1984???

daggit · Senior Member

Don't know about this...so an image should bring an answer from someone Very Happy

Is it just the Zinc rotting away?

coop · Expert Member

Looks like a scratch around the rim. It could have been from a coin counting machine but looks too close to be a wrapping machine issue. After the scatch was made exposing the zinc core, the air started a reaction with the zine and making it raise. This will happen for a time and then it will collapse or just develope a hole and continue to dissolve.

Rhubarb · Senior Member

Coop,

How long did it take it to fall off. I thought I had alot of time on my hands. Smile

(I do know it's 3 different coins)

Rhubarb

Dick · Expert Member

Rhubarb, you cheated! You looked at the dates. That's not fair! LOL
Dick

coop · Expert Member

Actually found them in circulation that way. The zinc disappears/swells/leaving a space no longer there and contact with other coins pushes in the copper platting and then the copper hershey's kiss shell is all there is left. I've found two so far that have the mint mark missing. I checked both of them and they don't have the same markers. Just a matter of time for the ones with the plating stretched.

KurtS · Senior Member

Those are great photos! Somehow it reminds me of sinkholes you get in places like Florida that devour homes. Anyhow, that's a different process, a different scale. Laughing

I may have mentioned this elsewhere, but something which happens between copper and zinc in the presence of an electrolyte (water, salt, acids etc.) is that copper "robs" electrons from the zinc, causing zinc to go into solution and bond with other elements such as oxygen. The white powdery stuff you see in the "rise" photo is probably zinc oxide, which occupies more space that zinc alone, forcing the thin copper plating outward which eventually cracks and exposes the core to further oxidation. This Zn/Cu combination basically creates a battery.

I suppose this explains in detail why I think a copper/zinc composition is a poor choice for the Lincoln cent. In fact, a 100% zinc penny would be more durable over time, as you've probably seen in wartime emergency money from Europe. Shocked

Dick · Expert Member

Coop, You might show a lincoln cent, about the size of a quarter, or half dollar, that , with a small voltmeter would be what we carry in out pocket change, skightly exagerated.You could label it 1982-date, barttery. That would be an avatar subject for you. LOL Wish I could type as fast as I think. Maybe some of these posts would make sense!
Dick

KurtS · Senior Member

Dick-
I'll guess you're referring to my "battery" comment. Well, it's true that there is a galvanic reaction between copper/zinc, but the voltage would be extremely tiny. Gotta remember--all metal corrosion is an electrical process. Btw--ships actually use a block of zinc to prevent corrosion to other hardware on board because of its high galvanic potential; the zinc is sacrificed to protect the expensive hardware. Too bad the US Mint doesn't understand this! Mad

Anyway...that's more needless trivia than you need to know; I'm full of this stuff! Laughing

Dick · Expert Member

Kurt, I didn't know that, (about the ships, I spent 20 years in the Navy, but never was "ships company"! I always had wings. I don't believe iron will float, so I stayed on aliminum. It does float_ As to the battery concept, Yers I am aware of that. I have been in electronics, and "Ham Radio" for most of my life. I let my license expire while in Mexico, because I don't type, or write fast enough to take the test for "Extra Class" license, (I had the advanced class), Between Auto, and avation Mechanics, and electronics, My life has been with tools of one class, or the other. Dis=similar metals, always have a chemical reaction, and the eler=ctrical charge can be measured, with the right instruments. I am cpomfortable with reciprocating engines, auto, or aircraft, but I don't like the jet engine, (no more that the diesel engines that replaced the steam engines, in '46/'47). I fired the steam engine, but quit, and went back into the Navy when the stinking diesels came, in '47! Kinda strayed afield! Sorry Chuck.
Dick

coppercoins · Site Admin

coop's coins in this thread are from something different than the coin in the post that started the thread. The coin in the original post is also obviously not from coin counter damage nor is it scratched. The raised area in question was caused by die wear.

Dick · Expert Member

Chuck, looking at the area in question. It looks a lot like the "raised area" that is often seen on the edge of some of the coins frome the "mid-late '80's"... Could it be a very late condition, from the zinc deteriorating, due to the air leaking thru minute holes in the plating? The shape of the "crack", and the location look very familiar. What do you think?
Dick

coppercoins · Site Admin

I have never given it much thought because it's common, doesn't generate any value in the coin, and is unattractive. It wouldn't sell as an error coin to anyone for much of anything. I've always skipped stuff like this for these reasons.

I could analyze everything I see that's soewhat unusual and keep everything that looks a little odd, or I could concentrate on pulling out and keeping coins that have widespread interest and value. I just prefer to do the latter, and don't question the others.

mikediamond · Advanced Member

It's a planchet defect, but I don't know whether it's restricted to the copper plating or extends into the zinc core. I"m not sure what type of defect it is, but it's interesting.

Dick · Expert Member

Mike, Chuck, thanks for your comments. My position is curiosity, more than anything else, due to my relatavely brief experience.
Dick