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HOLED COINS & PRE-SHRINK PREPARATION...
Posted by CAROLLEE on 12/7/2003, 6:30 pm I am interested in shrinking two 38mm coins [silver]. Each has a hole about 3/16" in diameter. Is that a problem ? Should I fill the holes with epoxy before sending them to you ? This should reduce the overshrinking in the area of the hole [?]. Please R.S.V.P., Thank you, Carollee 12/7/03
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Re: HOLED COINS & PRE-SHRINK PREPARATION...
Posted by Bert Hickman on 12/7/2003, 7:41 pm, in reply to "HOLED COINS & PRE-SHRINK PREPARATION..." Hello Carollee, As you are probably already aware, coin shrinking requires precise balancing of huge forces. Shrinking a coin that has a large hole located off the coin's center will cause the coin's shape to become quite distorted, with the coin's rim becoming indented in the area near the hole, as the forces try to fill the hole. If the hole was very small, it might work, but a 3/16" hole is relatively large. The closer the hole is to the edge, the greater the resulting distortion. If the hole is very near the edge, the thin section between the hole and the rim may melt or even vaporize from the heavy current flowing through the rim of the coin. If you filled the hole with a similar silver-copper alloy it might work. However, epoxy is quite brittle, is electrically non-conductive, and will likely not be strong enough to withstand the huge compressive forces. While I'm willing to try shrinking these coins for you, I can't guarantee that you'll be satisfied with the results. If possible, I'd really recommend shrinking similar coins first, then drilling the holes afterwards. Please send me a direct email at bert.hickman@aquila.net if you wish to proceed further. Thanks and best regards, -- Bert --
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