I think I have a improper alloy mix 1980p penny error

@Insider I think the lamination is a red herring for the following reasons.

The lamination cuts perpendicular across the discolored areas. I would expect that the lamination would follow the boundaries of the poorly mixed regions. If the regions have different ductility or hardness due to composition variation, they may not bond well as the ingot is rolled and elongated. This could result in weakness or lack of bonding between the regions along the boundaries. No issues there. But the lamination on this coin crosses multiple discolored regions. That doesn't make sense. And if the regions have a similar hardness, then they would be bonded with the other metal grains, so there wouldn't be a lamination.

If the lamination is caused by a gas bubble or void, once again, I wouldn't expect it to cross through regions of differing compositions. Some reasons for poor mixing may be due to an area being hotter or colder than the bulk material. This could result in different viscosities within the melt. Also, It would not be unusual for regions of differing compositions to have different viscosities as they melt. How would a bubble cut across regions that have varying viscosities? It can't. The bubble would stay in the most fluid region

Now if the marks were just stains left by a dirty roller and toned at different rates over the years, a lamination could easily cut across them because it was already in the ingot before rolling.

I'm not a metallurgist and don't claim the comments in my last 2 posts offer definitive proof, but IMO, there are too many things that don't line up to make me believe it's an improperly mixed alloy. I believe the discoloration is a stain left by dirty rollers.

 

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Laminations usually line up where the different metals meet. In this case it does not. Nevertheless, since they are very common on ally mix errors and at least one knowledgeable error expert had not seen one associated with dirty rollers...I think the weight of the characteristic falls onto my side of the balance.

Additionally, on the OP's coin, the colors are both shades seen on bronze mixes. There is no hint of impressed dirty debris.

 

Slight variability in the width of the stripes on the OP's coin are of no relevance, and the small lamination flap on Kentucky's coin is simply a distraction. To repeat, the key indicators that coins like these are not improper alloy mix errors are the superficial nature of the stripes (easily worn through) and the failure of any cracking to develop parallel to the straight lines. Now, the roller hypothesis may eventually be proven incorrect as there may be some other source of parallel lines on planchets that I'm not aware of. But in the absence of any other hypothesis, I'm sticking with it. Perhaps the heat generated during rolling "bakes in" some form of discoloration derived from the rollers. Anyway, here is some more information on stripes on coins: https://www.coinworld.com/news/prec...tripes-on-coins-are-not-fully-understood.html This topic has grown tiresome, so I will no longer be contributing to it.

 

mikediamond, posted: "This topic has grown tiresome, so I will no longer be contributing to it."

I hope I'm replying for many of us here: Sorry to read this, thanks for your opinion.

 

Just to clarify, not my coin. Reposted a picture from the OP...#23

 

What I'm reading in your post says that since lamination s are common in improperly alloyed metals and since there is a lamination on the OPs coin, it must be improperly mixed. And your supporting information is that an error expert has never seen a lamination on a roller marked coin? And the weight of that information is enough to tip the conclusions towards your side of the discussion? Is that correct, or did I miss something?

C'mon. At least I tried to back up my comments with some science and chemistry

I don't understand why a coin with roller marks couldn't also have a lamination. The mechanism for the formation of laminations occurs during the ingot casting process. Entrapped gas or poorly mixed alloys. Wouldn't this be independent of the rolling process?

Also, Could you please offer an explanation/hypothesis on how a lamination can cut across grain boundaries of dissimilar compositions yet show no evidence of following the grain boundary? It doesn't make sense for an unbonded area to be intragranular when the grain boundaries of dissimilar compositions would likely be the weakest point. And if the grain boundaries are strong enough so that the unbonded area is intragranular, how did the void that initiated the lamination form in the first place?

 

Oldhoopster, posted: "What I'm reading in your post says that since lamination s are common in improperly alloyed metals and since there is a lamination on the OPs coin, it must be improperly mixed. [ Not at all. What I said was since they are very common on alloy mix errors and 1-in-a-million (so they could possibly happen) associated with a roller mark (I don't recall ever seeing this) then the evidence on the coin SHOULD SUPPORT my opinion.] And your supporting information is that an error expert has never seen a lamination on a roller marked coin? [Yes, that's both the expert and me] And the weight of that information [Combined with everything else I see on the coin] is enough to tip the conclusions towards your side of the discussion? Is that correct, or did I miss something?" I think you get it. Now, I need to be refuted or agreed with. I want my questions answered.

