Clad Proof Ike with spiderweb cracking in the fields.

Aspie_Rocco

Is this common? I have not noticed this surface condition before, not much experience with proof Ikes. I noticed it with a 10x loupe. Close ups are 30x. It was hard to image these and the cracks are more dramatic than I can show with pictures. No cracks on the reverse fields and none on devices (portrait, letters, numbers frosty.

OAKSTAR

I'm not an expert but that doesn't look common or normal to me. Looks like some type of stress marks. Maybe planchet issue??

AUandAG

Heck, I was thinking a rough polishing of the die.

bob

tincup

The geometric 'squares' are rather puzzling...

lilolme

@Aspie_Rocco
Can you confirm if these are raised or into the field?
I see them both ways depending on the picture I am looking at.

Aspie_Rocco

@lilolme said:
@Aspie_Rocco
Can you confirm if these are raised or into the field?
I see them both ways depending on the picture I am looking at.

They are raised, or convex.
Not polish lines, looks like broken glass or an irregular reptile skin pattern.

lilolme

@Aspie_Rocco said:

@lilolme said:
@Aspie_Rocco
Can you confirm if these are raised or into the field?
I see them both ways depending on the picture I am looking at.

They are raised, or convex.
Not polish lines, looks like broken glass or an irregular reptile skin pattern.

Thanks.
First I do Not know this stuff (die things). But I will take a stab at it.

It looked like the less magnified pictures might have had die erosion or something similar.

Then on the blow ups, the lines when they stopped almost always stopped at another line. Example a horizontal line when it stopped it stopped at a vertical line. Like a cracking or crazing.

So I went looking for something like that and found this in your Resources.

https://www.error-ref.com/die-crazing/

So that is my Guess as to what it is.

sumdunce

Didn't they chrome plate the proof dies for the late 70s Ikes? That could be a problem with the chrome plating on the dies.
Just a guess...

Aspie_Rocco

If it was not already in a PR69DCAM holder I would think it is a problem coin. I am intrigued with the idea of a chromed die.

lilolme

@Aspie_Rocco said:
If it was not already in a PR69DCAM holder I would think it is a problem coin. I am intrigued with the idea of a chromed die.

If these are chrome plated, then I went looking into chrome plating, I find that sources will mention potential problems with the process. One of which is hydrogen embrittlement in the steel. Sources mention that the plating process can introduce Hydrogen (H) to the steel and then this can cause the hydrogen embrittlement under the right or wrong conditions. I could not find any pictures of this cracking at a surface but there are some failure pictures and some drawing type pictures and descriptions of it.

Hopefully one of the metal people on the forum will find this thread.

https://www.metallurgyfordummies.com/hydrogen-embrittlement.html

https://www.imetllc.com/hydrogen-embrittlement-steel/

jesbroken

@lilolme

Not sure if these articles are basically for steel only, and not coin metal. Even the 43 D Lincoln was steel. Not saying it can't happen to coin metals but not as likely.
Jim

BuffaloIronTail

I always thought that micro-cracking was a result of the proofing process. I read that somewhere and remember seeing it mentioned somewhere else.

Pete

lilolme

@jesbroken said:

@lilolme

Not sure if these articles are basically for steel only, and not coin metal. Even the 43 D Lincoln was steel. Not saying it can't happen to coin metals but not as likely.
Jim

I went looking for chrome plating and then found the information for plating of steel. The thought being that the chrome plating of the steel die might not have been done correctly and created the condition on the die to where the die began to crack after striking.

I don't even know if the die is chrome plated. So the rest is certainly me just looking stuff up and throwing it out there. Just know that AR said the lines on the coin in the picture are raised and guessing stuff from there.

privatecoin

Very interesting indeed.

CaptHenway

My first thought was that the coin had been coated in some sort of lacquer that had crackled.

cameonut2011

@CaptHenway said:
My first thought was that the coin had been coated in some sort of lacquer that had crackled.

Wouldn’t that impede the mirrors and wouldn’t it have been super obvious to the graders?

CaptHenway

@cameonut2011 said:

@CaptHenway said:
My first thought was that the coin had been coated in some sort of lacquer that had crackled.

Wouldn’t that impede the mirrors and wouldn’t it have been super obvious to the graders?

I have no better guess.

JBK

There was a discussion some years ago about a "spiderweb" sort of "growth" that developed on some or proof coins. I am not sure it was ever figured out what it was.

Your proof coin here is more subtle and I am not sure it's the same effect as discussed in the other thread. Maybe scratches from an abrasive partial dragged across the die during hand-polishing?