The word "sintered" has no meaning in US numismatics, except as applied to Gould private pattern pieces. There, it is part of a normal industrial practice for powdered metal technology.
The term has no application for US coinage. Some past fool liked the sound of it, and it was indiscriminately applied to completely unrelated, superficial appearance.
That any company or professional would parrot false language diminishes all.
Sintered mesh filter cartridges from stainless steel wire cloth with filter rating1-250 micron for pharmaceuticals, fluidized beds, liquid and gas filtration.
RE: "On the NGC and PCGS forms, I put the words 'Improperly Annealed Planchet.' "
That works fine. It's descriptive of the cause, which might be "fire scale" "annealing atmosphere failure" "incorrect temperature (over or under)" and others including "burnt in household fire."
If it was sintered, that would imply that the planchet has a coating of another metal and during the annealing process that layer diffused into the planchets surface and bonded.
A more likely explanation is that due to equipment issues during annealing, variations in time or atmosphere allowed copper migration to the surface of the 75Cu25Ni alloy planchet. This makes a lot more sense, since I would not expect to find much (if any) concentrations of fine Copper particles inside the annealing oven.
@RogerB said:
RE: "On the NGC and PCGS forms, I put the words 'Improperly Annealed Planchet.' "
That works fine. It's descriptive of the cause, which might be "fire scale" "annealing atmosphere failure" "incorrect temperature (over or under)" and others.
What exactly is going on because copper is being adhered to the nickel?
What the metallurgical term for what is happening?
RogerB is right. I understand that 'sintered' has come to have some meaning in numismatics, but it is entirely unrelated to its actual, technical meaning.
It's especially confusing, because sintering is a metallurgical process - it's just not part of any US Mint process. Ever.
Here, however, is a sintered medal (photo borrowed from eBay, as my example is at my office):
Now it would be interesting to hear what they mean by their use of the term.
“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.
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Last week I talked with an engineer at the Paccar shareholder's meeting (they make Kenworth and Peterbilt trucks), they had a piston prototype made from additive manufacturing by sintering powdered metal. It is a fast method of prototyping, but generally not cost-effective for production as the powdered metal Is five times the cost of stock plate. It can be used for complex shapes of expensive industrial metal such as titanium, as the "additive" process uses less metal than a "subtractive" process as in extensive machining.
"Firescale" can turn sterling or coin silver alloys black, unless flux is used prior to annealing or a sealed container is used, and a pickling (acid) solution after annealing. Sometimes "mill scale" is used for steel or Invar, an oxide produced during hot rolling and can be ground or machined off. For copper and silver alloys, I believe firescale is the correct industry term.
Roger is right.
Robert Scot: Engraving Liberty - biography of US Mint's first chief engraver
No US coins have ever been struck on planchets that were made from fused powdered metal.
However, it is probable that on a few occasions planchets were inadvertently coated with powdered metal and then annealed and struck. It would not be entirely incorrect to apply the term "sintered" to those particulate coins.
I was always under the impression that fire scale is due to oxidation of the metal at higher temps. Is the "sintered" coating due to metal migration in the alloy, or oxidation of the surfaces?
Sintering is the process of compacting and forming a solid mass of material by heat or pressure without melting it to the point of liquefaction. The term has been totally misapplied in numismatics under the false belief that it meant the discoloration was due to heating. There are no U.S. Mint coins that are sintered... as @RogerB has stated. Cheers, RickO
A further reason for objections. One day, the US Mint might use powdered metal technology for certain coins - such as a $5 piece made from titanium with an anodized surface. Such a coin would accurately be described as "sintered" because that was part of the planchet manufacturing process. Imagine the unnecessary confusion and opportunity for fraud....
@ricko said: "Sintering is the process of compacting and forming a solid mass of material by heat or pressure without melting it to the point of liquefaction. The term has been totally misapplied in numismatics under the false belief that it meant the discoloration was due to heating. There are no U.S. Mint coins that are sintered... as @RogerB has stated."
@RogerB said: "The word "sintered" has no meaning in US numismatics, except as applied to Gould private pattern pieces. There, it is part of a normal industrial practice for powdered metal technology."
You must be hiding under a rock as this term has been in the numismatic lexicon for years. There are many cases in all fields of endeavor where words are used incorrectly to describe something see that has no relationship to the true definition of the word. This is one of them. I was told it described the off-colored film-like appearance on the surface of some coins that happened during the preparation of a planchet. Whether true or not, the word has been used and accepted to describe this unusual characteristic (see slabs above). Words mean something. Unfortunately, "sintered" has taken on a false meaning. Your post may be the beginning of a necessary correction.
That said I disagree with you for now:
"Sintered" does have a long-held meaning in numismatics although flawed. So does "DOUBLE-die."
There are many words that have no actual meaning in U.S. numismatics to the majority of folks yet they are used. "Spider-web" is the first that comes to mind. "Mud-cracks" is another.
