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Moderator
 United States
34441 Posts |
Quote:
I really want to know what kind of acid causes this. Here you go: Quote:
Copper is an unreactive metal and doesn't react in normal circumstances with dilute acids. However, it does react with nitric acid. Why is this?
Nitric acid is an oxidizing agent and the reaction is not the usual acid + metal reaction. The products are oxides of nitrogen instead of hydrogen. The actual nitrogen oxide formed depends on the concentration and temperature of the acid. from here: https://chemistry.stackexchange.com...-nitric-acid"If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz
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Valued Member
 United States
68 Posts |
I was in line at the Bank, behind a woman that deposited a bunch of rolled coin. No Halves, though.  I bought $11.50 worth of Cents and pulled only 3 Wheaties and about 3 rolls of copper Cents out of the bunch. I'm about blind from searching them at one sitting. |
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Rest in Peace
10197 Posts |
Looks like metal etching solution, hydrochloric if I remember right. A high school science project that Little Johnnie in the Garage needed to do to graduate into Bomb-making 101.  ...Bang...  Edited by Crazyb0
08/12/2017 5:38 pm
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Pillar of the Community
7234 Posts |
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Copper is an unreactive metal and doesn't react in normal circumstances with dilute acids. Maybe the acid used only reacted with the 5% tin/zinc? Hence the details and the mostly smooth edges are still there? Edited by Mark1959
08/12/2017 5:45 pm
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Moderator
United States
34441 Posts |
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Maybe the acid used only reacted with the 5% tin/zinc? Yep I'm not sure. Not that I'm advocating destroying copper cents, but it might be an interesting experiment to look at the effect of different acids/concentrations/exposure times/temperatures.  "If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz
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Moderator
United States
56855 Posts |
Looks like heat to me. Maybe a blow torch. John1  |
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Valued Member
United States
186 Posts |
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Maybe the acid used only reacted with the 5% tin/zinc?
Hence the details and the mostly smooth edges are still there? I was looking for something like this just because I thought it would bring out the dates on my dateless LWCs. It's because the tin and zinc are much softer than the copper. |
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Pillar of the Community
7234 Posts |
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Looks like heat to me. Maybe a blow torch. When you say blow torch do you mean Oxy/Acetlene (that I've melted glass with) or those propane soldering torches - I have one on my porch that I use to light my charcoal, I could try it out right now and post pics!! |
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Rest in Peace
10197 Posts |
Most acid dipped coins lose detail instead of improving it like in rasised date Buffalos. John1 may be right...if acid is used, the rim dissolves first(outside in). Extreme heat (2000+°) will burn off impurities and cause that mottled effect, I change my vote to heat!
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Pillar of the Community
7234 Posts |
OK - not Oxcy/Acetylene nor hand held propane welding torch. First one is Oxy/Acetylene - melted the coin in 5 seconds. Second one is 5 mins of heat applied from hand held propane torch! - nothing!! Yes, 95% copper cents were used! Must be from "Propane and Propane Accessories" - AKA Hank Hill - LOL!   Edited by Mark1959
08/12/2017 7:11 pm
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Bedrock of the Community
 United States
12862 Posts |
Wow, the torch really did a number on that cent! Ouch!
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Pillar of the Community
7234 Posts |
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Extreme heat (2000+°) will burn off impurities and cause that mottled effect, I change my vote to heat! Pure copper melts at 1983F - then with the addition of 5% zinc/tin brings that temperature down a touch. |
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Pillar of the Community
7234 Posts |
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Wow, the torch really did a number on that cent! Ouch! Yeah , I was surprised it just got gone, I thought it would melt and spread! |
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Moderator
United States
189767 Posts |
I agree, probably corroded. It is an interesting find. Thank you for sharing.  |
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Pillar of the Community
5464 Posts |
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Posted 08/12/2017 5:33 pm
