portrait relief of Tyler, not the complete
obverse die with lettering.)

The trouble with cast iron, however, is that it does not
reproduce fine detail. The relief is not sharp and crisp. All
edges of relief are rounded. Enter electroplating. Invented
in Germany, but developed in England, it was ideal for
making metal patterns to be reduced for diecutting in
addition to coating metal. This technology can reproduce
fine detail down to sub-molecular!

A galvano is an electrolytic cast. The artist’s model, which
now becomes the pattern, is coated with a metal powder as
a release agent. (Often this pattern is plaster like what I have
mentioned in the last two week’s issues of E-Sylum). The
metal powder covers the surface of the pattern and must
conduct electricity. The pattern is wired from this coated
surface to connect to a bar overhead.

This wired pattern is immersed in the electrolyte solution. A
direct current is turned on. It travels from a rectifier to bars
along side the tank to copper (or silver or gold) anodes in
the solution, through this to the surface of the pattern, up the
wires to the overhead bar, back to the rectifier to complete
the circuit.

The electric current carries away ions of metal from the
anodes (they wear away like a bar of soap) and deposit
on the surface of the pattern. The ions are microns thick
but deposit immediately and rapidly. It takes about three
day’s time, however, to build up, say an eighth of an inch
of deposited metal. The metal galvano is pried apart from
the pattern.

While galvanos are pure copper metal, with time they can
become brittle. Its molecular structure is such that it is not
like rolled or cast metal. Care must be taken in handling a
galvano. So here are my recommendations for handling
and storing a galvano:

1) Even though a galvano is metal, treat it like it was "moon
rock" – a very expensive object. Cushion it whenever you
can and carry it with caution.

2) After use in an electrolytic tank the galvano will still have
the copper wires attached to it. Do not remove these. In fact,
hang the galvano on racks by these wires. It is best if galvanos
do not touch the floor or touch each other. Let them hang
free. If the wires have been removed place the galvano in a
cloth shopping bag and hang by the handles of the bag.

3) Never, never lean a galvano against a wall or store in a
position where it is not supported. In time it will deform, it
will bend or warp and distort its relief image.

The demise of the galvano came after the 1960s when a
space-age material became available with somewhat desirable
characteristics – epoxy. Mint technicians found they could
mold an epoxy pattern from the artist’s model; after curing it
would be hard enough to be used on the die-engraving
pantograph, saving day’s of time in the galvano tanks. Most
mints use epoxy today.

In addition to being sturdy, galvanos are long lasting. Medallic
Art Company once made new dies from 65-year-old galvanos
-- Calverley Lincoln Medal of 1909 reissued in 1975 -- with
perfect definition of detail, no loss of original integrity. The
jury is still out if this could be done with an epoxy pattern.

The term galvano comes from the electrogalvanic process.
It was virtually unknown in the numismatic field. In his study
"A Numismatography of the Lincoln Head Cent," E.V.
Wallace in 1952 called it "Galvana" misspelling it and
capitalizing the term, it was so unfamiliar to him. Today
galvanos are represented in seasoned numismatists’
collections, as are plaster models (but I know of NO
epoxy pattern in any numismatic collection)."

  Wayne Homren, Editor

Google Web
The Numismatic Bibliomania Society is a non-profit organization 
promoting numismatic literature. See our web site at

To submit items for publication in The E-Sylum, write to the Editor 
at this address:

To subscribe go to:
Copyright © 2005 The Numismatic Bibliomania Society.



Copyright © 1998 - 2005 The Numismatic Bibliomania Society (NBS)
All Rights Reserved.

NBS Home Page
Contact the NBS webmaster