In an attempt to get a little differant look, a friend has
tried casting with quarters insted of sterling silver. You
know the sandwitch quarters. Problem: The castings have come
out of the investment with a dark finish. The finish is
difficult to remove, like fire scale. We are vacume casting.
Why aren’t the castings clean like with sterling?
I am sure the problem has something to do with the high copper
content or possibly other metals alloyed into the quarters.
Hi John… i would not recommend casting with quarters…I
don’t think they were "designed for the Process"you could
vibratory them for a while… that might help clean them up. I
don’t know what alloys are involved and thereby cannot really
offer any advice other than “don’t use them” white bronze from
Oster metals in Providence RI might be a better alternative if
you want something white .
The quarters are not silver, non what so ever. They are
stainless and copper.
John, I did a little numismatic research on the net and
came up with the following info from the coinworld online
site:
Up to 1964, U.S. quarters were 90% silver, 10% copper.
From 1965 to the present, except for the 1976 bicentennial
commemerative coins, the quarter is a laminate with the
core layer being pure copper, and the outside layer being
75% copper and 25% nickel. For '76, the proof sets and
uncirculated sets sold for collectors had outer layers of
80% silver and 20% copper, and a center core of 21.5%
silver and 78.5% copper. This source, unfortunatly,
doesn't say what the relative thicknesses of the core and
outer layers is, so we still don't know the alloy of a
melted down quarter. But it's probably fair to say it's
mostly copper, with a bit of nickel...