"C'mon. At least I tried to back up my comments with some science and chemistry."

"I don't understand why a coin with roller marks couldn't also have a lamination. [I don't either. Any coin or mint error can have a lamination caused by multiple reasons.] The mechanism for the formation of laminations occurs during the ingot casting process. Entrapped gas or poorly mixed alloys. Wouldn't this be independent of the rolling process?" [I don't think so. While making the strip, gas and impurities that cause laminations my be removed and impurities may also be added.]

"Also, Could you please offer an explanation/hypothesis on how a lamination can cut across grain boundaries of dissimilar compositions yet show no evidence of following the grain boundary? [I've been looking for images in my computer files that will support my opinion and blow folks mind! I have a day job too. I just made an image of a streaked cent edge showing how deep the improper alloy goes into the coin! Cannot find it yet.] It doesn't make sense for an unbonded area to be intragranular when the grain boundaries of dissimilar compositions would likely be the weakest point. And if the grain boundaries are strong enough so that the unbonded area is intragranular, how did the void that initiated the lamination form in the first place?" [LOL, I have found that things happen all the time that don't make sense. Therefore, my opinion still stands for now. I'll need to give it some thought.]

 

I agree that laminations can occur in improperly mixed alloys, but they can also be caused by gas bubbles/voids that are unrelated to poorly mixed allows. In the glass industry, seeds (partially melted raw materials) and blisters (gas bubbles) are common defects. Depending on the root cause, they may be related or form independently. Although I’m not a metallurgist, I would expect similarities between a glass melt and metal melt.

You keep saying “I want my questions answered”. I tried to provide answers to your question about the characteristics that led me to conclude that this can’t be an improperly mixed alloy, yet you asked it again. Do you disagree with my explanation that debonding would likely occur along grain boundaries of improperly mixed regions and not cut through differing regions due to ductility/hardness variations? Do you disagree that varying compositional regions in the melt (or partial melt) may have different viscosities and that it would be unlikely that a gas bubble would cut through these regions and not stay in the lower viscosity region? I’m not saying those explanations are correct, but the make a lot of sense to someone who has spent nearly 30 years working in the Glass/Ceramic field.

I believe I provided a reasonable explanation based on science and will be waiting for your pictures showing laminations cutting through regions of varying compositions while avoiding the grain boundaries. I hope you find your pics, because try as I might, I can’t think of any material science or chemistry explanations that support this. I know there are some chemists and metallurgists on this site and would be interested in their feedback regarding my comments, and am always willing to listen to alternate theories. That's how we learn

 

Oldhoopster, posted: "I agree that laminations can occur in improperly mixed alloys, but they can also be caused by gas bubbles/voids that are unrelated to poorly mixed allows. [ You are making me respond to the obvious! I already posted above that a lamination can occur on any coin!] In the glass industry, seeds (partially melted raw materials) and blisters (gas bubbles) are common defects. Depending on the root cause, they may be related or form independently. Although I’m not a metallurgist, I would expect similarities between a glass melt and metal melt. [So you are an expert in glass melts but not in metallurgy yet we are going to discuss what you EXPECT? No thanks.]

You keep saying “I want my questions answered”. I tried to provide answers to your question about the characteristics that led me to conclude that this can’t be an improperly mixed alloy, yet you asked it again. Do you disagree with my explanation that debonding would likely occur along grain boundaries of improperly mixed regions and not cut through differing regions due to ductility/hardness variations? [I agree with this; however, I EXPECT (LOL) that the other case is possible and probably rare.] Do you disagree that varying compositional regions in the melt (or partial melt) may have different viscosities and that it would be unlikely that a gas bubble would cut through these regions and not stay in the lower viscosity region? [I agree with this. Technicians at the Mint told us that Hydrogen gas can get trapped in the strip. Since it is smaller than the other atoms in the alloy, it will EVENTUALLY migrate to the surface of a struck coin causing laminations. Heat adds this migration.] I’m not saying those explanations are correct, but the make a lot of sense to someone who has spent nearly 30 years working in the Glass/Ceramic field."

