I saw that report show up on one of my searches, but didn't see anything in the title that would warrant searching through 200+ pages. Thanks for doing the heavy lifting.
NP Just opened it, clicked in the TOC on the background section and it was half a page in. It was a decent bet to check knowing that the purpose of the study was alternate materials for the cent and nickel.
One of the keys is the corrosion inhibitor the mint started using. Also, the planchet manufacturing process, minting process and metal purities probably improved over the years too. Of course, age comes into play as well. Cents see very hard duty in circulation!
Close! It's not plastic or epoxy, it's a chemical corrosion inhibitor. The copper is not "1 molecule thick", the corrosion inhibitor is.
What is this mystery molecule? When is it applied to the coin? How is it applied to the coin? How long does it stay on the typical circulating coin? All BS until those questions can be answered without invoking additional questions.
There are many different types of corrosion inhibitors. I don't think the mint or supplier is going to publish their process. Why tell others what may be a competitive advantage. It makes sense to use a corrosion inhibitor, and it probably took a lot of R&D and experimentation to find one that meets the requirements for coinage. My guess is that it is used to keep the planchets from being damaged during transportation and storage prior to striking and not provide much protection post minting. I would expect that this wear off at some point early in circulation, if it even survives the minting process. I think the mystery molecule is going to remain a mystery unless someone who has worked in the metal industry and isn't bound by non-disclosure agreement is a member of CT. Until then, you're stuck with some educated guesses from people with chemical and manufacturing backgrounds that may have validity. The nice thing about this list is that there is enough background knowledge for members to challenge statements without resorting to a blanket "That's BS" statement. I've only been on this list since the beginning of the year but it's readily apparent which list members know something and which are full of................ Maybe a better question should have been something like "How do corrosion inhibitors work" or "Wouldn't they wear off in circulation" rather than "Prove it or it's BS"
Often times clues are in the mint's videos of the coin production process. If they show something being added to the blanks during the pre-strike polishing process and not being rinsed off... the only one I can find is general circulating coins, but they do show the cent blanks running through the upsetting mill at the mint.
The BEST "corrosion inhibitor" is to keep all Zincolns free from physical damage and low pH liquids. Zinc and copper are highly reactive in an acid environment. Even a tiny pin prick sized hole through the 8 micron copper layer sets environmental damage in motion. Even most tap water is on the acidic side. Keep in mind that the mint does not press cent blanks. They buy them pre-blanked and they occasionally "decorate" I-95. http://www.ksdk.com/traffic/interstate-non-cents-unstamped-coins-spill-in-delaware/315575635
Any corrosion inhibitor needs to be between the copper and zinc to prevent galvanic corrosion. A "coating" on the coin may prevent an external catalyst from accelerating the corrosion until it wears off, but does not change the fact that copper in contact with zinc is unstable.
Gee, I thought it was "Kurt shows up late with opinions" And that would be part of the vendor's proprietary process, of which we have no specifications. The USM video shows them being washed in some solution before being fed into the upsetting machine. That could have the (mythical?) protective layer. Or it could just be soapy water.
So this little corgi read both of these statements quoted below. Both offered as "fact" and neither statement backed up with references. Am I to believe both or should I believe Thad or should I believe lehman? I don't know either of them from a hole in the ground. My only recourse is to disbelieve both (i.e. call them both BS) until references are provided. Take that and smoke it in your pipe.
Gimme a break! I just got in from my ANA trip late last night. Stopped in Chicago to hang out with the Chicago Coin Club guys.
If you read through the posts, the logical conclusion is that Thad's is the correct info. Lehman's info was called out as being questionable on at least 3 posts. prior to Thad's comment. In addition, reading the comments about corrosion inhibitors, manufacturing processes, and proprietary information, also point to Thad's being correct. You could have also done some side research on corrosion inhibitors to get a better understanding (that's what I did). As stated previously, we may never know what chemical is used or even if it was ever used, but putting the pieces together in this thread makes a good case for a corrosion inhibitor. I don't understand the math behind Quantum Mechanics, but I don't call out the Physicists if they can't give me 100% proof.
That reminds me of when I was in the election administration game and I was on election discussion boards, and people would ask, "What's your source?" My source was "me", I lived it. I didn't need some jabronie to write about it, and get the details all wrong, as they usually did, and put it on a website before I knew truth that I lived. Object lesson: virtually EVERYTHING you've ever read in MSM about the conduct of an election is WRONG in very important ways. "Truth doesn't need a source and hundreds of sources can't verify a falsehood."
I dun thinked it up all by my bad seff. But there IS this: “The truth will set you free, but first it will piss you off.” ― Joe Klaas, Twelve Steps to Happiness and this: “Men occasionally stumble over the truth, but most of them pick themselves up and hurry off as if nothing ever happened.” ― Winston S. Churchill
But the galvanic corrosion requires water in order to proceed, so any inhibitor that keeps water away from the Cu/Zn juction witll stop that form of corrosion, In fact as long as there are no holes in the copper layer to let water in the corrosion will not occur either.
Indeed!!! Most people are scared to death of the truth and find it best to not even try to recognize it.