Quixote2
6th April 2010, 11:35 PM
The past few months have read many stories about the possibility of tungsten cored gold bars. People have said that copper or lead cored silver is easily detected by the difference in density. Copper 8.96, silver 10.49, and lead 11.34 grams/cc. Examples of copper cored coins were shown on GoldisMoney.info in the past.
I did some research into alloys that might come closer to the silver density of 10.49 g/cc.
I found data on various copper-tungsten alloys (used in electrical applications) and plotted the data in an excel spreadsheet. It appears that approximately 75% copper-25% tungsten will give the desired density of 10.49 g/cc. This material may be too hard to strike a coin at room temperature but preheating the blank will produce a struck coin. Electroplating with silver will give you a counterfeit that has the correct dimensions and weight. I suspect that the copper-tungsten alloy coin may even give an acceptable ring test when dropped on a table top.
The copper-tungsten requires high temperature metal alloying operation but could be procured from manufacturers by a high volume counterfeiter. I also looked at lead alloys that can be readily obtained in the market. A listing of white metal alloys available for jewlery and pewter making is given at:
http://www.alchemycastings.com/lead-...ts/jewelry.htm
Some commercially available alloys (tin %/antimony %/lead %) are:
Atlas 5842 or Linotype, density 10.62, (4/12/84),thousands of tons of this in the country from old newspaper plants
AIM 16, density 10.56, (16/3/81)
Hirsch 164, density 10.51, (16/4/80)
CMC 5/15 Monotype, density 10.44, (5/15/80)
Thus, with some adjustment, a perfect lead alloy (pewter alloy) can be blended to match the silver density. Striking a coin blank with the softer lead alloys would be relatively easy. A small volume operation may use investment casting to make the counterfeit slugs. Silver plating of the pewter can be done as was done with silverplate in the past.
China is currently producing "replicas" of 90% junk silver coinage with copper cores at a profit. It would not surprise me if better quality counterfeit coins and bullion were circulating now. The best place to pass counterfeit silver is with the small weight pieces, 10 troy ounce or less. 100 to 10,000 ounce bars may pass into a silver fabrication facility or be drilled and assayed.
I believe that good quality counterfeit copper-tungsten or pewter silver coins will be certain by the time silver hits $50 per troy ounce. Future bullion coins buys may require filing a notch and using an acid test for verification.
I will avoid all generic silver in the future and only purchase SAEs or other coinage struck by a national mint with close examination for flaws in the dies. I may buy 90% dimes as they are probably too much bother to counterfeit until the price of silver exceeds $50. I no longer purchase China Pandas because of the counterfeiting. I would not accept large bars unless they were assayed. The best vehicle for large holdings of physical metal may be CEF, Central Fund, with their in-place controls.
I am also waiting for the first tungsten cored GAEs or Krugerrands to show up. The tungsten can also be alloyed to slightly reduce the density and match 24k or 22k gold coinage.
I did some research into alloys that might come closer to the silver density of 10.49 g/cc.
I found data on various copper-tungsten alloys (used in electrical applications) and plotted the data in an excel spreadsheet. It appears that approximately 75% copper-25% tungsten will give the desired density of 10.49 g/cc. This material may be too hard to strike a coin at room temperature but preheating the blank will produce a struck coin. Electroplating with silver will give you a counterfeit that has the correct dimensions and weight. I suspect that the copper-tungsten alloy coin may even give an acceptable ring test when dropped on a table top.
The copper-tungsten requires high temperature metal alloying operation but could be procured from manufacturers by a high volume counterfeiter. I also looked at lead alloys that can be readily obtained in the market. A listing of white metal alloys available for jewlery and pewter making is given at:
http://www.alchemycastings.com/lead-...ts/jewelry.htm
Some commercially available alloys (tin %/antimony %/lead %) are:
Atlas 5842 or Linotype, density 10.62, (4/12/84),thousands of tons of this in the country from old newspaper plants
AIM 16, density 10.56, (16/3/81)
Hirsch 164, density 10.51, (16/4/80)
CMC 5/15 Monotype, density 10.44, (5/15/80)
Thus, with some adjustment, a perfect lead alloy (pewter alloy) can be blended to match the silver density. Striking a coin blank with the softer lead alloys would be relatively easy. A small volume operation may use investment casting to make the counterfeit slugs. Silver plating of the pewter can be done as was done with silverplate in the past.
China is currently producing "replicas" of 90% junk silver coinage with copper cores at a profit. It would not surprise me if better quality counterfeit coins and bullion were circulating now. The best place to pass counterfeit silver is with the small weight pieces, 10 troy ounce or less. 100 to 10,000 ounce bars may pass into a silver fabrication facility or be drilled and assayed.
I believe that good quality counterfeit copper-tungsten or pewter silver coins will be certain by the time silver hits $50 per troy ounce. Future bullion coins buys may require filing a notch and using an acid test for verification.
I will avoid all generic silver in the future and only purchase SAEs or other coinage struck by a national mint with close examination for flaws in the dies. I may buy 90% dimes as they are probably too much bother to counterfeit until the price of silver exceeds $50. I no longer purchase China Pandas because of the counterfeiting. I would not accept large bars unless they were assayed. The best vehicle for large holdings of physical metal may be CEF, Central Fund, with their in-place controls.
I am also waiting for the first tungsten cored GAEs or Krugerrands to show up. The tungsten can also be alloyed to slightly reduce the density and match 24k or 22k gold coinage.