Help with sintered planchets

Madman · New Member

Hi all,

I have been seeing a lot of listed coins saying they are "SINTERED PLANCHETS" and Fred Weinberg has one listed that he calls "Black Beauty".

Now I have no idea what a sintered planchet is or how to determine if a coin is struck on a sintered planchet.

ANy help?

Bob P · Site Admin

Madman....I think a Sintered Planchet - is a planchet that was copper washed. I am not absolutely sure, and if I am wrong, I am sure someone will straighten me out.

Madman · New Member

that is what I have been hearing. What has thrown me is the color. Some say a sintered planchet can be identified by its copper color, but people are selling sintered planchet coins that are black, and another one I found was gold.

Bob P · Site Admin

That's about the same I have heard. I think the washing has caused some sort of patina that ranges from coppery color to black.

Robert · Senior Member

I haven't heard that one.

In manufacturing, "sintering" is taking a powder (either powdered metal or ceramic material), pressing it in a mold and then heating it until the powder grains start to melt on their surfaces. The powder fuses into one piece.

I have no idea what the coin-related definition is.

Madman · New Member

here is the link for the coin that Fred Weiberg is selling maybe that will help

http://www.fredweinberg.com/inventory/item.asp?ID=3017

Bob P · Site Admin

Well, this 'Sintered planchet' thingy made me do a little more research. The following links show what I managed to find concerning sintered stuff. Robert....You are also in the ball park with your explanation. The following quoted material is from James Wiles and his pdf copy of 'Numismatic errors'. You must have Adobe reader to view the file:

http://www.money.org/AM/Template.cfm?Section=Home&TEMPLATE=/CM/ContentDisplay.cfm&CONTENTID=1656

For those of you who can't download this Adobe file, his definition for sintered planchet is: 'These planchets were kept too long in the annealing drum. In the process, they became coated with a layer of metal dust that was 'sintered' or melded with the planchets. Specimens are known with partial, single-sided, or doubled sided sintering."

Another link I found that gives a description of sintering is below. However, the two don't quite match.

http://hermes.csd.net/~coneca/club_conecafrm40.html

Hope this info helps!

Madman · New Member

Well this has turned into a mystery for me!

I am wondering if there is a difference between a sintered and a copperwash? Could it be that the sintered planchet coins can be "sintered" with metal dust other than copper?

For instance, I have found a state quarter that has a nice "gold" patina all over. It has been said that this is also a sintered planchet and called a copperwash as well.

Madman · New Member

are all coins annealed in the same furnace?

Bob P · Site Admin

I don't know the answer to that Madman. I would assume that metal dust from any coin(s) could meld onto the surface of another coin. I would also think that might be the reason for the 'Black Beauty' coin being offered for sale. As far as whether or not the annealing furnaces are different for different deniminations of coins, I wouldn't think so.
Please understand that I am doing research on this subject to try and help you out, and teach myself something on the subject. Anything I say here that is not attributed to someone else may or may not be accurate. I have just been using the internet search engines to find what I have posted here.

Madman · New Member

Bob,

You have been of great help already. Thank you very much!

It just seems that most of the info that I could find while searching was sketchy at best when it came to sintered planchets. But my thoughts were the same as yours, you would think that all the different types of metals used in the mint would also adhere. Therefore making coins of different colors.

coop · Expert Member

Possibly the material for the planchets, the raw metal had imperfections in it. I don't think they would harden the metal as the dies are hardened. The dies would not last as long if the metal was hardened. But in the case of layered planchets like quarters and Dimes and Half dollars I'm not aware how that metal is formed. It may be heated to get the sandwiched metal to adhere to it self? Not sure about that. If the metal was heated it could off color the raw materal. Not sure how that is exactly made. It could be rolled hot together to form the material? Just an observation....

Madman · New Member

ahhh, the plot thickens! lol

Well, as of today, I have found two more that fit the criteria that others have laid down for sintered/copper wash planchet coins.
I was thinking of sending them away to be graded, but I don't want to waste my money.

Matt Dinger · Advanced Member

could it happen that the planchets are not washed in the acid bath.....and annealed covered in metal dust and crap.....and it melts and burns onto the planchet.....kinda like burning a cookie....just a thought....i honestly don't have an idea on how it happens....need to send a couple of e mails to people