Post your Lincolns!

Here's a BIE That I got in change today.

 

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Recently found this Lincoln.

 

Nice coin

 

That is one solid 1911 Lincoln.

 

1989-S Proof

 

I like the field above the ONE CENT

 

That's a BUTE! I'm guessing you would call it metal flow lines. I have a few like that and when you turn them in the light, I love it!

 

Some of today's hunt

 

Those aren't metal flow lines. They are bubbles trapped between the layers of copper and zinc.

 

Thanks Bob! Are they eventually the death of the coin or if you store it correctly will it remain in that condition?

 

That's a good question. Just about all the proofs from the early 80's have this. I think the condition is fairly static. They came from the mint like this so it's not like it has developed over the years. Mine look the same way today as they did when I first got them.

 

I only have experience with the early '90's that I have purchased and it is very pronounced in those.

 

I'm not sure if this is the same mechanism as the bubbles that plague the early copper-zinc business strikes.

I believed those were better characterized as bubbles if they were separations of the copper cladding from the underlying zinc. I do wonder what was in those bubbles, or if the metals merely separated and created a small chamber of near-vacuum between the layers - namely, the bubble could not contain any air unless it was punctured.

On these proofs, I don't feel like the layers have separated. (Disclaimer, I don't know anything about metallurgy.) I would speculate that these were ripples caused by differences in the rate of plastic deformation during striking due to the different densities and metallic crystalline structures of thin-film copper (I've heard it's about 20 microns thick) and the much thicker core of zinc underneath.

Is there a metallurgist on the forum? I'd really like to know!

Here's a 1982 Zincoln. To me these look like bubbles, where the proof looks like waviness or ripples.

 

Great haul

 

Great job ron. I'm not buying the bubble thingies.

 

That's a rainbow toner! Get those colors popping on your camera!

View attachment 856340

 

Proofs are struck at greater pressures on pre-polished planchets with fresh, highly polished dies. That process tended to smooth out the surfaces more than a business strike. As I recall, the planchets were exactly the same, they simply added an extra polishing step for the proofs. Therefore, the amount of gas inside the clad layer would have been essentially the same for proofs and business strikes.

OK....down to it....

The wavy lines found in proofs are from the underlying gas AND from a soft zinc core with minor imperfections on the surfaces (they can't polish the zinc core). These simply manifest themselves differently - more smoothly - on proofs due to the above.

As to why the bubbles exist? I have some boring technical theories involving impurities, galvanic corrosion and water in the core.

 

1990-S Proof
Alrighty then, let’s see a couple more.





Edit: Ya know, I like the added texture to the fields. I think it adds a bit of design and interest to an otherwise empty area.