Copper Sintered Nickel? - Coin Community Forum

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Author	Replies: 11 / Views: 5,645
Nelrak Pillar of the Community United States 974 Posts	Posted 08/11/2008 01:10 am I have this nickel and after researching online, I believe it to be Copper Sintered. I almost thought it was a wrong planchet nickel on cent when I first saw it but it's definitely nickel diameter. The best definition I have found for this "Mint Error" is: Quote: "Sintering: The welding together of small particles of metal by applying heat below the melting point. Typically occurs during the annealing process of coin planchets when the annealing drum has not properly cleaned and minute amounts of the previous medal (like copper) are left behind in the drum. Notable examples are the sintering of nickel coins were copper adheres to the nickel finish of a planchet giving it a gold tint or copper colored finish." Anyone care to comment? Edited by Nelrak 08/11/2008 5:46 pm Report this Post to the Staff

jbuck Moderator United States 187950 Posts	Posted 08/11/2008 6:04 pm I anxiously await the expert opinions on this one! Coin Collector Since 1978 Avatar Old Avatar 7070 Eisenhower Australia Canada World CCF Members on eBay CCF eBay Search Engine Report this Post to the Staff
foundinrolls Pillar of the Community United States 3507 Posts	Posted 08/11/2008 6:17 pm It is unwise for me to suggest with 100% certainty that this coin is struck on a sintered planchet without having looked at it closely. It does appear to be. I would only caution that in some lines of work, lithography, for example, chemicals are used that deposit copper onto other metals. I suspect that this coin is indeed struck on a sintered planchet but I wanted to mention the other possibility. Thanks, Bill Report this Post to the Staff
mikediamond Pillar of the Community United States 2734 Posts	Posted 08/11/2008 10:21 pm It looks like an authentic improper annealing error. However the "sintered planchet" and "copper wash" scenarios are examples of numismatic mythology. No one appears to understand why a copper layer forms on coins that are baked too long (or at too high a temperature) in the annealing oven. Since some of these nickels are appreciably underweight, an added layer of copper is a non-starter. There are many other objections to the sintering scenario, but it would take several pages to go into them all. Perhaps the copper fraction of the alloy migrates to the surface. Perhaps the nickel fraction migrates to the interior, leaving the copper fraction at the surface. Perhaps the nickel fraction is liberated, leaving the copper fraction behind. Perhaps the copper fraction is liberated and re-deposited as a pure layer. I really don't know. Even a metallurgist I talked to can't figure it out. Error coin writer and researcher. Report this Post to the Staff
foundinrolls Pillar of the Community United States 3507 Posts	Posted 08/11/2008 10:25 pm Hi Mike, Thanks for going into that part of it. After my thread on the 1949 S cent, I wasn't ready to tread these waters :-) Have Fun, Bill Report this Post to the Staff
Nelrak Pillar of the Community United States 974 Posts	Posted 08/12/2008 10:48 am Thanks Mike and Bill. So I take it this would not be something TPG Companies would be able to confirm? It does have some nice eye appeal. Report this Post to the Staff
mikediamond Pillar of the Community United States 2734 Posts	Posted 08/12/2008 10:53 am They slab these all the time. The label varies, however. Sometimes it's called "improperly annealed", sometimes "sintered plating", and sometimes "copper wash". It's a reflection of their uncertainty over the etiology of this error. Error coin writer and researcher. Report this Post to the Staff
jbuck Moderator United States 187950 Posts	Posted 08/12/2008 10:59 am Thank you, Bill and Mike, this has been an interesting read. Coin Collector Since 1978 Avatar Old Avatar 7070 Eisenhower Australia Canada World CCF Members on eBay CCF eBay Search Engine Report this Post to the Staff
BadThad Bedrock of the Community United States 19935 Posts	Posted 08/12/2008 3:28 pm Beautiful coin! Lincoln Cent Lover! VERDI-CARE™ INVENTOR https://verdi.care/ Report this Post to the Staff
chuckster 125 Pillar of the Community United States 4113 Posts	Posted 08/24/2008 02:00 am Nelrak- Great looking Coin! Here are pics of 2 Jeff Nickels I have, one is a 89P and the other is a 2004P, both are copper colored, how can you tell if this is naturally toning or they have been sintered? The 89P I've had since 1989 (Nice Steps) and the 2004P I just found a few days ago in rolls. Image: 1989PJeffersonObvjpeg1.jpg 37.9 KB Image: 1989PJeffersonRevjpeg1.jpg 44.56 KB Image: 1989PNiceltonedstepsjpeg3.jpg 51.65 KB Image: 2004PJeffersonjpeg2.jpg 48.64 KB Image: 2004PJeffersonRevjpeg1.jpg 58.93 KB Report this Post to the Staff
mikediamond Pillar of the Community United States 2734 Posts	Posted 08/24/2008 08:59 am Again, I prefer the term "improperly annealed", since the sintering scenario is unworkable. Anyway, your two coins look like legitimate examples. Both retain original mint luster, which is key. Error coin writer and researcher. Report this Post to the Staff
chuckster 125 Pillar of the Community United States 4113 Posts	Posted 08/24/2008 12:58 pm Thanks Mike! I'll try to remember to refer to these as "Improperly Annealed" from now on and avoid using the word sintered. Thanks again, Chuck. Report this Post to the Staff
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