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 Replies: 30 / Views: 4,168 |
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Pillar of the Community
 United States
3925 Posts |
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New Member
United States
9 Posts |
 The top left is a 1946 shell casing cent compared to other cents in my collection, its actually how I learned about them the off color caught my eye, although finding them in this tone doesn't happen very often.
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Moderator
Australia
16332 Posts |
The standard definition of "bronze" is "an alloy of copper and tin". The presence of tin makes the difference between brass and bronze. As such, the 5% zinc alloy used for these coins technically makes the alloy a "brass", rather than a "bronze"; the overall more yellowish appearance often found with these coins bears this out.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Pillar of the Community
United States
3925 Posts |
The "shellcase" coins were not made of 100% shellcase brass, as far as any of the references state. Just a small percentage of spent shellcases were added to the mix, presumably more as a PR ploy. I doubt there was enough zinc added to justify calling these "brass", but maybe some coins were made with 100% shellcase brass, who knows? The main distinguishing feature I've noticed is bright and unusual toning colors, often streaky or splotchy, that appear to me to be due poor mixing during the alloying process. These colors are consistent with metals found in other parts of the used shellcases, especially the primer materials, but I've never seen a definitive XRF assessment of a "shellcase" Cent to be sure.
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
 United States
4380 Posts |
There is a lot of noise out there... RWB has the info in his book and a summary in a posting on the PCGS board. See: https://www.numismaticnews.net/arch...ger-burdetteThe book is on sale @ Wizard for a nickel under $30. and Quote:
The mint tried several ways of handling bronze shell cases. The casing alloy was commonly 85% Cu and 15% Zn. Brass did not work very well for direct recycling - it became too brittle. In later 1943 box car loads of shells came into the San Francisco Mint. In melting these, the mint found that there was too much zinc volitization, plus the mints were not set up for mass melting of this material. Eventually, the casings were sent to a Mint contractor who melted them into bars of about 1,000 oz. and 10% zinc. The mints melted these and added sufficient pure melted copper to bring the alloy to standard. This occurred through 1947 and likely later.
Archive documents refer only to use of domestic shell casings from training camps, however there is some anecdotal material indicating savage of 5-inch naval shells.
Copper-based coinage alloys are subject to a wide range of discoloration. This can be attributed to environmental factors, contamination and heat, among many.
To me, the real story is much more interesting and valuable than any imaginary concoction. -----Burton 50 year / Life / Emeritus ANA member (joined 12/1/1973) Life member: Numismatics International, CONECA Member: TNA, FtWCC, NETCC, OnLine Coin Club Owned by four cats and a wife of 40 years (joined 1983) |
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Pillar of the Community
United States
4380 Posts |
-----Burton 50 year / Life / Emeritus ANA member (joined 12/1/1973) Life member: Numismatics International, CONECA Member: TNA, FtWCC, NETCC, OnLine Coin Club Owned by four cats and a wife of 40 years (joined 1983) |
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Pillar of the Community
United States
3925 Posts |
That's very interesting! Had not seen this reference. Weird they might make a whole batch of Cents with large Ag content, but bigger mistakes have been made.
We do know that San Francisco had a different smelter, or did it themselves, versus P and D mints. From the numismatic evidence, I've only seen the bright discolorations on S mint Cents, so I'd conclude they were not as carefully alloyed/mixed, or perhaps only San Francisco was tasked with the shellcase Cent PR ploy. In any event, an nice SF mint Shellcase Cent is a beauty to behold.
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Moderator
United States
164019 Posts |
Very interesting and thank you for sharing, Burton!  |
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Moderator
United States
71805 Posts |
Now I need to be on the look-out for these. I wouldn't mind having some.
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Pillar of the Community
United States
2026 Posts |
When I first began learning about coin collecting, I began with Lincoln cents. My dad had his own Whitman folder he used when he was a kid. He had a full set of BU 1944-1946 cents he got new from circulation. I immediately saw how they had a slightly different color than a typical red BU cent of the time. These were kind of a darker red with perhaps a splash of violet thrown in.
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Bedrock of the Community
United States
19672 Posts |
Quote:
These colors are consistent with metals found in other parts of the used shellcases, especially the primer materials, but I've never seen a definitive XRF assessment of a "shellcase" Cent to be sure. I would have loved to provided that XRF data. The best method would be by using an SEM-EDXRF system. It's much easier to control the source beam location with the microscope and we can area average on the fly. The issue for me was always that the analysis takes too much time on a $300+k instrument. I hate back logging work for my entertainment. lol
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Bedrock of the Community
United States
19672 Posts |
Lincoln Cent Lover!VERDI-CARE™ INVENTOR https://verdi.care/
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Bedrock of the Community
United States
19672 Posts |
Edited by BadThad
05/08/2025 7:49 pm
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Pillar of the Community
United States
3925 Posts |
As @jpsned notes, many of the shellcase coins seem to have some indigo/violet/bright blue toning. This is presumably from contamination due to the primers, but only an EDX would show that for sure. Like @BadThad, I never had opportunity to run EDX due to heavy workload on the equipment. Personal projects were frowned upon.
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Moderator
United States
164019 Posts |
Quote:
The issue for me was always that the analysis takes too much time on a $300+k instrument. I hate back logging work for my entertainment. lol King of the Lab.  Nice examples!
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Replies: 30 / Views: 4,168 |
First Page
Posted 08/23/2023 09:22 am
