It goes uphill from here, boys and girls: Regarding clad metals: 1. What mix of metals make up our modern clad coinage? (Percentages for extra credit!) 2. There are layers of different metals formed together for the clad sandwich. How many are there, typically? 3. How are the layers united to create the coin strip ready for planchet punching? 4. What temperature is typically used to make question 3 possible? 200-400 degrees F 400-800 degrees F 1000-1500 degrees F 1000-1500 degrees C And just for giggles: Name a company that supplies coin metal to the US Mint?
Here's one for you Chris - what was the old method used to bond the clad layers together ? ( Before they began using the method you are asking about. )
The old method of bonding two strip layers together was to use an explosion. The concussion would bond the layers of metal together
Joe, you've hit #1, 4 and almost on three. What kind of pressure? Two layers is not correct. Maybe another try?
What kind of pressure? The pressure your wife puts on you to attend her 3rd cousin twice removed babys shower. Man, that's a lot of pressure. Could be there is some heat involved? My sources say two layers.
Well, here are the answers that I had researched... There are three layers of metals, an obverse and reverse cupro-nickel clad and a inner core of copper. They are welded together at the edges, heated to 1000-1500 degrees centigrade and fused together in a process called hot rolling, where controlled drums roll the hot metal layers into a single sheet. They are then coiled up and sent to the Mint. One of the vendors is Olin Brass.
Except on what I call an "open face sandwich" like the bicentennial quarter I found in a mint bag in 1976, with no cu-ni layer on the reverse.
