1995 Lincoln Memorial Incomplete Plating

I'm with Cujohn on this one, and have posted to that effect previously. The cigarette lighter theory is just, well, silly.

I have found far too many of these cents in rolls for them to be the work of vandals. None of the coins I've found have had any evidence of carbon/soot on them, which would almost certainly be present with a butane lighter approach. (Not to mention the question of mechanics. How exactly does one hold a cent in a bar with a lighter on it long enough to bubble off the copper plating on both sides and not burn one's fingers? Go ahead, try it. I'll wait. )

A car cigarette lighter would apply heat evenly to an entire side but many of these coins show plating issues more in the center and less towards the rim.

Also, close inspection shows no signs of heat related bubbling or blistering of the plating material.

This coin displays clear evidence of split plating all around the inside of the rim which suggests some type of problem with the electroplating process.

Further, the arced disturbances under LIBERTY and on Abe's shoulder are inconsistent with the heat theory as are the small round areas on the reverse near ONE CENT.

I'm not expert enough to opine on the cause of this recurrent phenomena, but suspect this is likely related to incomplete washing of chemicals used to clean the blank prior to plating, FWIW.

I agree that this a mint made error, though a commonly found one.

This is how they electroplate the planchets. I think they don't get washed off enough before plating, that would explain how the plating wouldn't stick to the zinc.

Silviosi, Thank you for straightening me out. So this was an old way of drying out planchets? Would this be a way they were burnished? I've also read that the electroplating will build up on the edges and corners. Could this be why the center of the planchet received less plating?

Cukohn is correct.
This is the video of the plating process from the old Jarden Zinc who produces the Lincoln Cent planchets for the US mint.

Silviosi, it is not a drying system. If you look at the top of the rotating drum you can see bubbles on the surface of the liquid at the top of the screen.
I believe the title of the video refers to 45 RPM (Revolutions Per Minute) and the flexible "German Hand Grenade" like object rotating with the planchets.

From CC archives.
http://goccf.com/t/350002

Thanks Pete I went back and watched that video again. I didn't see it before, you are right you can see the air bubbles at the top. They are tumbling through the solution. Somehow they are connecting the anode and the cathode inside the drum.

Thanks for the link Silviosi. That "Dangler" is used for elotroplating aluminum blanks?
For those interested the link starts out discussing how difficult the plating process is for getting metals to adhere to aluminum. It goes on to discuss coinage being used today.

Here are a couple of selective quotes from the link:
".... The pretreatment and electroplating steps are preferably conducted by barrel plating, in accordance with another aspect of the invention.... "

This quote indicates electroplating is done by "barrel plating".

".... A particularly difficult environment for electroplated products is circulation coinage. Today, many countries of the world rely on plated coinage in which coinage metals, such as nickel, copper, bronze or brass overlayers are electroplated onto cores of coinage metals such as zinc, steel, or nickel. ..."


"Processes of electroplating such coinage cores have been developed to ensure that a highly-adherent electroplated layer is formed which can withstand a bend test. The bend test is one indication of whether the plated coinage product can withstand the rigors of a deforming process, that is a minting step, without delamination of the electroplated layers from the substrate. While bend tests may vary, in general, to pass such a test for circulation coinage, the plated coin blank is bent through a 90° angle and the plated layer must not be removable with a sharp instrument such as a file or knife. Although aluminum and its alloys have been used in coins, to the inventors' knowledge, no electroplated circulation coinage products with aluminum or aluminum alloy cores exist in the world today. Efforts by the inventors to apply a simple zincating solution, or an MAZ solution to aluminum substrates, as set out in the Examples of this application, failed to produce adequate adhesion to pass a bend test."
Interesting info about using a bend test to confirm proper adhesion of the finish metal to the substrate.






If the video isn't a demonstration of the plating process for the zinc blanks can you tell us what the video is showing?

Thanks Silviosi.

I agree the Dangler was never used at the mint. The video was from the firm that makes the Lincoln Cent planchets and ships them to the mint.

That video was originally from the old Facebook page (2016?) for Jarden Zinc. I can't remember what was mentioned about the video since the new private equity firm that bought out Jarden Zinc "cleansed" the info on the site. (The video is a hard find when searching.)