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This is what a bad electrotype looks like
jonathanb
Posts: 3,430 ✭✭✭✭✭
I was going to send these pics to a forum member in email, but I don't think that electrotypes have discussed here recently, so I might as well post them for everyone to look at.
An electrotype is a kind of counterfeit, but not necessarily produced with intent to defraud. A lot were made in the 1800s as a way for collectors to finish their sets even when some pieces were unobtainable otherwise. They were also used by museums for the same reason.
Electrotypes are produced by electrically plating a thin layer of metal onto a real specimen. Two half-shells are made, and peeled off each side of the original. They are then joined and filled (typically with lead or solder or some low-melting filler).
The example here is particularly poor quality electrotype. Because of the way that they are made, electrotypes will have seams where the two shells are joined. I have a much-better quality electrotype where the seam is right at the "corner" where the edge of the medal meets the face, so it's hard to spot unless you're looking for it. On this medal, the seam is right down the center of the edge. Also it appears that only the reverse shell got an impression of the original reeding. The seam is more or less visible around the whole circumference of the medal, but it's super-duper obvious where a rim ding caused it to separate even further.
This example also shows significant bulging of the obverse toward the upper right quadrant (the horse's head and surrounding area). This happened when the filling material wasn't flat between the shells.
On low-grade electrotypes, the shells may wear through to show the filling material, as has also happened on this specimen.
Finally, the "wheel" on the reverse of this specimen was originally made of a separate piece and expected to turn. It is naturally a single piece on this electrotype.
Oh, and for this piece the original was brass, not copper.
As it happens, there's an original of this medal on eBay now. Curiously, this isn't a very rare medal, and I don't think it ever was all that rare. I don't know why someone would have taken the effort to produce an electrotype in the first place.
An electrotype is a kind of counterfeit, but not necessarily produced with intent to defraud. A lot were made in the 1800s as a way for collectors to finish their sets even when some pieces were unobtainable otherwise. They were also used by museums for the same reason.
Electrotypes are produced by electrically plating a thin layer of metal onto a real specimen. Two half-shells are made, and peeled off each side of the original. They are then joined and filled (typically with lead or solder or some low-melting filler).
The example here is particularly poor quality electrotype. Because of the way that they are made, electrotypes will have seams where the two shells are joined. I have a much-better quality electrotype where the seam is right at the "corner" where the edge of the medal meets the face, so it's hard to spot unless you're looking for it. On this medal, the seam is right down the center of the edge. Also it appears that only the reverse shell got an impression of the original reeding. The seam is more or less visible around the whole circumference of the medal, but it's super-duper obvious where a rim ding caused it to separate even further.
This example also shows significant bulging of the obverse toward the upper right quadrant (the horse's head and surrounding area). This happened when the filling material wasn't flat between the shells.
On low-grade electrotypes, the shells may wear through to show the filling material, as has also happened on this specimen.
Finally, the "wheel" on the reverse of this specimen was originally made of a separate piece and expected to turn. It is naturally a single piece on this electrotype.
Oh, and for this piece the original was brass, not copper.
As it happens, there's an original of this medal on eBay now. Curiously, this isn't a very rare medal, and I don't think it ever was all that rare. I don't know why someone would have taken the effort to produce an electrotype in the first place.
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<< <i>Electrotypes are produced by electrically plating a thin layer of metal onto a real specimen. Two half-shells are made, and peeled off each side of the original. They are then joined and filled (typically with lead or solder or some low-melting filler). >>
You can't just electo-plate a coin and then peel the plating off. The original coin was pressed into a piece of wax. The wax impression was then coated with powdered graphite which was then electro-plated to form the shell. The wax was then melted away and the shell was trimmed down to make the coin.
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the process alluded to by PerryHall seems to be a form of the lost wax process which i'm also all too familiar with, having worked in both Steel and Aluminum foundries using the process. the coin/medal would need to be replicated somehow in wax which is then coated in a very fine medium(we typically used sand or a silica substance) to build up a thick shell. the wax is then melted to leave a mold, at least that's the process we used to make such things as airfoil turbine blades and all sorts of pump housings and parts.
i can't speak to how the copies of coins and medals are made, though, just how the processes you've both described work. PerryHall's description seems accurate but the term electrotype as applied to it doesn't fit with how the term is commonly used in industry, at least not the way i'm accustomed to using it. to my way of thinking the process seems closer to a hybrid of electrotyping and the lost wax process. leave it to the scientists among us to discover how to make forgeries, though.
I can't complain when I learn something from my own posts. Thanks, PerryHall!
<< <i>Looks like I was wrong. I thought they were produced in the way I said (with the original coated to prevent the shell from sticking), but I cant find a reference that agrees with me. I can find a reference (from PCGS, no less0 that agrees with PerryHall. So: listen to him, but look at my pics.
I can't complain when I learn something from my own posts. Thanks, PerryHall!
Now you're starting to sound like me when I make an educational post and wind up with egg on my face. Welcome to my club.