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 Replies: 15 / Views: 1,259 |
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Pillar of the Community
United States
626 Posts |
Hi all, is it the zinc rot playing tricks with my eyes, or am I seeing an RPM on this '87 Memorial?  |
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Pillar of the Community
United States
4809 Posts |
Have you checked at Coppercoins? That zinc rot will ruin collect ability to the greater extent. Might be a CC rotated MM.
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Moderator
 United States
56855 Posts |
I don't think it's an RPM. It is zinc rot causing the MM to sink in and collapse,it's on the date also. John1  Edited by John1
03/31/2015 3:44 pm
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Pillar of the Community
 United States
626 Posts |
I couldn't find a match on any of the online references that I know of, nor in any of my several reference books. That led me to lean toward zinc rot, but the separation on the mint mark wants me to believe it is an RPM. I hadn't noticed the date starting to resemble the mint mark. Perhaps it should weigh less if that much zinc has been lost?
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Pillar of the Community
United States
1915 Posts |
I am with John, not an RPM
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Bedrock of the Community
United States
62064 Posts |
Split plating is the cause. Zinc rot is what your are seeing.
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Pillar of the Community
United States
626 Posts |
So if I am understanding correctly, the plating split during strike, allowing the zinc to rot (all of which is obvious), and then as the zinc deteriorates it allows the copper plating to collapse creating a valley instead of a true RPM having true separation making more of a defined trench if you will..?
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Moderator
United States
56855 Posts |
 John1 |
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Pillar of the Community
United States
3644 Posts |
I see this on a lot of the 80's cents on all the devices and used to swear I was seeing seperation/doubling on a lot of them
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Moderator
United States
23522 Posts |
Quote:
That zinc rot will ruin collect ability to the greater extent. Kinda tough to collect coins which have a finite lifespan, isn't it? At least, it is for whoever follows the first collector. |
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Pillar of the Community
United States
5964 Posts |
I thought this was a rpm. It is split plating.  |
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Pillar of the Community
United States
1915 Posts |
You have to understand, the mint did not really perfect the minting process for zinc coins until around 1994. So many of the 1989 to 1993/4 cents seem to have a lot of plating issues.
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Pillar of the Community
United States
5964 Posts |
Yes, but zinc is still inferior compared to copper. It deteriorates rapidly, faster than copper. The "blue hue" is oxidized zinc.
The reason they put copper plating on to begin with is because they didn't want to shock the public with all that junk zinc.
Edited by CoinMasters
04/01/2015 10:22 pm
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Bedrock of the Community
United States
62064 Posts |
I think the mint mark punch was to blame for these on the Zincolns. When it was punched it left a small find on the area. That is probably what split the plating until the fin flatten. With the mint mark as part of the design, then this stopped happening. IMOHO
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Moderator
United States
23522 Posts |
Heh. The reason these are plated is because zinc is so reactive it's used as a sacrificial anode. It will corrode away on its' own just laying there.
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Pillar of the Community
United States
5964 Posts |
Yes, the punch stretched the thin layer of copper, splitting it. This allowed air to contact the zinc, hastening it's demise. Indeed it also corrodes just laying there. I metal detect as well as roll hunt. I dig up Indian Heads in much better condition than 2013 Zincos. They come up "chewed" in half.
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Replies: 15 / Views: 1,259 |
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Posted 03/31/2015 3:41 pm