@RogerB said:
A further reason for objections. One day, the US Mint might use powdered metal technology for certain coins - such as a $5 piece made from titanium with an anodized surface. Such a coin would accurately be described as "sintered" because that was part of the planchet manufacturing process. Imagine the unnecessary confusion and opportunity for fraud....
LOL, opportunities for fraud abound for the uninformed. If someone tells an ignorant collector in the future that his dark Sac dollar is made from sintered titanium with an anodized surface, no one can stop them.
the post by RickO describes the process of "sintering" and Roger's assertion is correct. when I first started my Machining career in the early 1970's we used Compressed Powdered Metal bar stock in some applications so I am somewhat familiar with the terminology. PCGS and NGC should probably not use a specific word just because it describes how something looks but that is done often by probably all of us. hopefully, they will stop.
@Insider2... Sintered is the past tense of sintering... it is a process, it is not a 'color'....The term is incorrectly used, and no matter how long it has been used, it is wrong. You are certainly entitled to disagree, but arguing from a false position is not justification. Cheers, RickO
I was involved with the sintering processes for 25 years. The description on the slabs is not correct. As far as I know the planchets are produced by rolling and annealing
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@ricko said: @Insider2... Sintered is the past tense of sintering... it is a process, it is not a 'color'....The term is incorrectly used, and no matter how long it has been used, it is wrong. You are certainly entitled to disagree, but arguing from a false position is not justification. Cheers, RickO
I'm on your side! No one is arguing. The term is incorrect! However, I stand by the REASONS I disagreed with Roger's post. It is going to take time for that to be corrected. Until that happens, you guys will need to live with the improper use of the word as applied to discolored coins.
Finally - to be completely clear, copper dust on a planchet during annealing does not make it "sintered." It is merely superficial oxide commonly called "fire scale."
RogerB
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I’ll take your word for it. I wasn’t there.
@ErrorsOnCoins would probably buy any off-sintered ones.
PCGS has slabbed a lot of coins as having a sintered planchet so they may disagree.
I think Fred got that memo
The word "sintered" has no meaning in US numismatics, except as applied to Gould private pattern pieces. There, it is part of a normal industrial practice for powdered metal technology.
Seems like it’s a common term in “US numismatics” given the above.
I’m curious to hear what @FredWeinberg says.
The term has no application for US coinage. Some past fool liked the sound of it, and it was indiscriminately applied to completely unrelated, superficial appearance.
That any company or professional would parrot false language diminishes all.
Sintered mesh filter cartridges from stainless steel wire cloth with filter rating1-250 micron for pharmaceuticals, fluidized beds, liquid and gas filtration.
On the NGC and PCGS forms, I put the words "Improperly Annealed Planchet"
NGC still uses "sintered" while I believe Fred now uses Improperly Annealed Planchet.
RE: "On the NGC and PCGS forms, I put the words 'Improperly Annealed Planchet.' "
That works fine. It's descriptive of the cause, which might be "fire scale" "annealing atmosphere failure" "incorrect temperature (over or under)" and others including "burnt in household fire."
If it was sintered, that would imply that the planchet has a coating of another metal and during the annealing process that layer diffused into the planchets surface and bonded.
A more likely explanation is that due to equipment issues during annealing, variations in time or atmosphere allowed copper migration to the surface of the 75Cu25Ni alloy planchet. This makes a lot more sense, since I would not expect to find much (if any) concentrations of fine Copper particles inside the annealing oven.
What exactly is going on because copper is being adhered to the nickel?
What the metallurgical term for what is happening?
It is not heat toning.
The Mint and industry term for surface contamination and oxidation of copper is "fire scale." It has multiple causes.
Sintering is an intentional manufacturing process. No US coin was ever "sintered."
Googling "fire scale" bring up jewelry issues, googling "fire scale coins" bring up almost nothing.
A coin in house fire coin definitely looks different than what I have above which are considered error coins.
I do not want to argue with you.
I will go with what the TPS say instead of one opinion on the internet, even tho I respect your opinions greatly.
I do not think this subject matters all that much to most people, I mean the terminology issue that you have that is.
Peace out.
RogerB is right. I understand that 'sintered' has come to have some meaning in numismatics, but it is entirely unrelated to its actual, technical meaning.
It's especially confusing, because sintering is a metallurgical process - it's just not part of any US Mint process. Ever.
Here, however, is a sintered medal (photo borrowed from eBay, as my example is at my office):
Oh, goodie, I get to say it...
Just because a TPG says it, doesn't make it true.
Now it would be interesting to hear what they mean by their use of the term.
“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.
ANA 50 year/Life Member (now "Emeritus")
By the way, sintering is not a bad thing. It is a way to make metal objects from powdered metal.
That makes it all the more confusing why it is used to describe a problem with a coin.
