is this a greaser or pmd?

[griffith 90]

i'm still learning about errors so any info would be helpful. found this 1991d in a roll today. Want to know if its a true struck through grease. If it is what is value.

 

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[dejapooh]

I'm guessing it is an incomplete laminate of the copper onto the zinc. I guess you could get the same result from heat as PMD, but the color would likely be effected too...

 

[enamel7]

Looks like heat damage to me!

 

[port ewen ace]

found a few Zincolns from '83 & newer with the "Colonel Kurtz" look, my guess is massive gas bubbling of the clad layer on both surfaces. bet the bumps collapse when ya' push on 'em

 

[huntsman53]

IMHO, poorly prepared Zinc planchet which did not allow for good adhesion of the Copper plating thus creating air or gas bubbles underneath. Excessive heat transferred from the Dies to the planchet during the minting process, may have aided the separation.


Frank

 

[griffith 90]

found a few Zincolns from '83 & newer with the "Colonel Kurtz" look, my guess is massive gas bubbling of the clad layer on both surfaces. bet the bumps collapse when ya' push on 'em

they're solid

 

[griffith 90]

IMHO, poorly prepared Zinc planchet which did not allow for good adhesion of the Copper plating thus creating air or gas bubbles underneath. Excessive heat transferred from the Dies to the planchet during the minting process, may have aided the separation.


Frank

would it be worth keeping?

 

[huntsman53]

would it be worth keeping?

It is up to you! They are definitely odd and somewhat conversation pieces in trying to envision scenarios and conditions that could have caused the effect and some folks do collect them.


Frank

 

[griffith 90]

It is up to you! They are definitely odd and somewhat conversation pieces in trying to envision scenarios and conditions that could have caused the effect and some folks do collect them.


Frank

thank you

 

[SorenCoins]

This is when during the minting process they were casting the hot zinc which released fumes, of zinc oxide. This got trapped under the copper plating. So yes, technically it is a mint error. I keep only major examples of this as it doesnt have to much additional value

 

[enamel7]

This is when during the minting process they were casting the hot zinc which released fumes, of zinc oxide. This got trapped under the copper plating. So yes, technically it is a mint error. I keep only major examples of this as it doesnt have to much additional value

Casting the hot zinc? What are you talking about?

 

[huntsman53]

https://www.treasury.gov/about/education/Pages/manufacturing.aspx

 

[SorenCoins]

I meant when they are heating the planchet for an easy strike

 

[enamel7]

They don't heat the planchets before striking.

 

[dejapooh]

I meant when they are heating the planchet for an easy strike

They heat the blanks before striking. I once took a tour of the mint as part of an ANA program. There was no heating of the blanks (this was back in about 1980). The heat necessary to make any appreciable change in striking would be extreme (red hot to white hot), and the damage to the finish would require polishing after striking. I can see that being useful in High Relief issues, but for something this low, very doubtful.