Zincolns..? opinion question

Someone asked a really good question the other day on a Facebook collecting site that I am part of that I would like the insight from some members here. There wasn't much response from the members but the question was "why does it seem there are so many Zincolns from 1982 -2000 that has so many problems such as zinc rot and plating issues and after 2000 it seems that there is not as much of the zinc problems, did the mint change the purity of the zinc or the composition of the coin?" I see where he's coming from because I go through many cents and you dont see as much post 2000 with plating issues and zinc rot, My personal opinion is that maybe its cause they haven't been in circulation as long but then again 2000 was 17 years ago and for those coins thats a long time.

 

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Why did my Grandmother look older than my mom? She's was older.

I have discovered the opposite. I have found Zincolns from 2000 onward that look horrible and many pre 2000 Zincolns that look pristine!

Your question is interesting though. Maybe some kind of better quality measure taken.. maybe new minting machines?

Peace

 

Usually, manufacturers are looking for continuous improvements in their processes, either for cost savings or to improve quality. The planchet supplier(s) may have been pushed for improvements by the mint over the years, and that's what you're seeing.

 

US coins are not my metier, I'm an ancients guy, but I believe that I was told by one of my more US-obsessed friends that the "Zincolns" (great name for them, I never heard it before) in addition to their microscopically thin (I've heard "1 molecule thick" but suppose that's an exaggeration) plating of copper, have a thin coating of a very tough, clear plastic polymer (something like an epoxy) as their outermost surface. It is this virtually invisible layer which actually seals the coin and keeps the zinc from oxidizing. It is very tough - tough enough to protect a lightweight coin like a zinc cent in average contact with other coins in a cash-drawer or pocket. Drop that same cent on the sidewalk cement or parking lot asphalt and step on it - or subject it to anything else that could interrupt the plastic glaze - the voids, even microscopic voids, in the plastic coating can be a source/locus of a future corroded spot or area. Anything that will introduce microscopic holes in the polymer coating can then allow the elements through. Oxygen can reach and affect the stability of the zinc core and will begin the destructive processes which proceed so quickly on zinc surfaces.

 

wow. how does this kind of info get passed around as fact?

 

1 of the CS suppliers for cent blanks: http://jardenzinc.com/products-2-2-2-2-2/

 

They may have slightly increased the thickness of the plating, different basining of the dies or slight modifying of the relief or slope of the edges of the lettering in the die could result in less frequent split plating problems. Slight changes in the shape/degree of the upsetting of the edges of the planchets can result in less outward metal movement and less stretched plating meaning fewer tiny tears/cracks in the plating.

 

There have been numerous improvements to the planchet and striking of the zincs over the years. It's been two steps forward and one step back.

Of course the biggest improvements came early on so some of the early dates are almost impossible to find nice. If you don't believe it try finding an '84 (P) that is pristine, well struck and has attractive surfaces.

 

They had a lot of trouble with the mint set coins in 1988 and '89 because the strike sheared the plating right off on the reverse lettering.

 

Uh...no

 

Zinc is crud. You might as well make coins out of aluminum foil.

 

Zinc doesn't make the best looking coinage but there's no indication that the metal itself is unsuitable for coinage. German Third Reich coins from WW2 were made from zinc and there are literally tons of them still remaining showing no to little corrosion or "rot". True, they didn't circulate much but they're still 75 years old.

 

Those Germans just know how to make stuff.

 

Zinc is much more anodic than copper, so in the presence of some sort of catalyst (humidity, sweat, etc.) you will get some nasty galvanic corrosion.

 

I have

I have never heard of a molecular plastic plating

 

And the company that makes the blanks says nothing about it. If that were one of their capabilities they woukd surely advertise it.

 

Maybe the plating is improved? I've noticed for 2016-2017 (maybe even earlier?) cents there's even proof-like strikes that are more typical than not, too; though, I'm unsure what polished dies will do to impede zinc rot in the future.

So, as others have stated, improvements in manufacturing processes and the fact that the coins will inevitably succumb to zinc rot due to mere age may be the reasons.

 

Somewhat related to the topic.

Does anyone have info on the copper thickness specs on plated planchets? I've seen numbers ranging from 8-20 microns but don't know if that's for the planchet, or struck coin (which I suspect will vary due to metal flow after striking). Although they sound reasonable, none of the values I found had any references so I would really like to know the actual thickness range

Thanks

 

Let me Google that for you...

https://www.usmint.gov/wordpress/wp-content/uploads/2016/06/2014-rd-biennial-report-appendix-4.pdf