"I believe I provided a reasonable explanation based on science and will be waiting for your pictures showing laminations cutting through regions of varying compositions while avoiding the grain boundaries. I hope you find your pics, because try as I might, I can’t think of any material science or chemistry explanations that support this. I know there are some chemists and metallurgists on this site and would be interested in their feedback regarding my comments, and am always willing to listen to alternate theories. That's how we learn."

I agree; however I am not going to let you sidetrack this discussion until it is finished. We are discussing the OP's coin and how the streaks were formed. It happens to have a lamination. Laminations have NOTHING TO DO WITH ROLLER MARKS. LAMINATIONS ARE ASSOCIATED WITH ALLOY ERRORS!

It's too bad the error experts have ducked out of this discussion. I'm curious as to how all the cents shown with bi-color "dirty roller marks" have their incuse lines from the rollers (on the planchet in two colors ) completely struck out on the finished coin. I'm also curious why the OP's coin has streaks of different widths while the streaks on what they call "roller error coins" are uniform.

 

Although lamentations are associated with improper mixing, they can also occur due to gas bubbles and both are independent events. How many laminations are due to mixing and how many are due to gas bubbles? Don't know, but in glass melts, bubbles are more common than unmixed, partially melted material. Is this different for metals? Maybe, but I would be surprised if it was significantly different.

This is my explanation of why I believe it cannot be poorly mixed and I've offered some science that can be checked. I was hoping that any discussion would involve something more than anecdotal observations and general statements saying "laminations are found in poorly mixed metals, this coin has laminations, therefore it must be a poorly mixed alloy". While those types of observations can be valuable, when they don't support some of the basic science explanations, I have to question them.

I don't have a solid explanation of the dirty roller theory and I have stated that previously. I do believe it's possible for oil/lubrication to be pressed into the surface at shallow depths (I believe @mikediamond proposed something like this) and then tone/stain over time, but can offer no hard facts or proof.

I guess we will have to agree to disagree. The theories/explanations are posted for others to read, question, and draw their own conclusions. Thanks for the discussion. I had originally glossed over this thread, but your comments got me thinking about it.

 

Oldhoopster, posted: "Although lamentations are associated with improper mixing, they can also occur due to gas bubbles and both are independent events. [You are repeating things already discussed that we both agree on.] How many laminations are due to mixing and how many are due to gas bubbles? Don't know, but in glass melts, bubbles are more common than unmixed, partially melted material. Is this different for metals? Maybe, but I would be surprised if it was significantly different."

This is my explanation of why I believe it cannot be poorly mixed and I've offered some science that can be checked. I was hoping that any discussion would involve something more than anecdotal observations and general statements saying "laminations are found in poorly mixed metals, this coin has laminations, therefore it must be a poorly mixed alloy". [ That was not said. What was said was laminations are associated with alloy errors and not roller marks. The lamination is less important than the other characteristics of the OP's coin.] While those types of observations can be valuable, when they don't support some of the basic science explanations, I have to question them.

I don't have a solid explanation of the dirty roller theory and I have stated that previously. I do believe it's possible for oil/lubrication to be pressed into the surface at shallow depths (I believe @mikediamond proposed something like this) and then tone/stain over time, [ditto. I never heard of dirty roller streaks until this thread. I wish to learn more at another time.] but can offer no hard facts or proof.

I guess we will have to agree to disagree. The theories/explanations are posted for others to read, question, and draw their own conclusions. Thanks for the discussion. I had originally glossed over this thread, but your comments got me thinking about it. [Me also.]

