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DuPont Explosion Bonded Quarter Pattern
September 13, 2007

Patterns at Heritage Long Beach Sale

Session Five of the upcoming Heritage Long Beach Auction contains a nice run of United States patterns. There are some of the classic pieces such as the popular Judd-1655 Coiled Hair Goloid Metric Dollar in copper and a Judd 346 Seated Liberty muling also in copper. These types always generate high interest, but this grouping also has a few more obscure pieces well worth the look.

An outstandingly sharp strike of the Liberty Head nickel design for a proposed alloy change to 50% nickel and 50% copper, Judd-1710, is offered as lot 3033. This pattern piece grades proof-67 and is a real dazzler. There are several International Nickel Company Inc. strikes from 1964 when the U.S. Mint farmed out some of the composition testing for new nickel based coinage brought on from higher silver bullion prices. Many of these pieces were designed by Gilroy Roberts and hubs produced by the Medallic Art Company. Some were struck by General Numismatics, which evolved into The Franklin Mint. All display Dr. Paul D. Merica of INCO on the obverse and the INCO laboratory on the reverse. This sale contains one of the Dimes from this series and three of the quarters including one of the scarce type three patterns with the revised design pictured here.

Finally this sale contains an undated DuPont Benjamin Franklin quarter pattern produced in 1964 under the same U.S. Mint program as the INCO pieces. In their search for a replacement for silver, DuPont experimented with a patented method called Detaclad. Detaclad was a process of explosion bonded laminating designed to adhere 75% copper onto 25% nickel. Judging by the results on this piece, it must have worked pretty well. DuPont eventually supplied 70 million pounds of Detaclad coin blank stock to the U.S. Mints in Philadelphia and Denver during the 1960's. This was a great start for the new Detaclad division which DuPont built up to an 11 million a year business before selling it to Dynamic Materials Corporation in mid 1996.

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About the Author
Tom Michael has been Krause Publications primary market analyst on more than 80 world and United States coin catalogs produced over the last 20 years. He came to KP in 1987 with a bachelor of arts degree in history, a master of arts degree in economics and a history of coin collecting stretching back to the 1960s. He began collecting world coins as a child by asking friends and relatives to bring coins back from overseas trips, visiting flea markets and having his mother watch for foreign coins in her register at the local grocery store. Today he works with a dedicated base of over 200 contributors to provide accurate market values for the five-volume Standard Catalog of World Coins series, as well as many specialty catalogs, including Coins & Currency of the Middle East and the fifth edition of Unusual World Coins.

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