Bode,

        I have made copies of ancient Greek and Roman coins using a method
similar to what you describe.  To make the mold we used a two part
substance called RTV (Room Temperature Vulcanizing ) Silicone.  These
molds have a shelf life of approx. 25 years (depending on frequency
of use).  According to a conservator friend of mine, RTV is the least
harmful fo the Silicones and should prove relatively harmless to the
objects.  Since the molds last for a long time, the originals only
need to be in contact once.
        A real concern here is the fact that RTV will make scarely accurate
molds.  Some copies I have made have been mistaken for the real
thing.  While I am always quick to set the record straight, it is
prudent to control access to and use of these copies.
        Hope this helps.



Patricia McElyea
Curator of Collections
Arkansas State University Museum
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