 

I'm not a metallurgist either, I am an organic chemist. However the similarity and differences between metals and glasses I think has to do with crystallinity. I know glass can crystallize, but usually exists as an amorphous solid. In metals I think crystals are more the rule than the exception. In a mixture of two metals, we don't only have the two separate metals, but we have a myriad of phases of the two depending on the mixing. Boundary separation doesn't have to occur only on the surface, but can occur below the surface with an accompanying rupture of the surface, so a lamination might not show a surface feature, but could be associated with alloys rather than pure materials. As far as the OP coin, it looks like a woodie to me, but I will admit the possibility that it isn't.

 

I have ducked out the discussion because you are flat out wrong and I have not learned a single thing from you about this discussion.

I would advise you, as a friend, to stick to non-errors. I am curious as to why someone -who even admits he really doesn't know errors all that well - continues to belabor points that are contrary to scientific analysis.

In addition, and what is most absurd, is a persistent effort to deny and exclude comparisons of photos of similar coins, and then engages in infantile hissy-fits at the mere suggestion to examine them.

Show me any serious scientist who insists comparative examples must be ignored.

It is at the point where I can no longer take you seriously, especially seeing that so many damaged coins have been certified by ICG as genuine errors. In particular, brockages that are unquestionably vise jobs and chemically-altered cents missing copper plating.

If you want help at ICG, which is sorely needed, please consider my offer.

 

You can never have enough books. The chinese youst to roll their sacred scrolls.

 

JCro57, posted: "I have ducked out the discussion because you are flat out wrong and I have not learned a single thing from you about this discussion.

I would advise you, as a friend, to stick to non-errors. I am curious as to why someone -who even admits he really doesn't know errors all that well - continues to belabor points that are contrary to scientific analysis.

In addition, and what is most absurd, is a persistent effort to deny and exclude comparisons of photos of similar coins, and then engages in infantile hissy-fits at the mere suggestion to examine them.

Show me any serious scientist who insists comparative examples must be ignored.

It is at the point where I can no longer take you seriously, especially seeing that so many damaged coins have been certified by ICG as genuine errors. In particular, brockages that are unquestionably vise jobs and chemically-altered cents missing copper plating.

If you want help at ICG, which is sorely needed, please consider my offer."

The coins being called "dirty roller error coins" may look identical to an "expert" but a simple examination by a non-numismatist with a "good-eye-for-detail" will note that the OP's coin seems to show two different colors of common bronze w/o the dark streaks (on the other coins) that have been said to be caused by dirty rollers.

I have a completely open mind. Decades ago, there was no such thing as a coin struck with dirty rollers. As I wrote before, the coins you posted are the first "modern" coins I've ever seen with dark streaks. Apparently new generations of error collectors have decided ALL OF THEM have the same cause. So far, it makes sense but as I posted, IMO, those coins are different from the OP's.

As to this... Talk is cheap. "I can no longer take you seriously, especially seeing that so many damaged coins have been certified by ICG as genuine errors. In particular, brockages that are unquestionably vise jobs and chemically-altered cents missing copper plating."

PS I'll look forward to reading your new book. Hopefully, it will have some new information not seen in the error books published previously.

 

Well, at least I appreciate the fact you can take it when you dish it out. I respect that very much actually. (No joking)

I am sending you some coins to encapsulate as known fakes/altered coins with the yellow label. They make great teaching tools, and I have been pleased with how my others came back from ICG with the "Counterfeit" tag on them.

As for my book, I do offer a few alternative theories on things. For example, I stand by that machine doubling is a Mint Error, that there needs to be a distinct difference between altered and counterfeit (among others), what "damaged" should mean and not mean, and etc.

 

JCro57, posted: "Well, at least I appreciate the fact you can take it when you dish it out. I respect that very much actually. (No joking)

I am sending you some coins to encapsulate as known fakes/altered coins with the yellow label. They make great teaching tools, and I have been pleased with how my others came back from ICG with the "Counterfeit" tag on them.

As for my book, I do offer a few alternative theories on things. For example, I stand by that machine doubling is a Mint Error, that there needs to be a distinct difference between altered and counterfeit (among others), what "damaged" should mean and not mean, and etc."

Whenever intelligent folks communicate by any method on any subject without animus they each should be able to dish it out to make their point.

PS Unlike others, I'm willing to "battle-it-out" to reach a conclusion - either changing my opinion or theirs. The correct answer is important.