Were proof 1982-S Lincolns struck on bronze or zinc planchets?

seanq

Trying to determine which planchets were used in production of the 1982 proof Lincoln cents, and I am finding conflicting information. PCGS has them listed with the copper coins (1959-1982), while the entry on NGC says they were struck on copper-plated zinc planchets.

I do have a reason for asking, which I will share when the coin arrives. The coin I purchased is in an NGC holder without the weight listed on the insert.

Sean Reynolds

MarkKelley

All were bronze.

telephoto1

All proofs were bronze.
Edit to add...Oops! someone else already covered this.

jmlanzaf

@MarkKelley said:
All were bronze.

We should probably break them all out and weigh them to be sure...

MWallace

Were proof 1982-S Lincolns struck on bronze or zinc planchets?

Yes.

ricko

Weigh the coin in question.... 3.11 vs 2.5..... Cheers, RickO

seanq

@ricko said:
Weigh the coin in question.... 3.11 vs 2.5..... Cheers, RickO

Hard to weigh it in it's current home:

Sean Reynolds

Batman23

Looks like it might come up a little light anyway...

Nice error.

gumby1234

That must be one of the smallest clips in existence.

MrScience

You could crack it out, of course, but there should be some noncontact / noninvasive methods - such as those based on ac magnetic fields - to infer if the coin has a zinc core. For example, maybe a metal detector could be used to do an A/B test with this cent and other slabbed cents of known composition?

telephoto1

...Or you could just weigh coin and slab together and deduct the weight of the slab.

numisma

Can you show us an angular close-up photo of the clipped area? On a copper-plated zinc planchet, you would see a touch of white material on any breached surface. The plating is thin. Your clipped planchet example looks like a bronze.

However, it is my understanding that all of the 82 proof Lincolns were struck on bronze planchets.

seanq

@numisma said:
Can you show us an angular close-up photo of the clipped area? On a copper-plated zinc planchet, you would see a touch of white material on any breached surface. The plating is thin. Your clipped planchet example looks like a bronze.

However, it is my understanding that all of the 82 proof Lincolns were struck on bronze planchets.

The zinc core is not visible on any genuine clipped planchet, as the copper plating process took place after the planchets were punched. The inside of the clipped edge will be copper on any genuine error.

Sean Reynolds

numisma

The zinc core is not visible on any genuine clipped planchet, as the copper plating process took place after the planchets were punched. The inside of the clipped edge will be copper on any genuine error.

@seanq that makes perfect sense now that I think about it. But aren't the planchets polished for proof cents? In the subsequent years of copper-plated zinc cents (1983 onwards), how does the mint obtain the mirrored finish on the blanks? I know that the proof dies are polished, but I have always understood that the proof planchets were also specially prepared.

CaptHenway

IIRC, the 1982-S Proofs were 95% copper and there was some talk about continuing the 95% copper composition for the Proofs indefinitely after that, but it did not happen.

jesbroken

CoinFacts shows the 82S Proofs as being 95% copper and 5% zinc. So, is that correct or not?
Jim