1984-D Zinc Rot Oddity - Coin Community Forum

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Author	Replies: 3 / Views: 1,960
Drav3n New Member United States 28 Posts	Posted 06/03/2013 04:17 am Just wanted to get some input on this coin. Found it quite odd, as how obvious the damage was even to the naked eye. I am quite well aware of the zinc rot taking place around the bottom of the mint mark. But look around it as the area around the mint mark is completely raised. I want to see if my assumption could be correct. Possibly grease buildup around a cracked/broken die or a chip that became so great that it created a raised mound around the mint mark? Thus creating a weak area allowing zinc rot to set in? I just found it neat and thought I would get some input and feedback from the community. Report this Post to the Staff

seal006 Pillar of the Community United States 1915 Posts	Posted 06/03/2013 04:40 am Most likely the raised area is just from the plating bubbling up. As the zinc rots it expels a gas. The copper plating layer is very thin and pliable. As the gas is released it causes the copper layer to rise. Report this Post to the Staff
Drav3n New Member United States 28 Posts	Posted 06/03/2013 05:04 am Makes sense, thank you. I did not think about possible fumes or gasses being released but if a chemical reaction is taking place then certainly some by-product is expelled as a result of the reaction. Heat, if nothing else.Thank you. Report this Post to the Staff
Conder101 Bedrock of the Community United States 17884 Posts	Posted 06/03/2013 2:01 pm During the strike the plating splits by the mintmark alowing water and air to get it. This leads to "zinc rot" or corrosion as the zinc combines with the air and water to create zinc oxide. Zinc like iron spalls as it corrodes, the corrosion products puffing up and flaking off as it corrodes. The problem here is corroding zinc is held in place by the plating so it swells up creating the bulging areas under the plating. Have you ever seen a car rusting under the paint job where the rust hasn't broken through to the surface? You see the same type of bulges under the paint. then one day it breaks through the the rust starts flaking away. Report this Post to the Staff
	Replies: 3 / Views: 1,960

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