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[La_isla]

Hi All -

New to the site and appreciate all the expertise associated with NGC.  I recently found what I originally thought was a 1998 Lincoln cent that was sanded down but now after seeing a couple of examples of NGC graded coins with plating errors I'm not so sure.  Reason for my uncertainty is along the rim it appears lower unexposed areas of the coin appear that the copper plating did not adhere.  There are clearly more prominent areas (cheek, temple, chin, nose and lapel) where zinc is exposed.  There are no indications of scratching I would associate with the use of sand paper in these areas.  There also doesn't appear to be dissolving liquid solution used where the lower areas would also be affected. 

If this is a plating error what factors are at play?

Feedback would be appreciated.  Thank you for your opinions in advance.

La_isla

[JKK]

Heavy wear on high points, whether deliberate or accidental. No reason to see it as a plating error. More likely it was caught between abrading surfaces for a brief time, long enough to grind through the Cu which is however many microns thick. The coin is damaged and of zero interest to most collectors, and would command no premium above 1c.

[La_isla]

Agree, whether intentional or not, some of the higher points on the coin lack Cu.  It was the areas that are not prominent and below level without Cu that caught my attention.  Thanks for your feedback.  

Edited April 12, 2022 by La_isla
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[Coinbuf]

Welcome to the forum, you do not have a plating error 100% guaranteed on that.   How exactly the coin became damaged is known only by the person that created the damage.   Do you have photos or links to those coins you saw that led you to beleive this could be a plating issue?

[Oldhoopster]

Your original thought was correct.  It's abraded after it left the mint.  Notice how the plating is only missing on the high points but the slightly recessed areas of the adjacent hair is plated

Copper plating is an electrochemical process.  Incomplete plating nonconformances from contaminated/unclean planchets and/or process variability aren't limited to the extreme high points.  In fact, that would be incredibly unusual.

Also, I bet if you look real close, you can see scratches on the exposed zinc.

 

 

[La_isla]

What is/are the cause(s) of plating issues?

[Oldhoopster]

For the common plating bubbles and blisters, it's usually poorly cleaned zinc blanks or dirty/contaminated plating solution.  Bubbles and blisters aren't considered errors and have no value.  

Missing plating errors are uncommon and very hard to find if you're searching rolls/pocket change.  They can be caused by hiccups in the manufacturing process (electrical, chemical, operator error, etc)

BTW: if you do a little digging on the net, you can find ways to remove the plating on cents.  The plating is nominally only 8 microns thick (0.0003")

[La_isla]

Great information Oldhoopster.  Thank you.