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Question about cast counterfeits…
MrEureka
Posts: 24,812 ✭✭✭✭✭
Theoretically, could a pair of authentic dies be used to form a mold for cast fakes?
Andy Lustig
Doggedly collecting coins of the Central American Republic.
Visit the Society of US Pattern Collectors at USPatterns.com.
Doggedly collecting coins of the Central American Republic.
Visit the Society of US Pattern Collectors at USPatterns.com.
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No, because there would be nothing to shape the edge. The molten metal would just run out.
I would think so. The problem is you have to get medal flow (mint luster) and avoid bubbles. If you are going for a “circulated fake,” it gets easier. That’s why some of the fakes that have made it into legitimate slabs have been “details” grade. The counterfeiter can scrape off the surface problems and call it “improper cleaning.”
The dies could be incorporated into a mold. I’m wondering more along the lines of how molten metal would react with the dies, separate from the dies once cooled, etc.
Doggedly collecting coins of the Central American Republic.
Visit the Society of US Pattern Collectors at USPatterns.com.
It seems to me that people who make cast counterfeits are people who are not sophisticated enough to make usable dies. If you have usable dies, why not just strike coins from them?
This is an engineering problem. I'm a chemist, not an engineer, so take this answer with the proverbial grain of sodium chloride.
I'd reckon coin dies are too unwieldy to use to make a coin mould from. They're big, heavy chunks of hardened steel. A casting mould is normally made from clay, plasticine or plaster.
Can it be done in theory? Yes, I suppose, though the dies would need to be extensively modified to make them work in a die casting process.
Yes, molten metal will tend to stick to the die, though how much this occurs would likely depend on the alloy being used. Die casting uses a lubricant to make sure the molten metal does not directly come in contact with the die, making the technique not very suitable for creating die-cast objects with fine details (like a coin). The end result of such an attempt would probably create an overall "mushy" appearance, not unlike the entire coin being "grease filled".
All the websites discussing die casting talk about making objects from aluminium, zinc, magnesium, brass and bronze - not silver. Probably because silver is probably more suited to regular casting, and probably also because die casting tends to be quite wasteful, and is more suitable to bulk operations.
TLDR: yes, in theory you can put in a lot of effort to make it work. But if you've got the industrial kit to do all that, you've probably also got the kit to simply use the dies as regular coinage dies, and get a higher quality fake coin as a result.
Roman emperor Marcus Aurelius, "Meditations"
Apparently I have been awarded the DPOTD twice.
In my medal and jewelry casting experience, I would say dies could be used to make decent molten wax casting and then use those wax models in a lost wax investment type casting process. Small amounts of shrinkage can occur depending on materials +- .05% possibly overcome with varying resins. Likely not resulting a passable mint state coin to a seasoned collector, but a casting with added finish work may pass as a circulated piece, depending on expertise.
I use A2 tool steel for my dies.
In virgin (as forged) form, it is about 20 on the hardness scale when I engrave it.
After engraving and then heat-treating (hardening) it is about 60 on the hardness scale.
I also use hardened A2 steel for my ingot molds (for pouring copper and silver bars).
The molten metal does not stick to the mold. However, the thermal mass of dies would quickly draw heat out of the molten metal and it would likely start to solidify before the narrow void between the dies is completely filled.
If a person had dies, it would probably be a lot easier to strike with the dies rather than trying to make a mold out of them.
There are opinions here more expert than mine but it would seem that there are at least several possible methods for achieving this.
Copying the die using a lathe and making models from which molds could be produced might be another method. You could then make the mold out of any material that you might want.
Are you using the dies as 2 sides of a mold or to make a mold for casting fakes? The dies themselves have the wrong relief for molds and would not work as well as a coin. If you had the dies, why wouldn't you use them to strike a planchet and get the luster?
Don’t know about your cast fakes just want to say thank you for your cool store card. I’ve always liked the Costa Rica Reales gold. Owned a couple in the past.
I was gushing over it, I love that coin/card!
chopmarkedtradedollars.com
Don"t forget about shrinkage and loss of detail, J.P.
62 yrs in Coins, 42 yrs Certifying/Grading, CoinWorld's Most Influential People In Numismatics, 1960-2020. 30 consecutive yrs teaching ANA Summer seminar, Numismatic Ambassador award, 1998 Doctorate in Numismatics, Glenn Smedley Award, ANA Governor 2009/2011, Author/ Host of ANA's best selling video's, courses on grading & counterfeit detection. Taught over 1,100 paying students, Secret service agents, San Diego to Boston, Anchorage to Miami, including 2 coin cruise lecturer. many Free presentations. NLG book and video awards. ANA photographer, SEM operator, ASA Appraiser, Contributor to Redbook, Numismatist, Coin World, Numismatic News, ANA Grading Guides, 40,000 Volume Library, Founder ANAAB, ICG, 1995 ANA collector services appraisal/conservation, First full service Ancient coin grading service. Navy 75-77, WIU 77-81, Dealer1981-1984, ANA 1984-1998, 60 year Collector U.S./ 50 Year Ancient coins. ANA Advisory Committee. Life member ANA, ANS. Semi-retired grader in Denver area