Last week I talked with an engineer at the Paccar shareholder's meeting (they make Kenworth and Peterbilt trucks), they had a piston prototype made from additive manufacturing by sintering powdered metal. It is a fast method of prototyping, but generally not cost-effective for production as the powdered metal Is five times the cost of stock plate. It can be used for complex shapes of expensive industrial metal such as titanium, as the "additive" process uses less metal than a "subtractive" process as in extensive machining.
"Firescale" can turn sterling or coin silver alloys black, unless flux is used prior to annealing or a sealed container is used, and a pickling (acid) solution after annealing. Sometimes "mill scale" is used for steel or Invar, an oxide produced during hot rolling and can be ground or machined off. For copper and silver alloys, I believe firescale is the correct industry term.
Roger is right.
No US coins have ever been struck on planchets that were made from fused powdered metal.
However, it is probable that on a few occasions planchets were inadvertently coated with powdered metal and then annealed and struck. It would not be entirely incorrect to apply the term "sintered" to those particulate coins.
I was always under the impression that fire scale is due to oxidation of the metal at higher temps. Is the "sintered" coating due to metal migration in the alloy, or oxidation of the surfaces?
Many sinter processes do not involve powdered metals.
One section of manufacturing I ran for years involved sintering filmed and etched aluminum.
Sintering is the process of compacting and forming a solid mass of material by heat or pressure without melting it to the point of liquefaction. The term has been totally misapplied in numismatics under the false belief that it meant the discoloration was due to heating. There are no U.S. Mint coins that are sintered... as @RogerB has stated. Cheers, RickO
Tell me when PCGS and NGC will fix the "mechanical errors" on the labels for free including shipping and I will send them in
The language used by ErrorsonCoins and Fred Weinberg is reasonable and fully applicable to numismatic coins.
Here is a private pattern piece made from sintered powder metal. It has no visible similarity to coins labeled "sintered."
A further reason for objections. One day, the US Mint might use powdered metal technology for certain coins - such as a $5 piece made from titanium with an anodized surface. Such a coin would accurately be described as "sintered" because that was part of the planchet manufacturing process. Imagine the unnecessary confusion and opportunity for fraud....
@ricko said: "Sintering is the process of compacting and forming a solid mass of material by heat or pressure without melting it to the point of liquefaction. The term has been totally misapplied in numismatics under the false belief that it meant the discoloration was due to heating. There are no U.S. Mint coins that are sintered... as @RogerB has stated."
@RogerB said: "The word "sintered" has no meaning in US numismatics, except as applied to Gould private pattern pieces. There, it is part of a normal industrial practice for powdered metal technology."
You must be hiding under a rock as this term has been in the numismatic lexicon for years. There are many cases in all fields of endeavor where words are used incorrectly to describe something see that has no relationship to the true definition of the word. This is one of them. I was told it described the off-colored film-like appearance on the surface of some coins that happened during the preparation of a planchet. Whether true or not, the word has been used and accepted to describe this unusual characteristic (see slabs above). Words mean something. Unfortunately, "sintered" has taken on a false meaning. Your post may be the beginning of a necessary correction.
That said I disagree with you for now:
LOL, opportunities for fraud abound for the uninformed. If someone tells an ignorant collector in the future that his dark Sac dollar is made from sintered titanium with an anodized surface, no one can stop them.
What happens if I say "sintered penny"?
the post by RickO describes the process of "sintering" and Roger's assertion is correct. when I first started my Machining career in the early 1970's we used Compressed Powdered Metal bar stock in some applications so I am somewhat familiar with the terminology. PCGS and NGC should probably not use a specific word just because it describes how something looks but that is done often by probably all of us. hopefully, they will stop.
@Insider2... Sintered is the past tense of sintering... it is a process, it is not a 'color'....The term is incorrectly used, and no matter how long it has been used, it is wrong. You are certainly entitled to disagree, but arguing from a false position is not justification. Cheers, RickO
Reminds me of lamination or de-lamination designations.
I was involved with the sintering processes for 25 years. The description on the slabs is not correct. As far as I know the planchets are produced by rolling and annealing
"A dog breaks your heart only one time and that is when they pass on". Unknown
all of my coins are centered.
"Paper is poverty … it is only the ghost of money, and not money itself.” - Thomas Jefferson
Just photographed the new coin in ....
I'm on your side! No one is arguing. The term is incorrect! However, I stand by the REASONS I disagreed with Roger's post. It is going to take time for that to be corrected. Until that happens, you guys will need to live with the improper use of the word as applied to discolored coins.
@Insider2 ...."you guys" includes YOU....
Cheers, RickO
Finally - to be completely clear, copper dust on a planchet during annealing does not make it "sintered." It is merely superficial oxide commonly called "fire scale."
Not so fast...we changed the terminology on our labels almost a year ago.