Cladding processes
DDP
Posts: 3 ✭
Two cladding questions:
How does the cladding on golden dollars wrap around the edges? On other clad coins you can see the three distinct layers: copper-nickel top and bottom, copper center. Golden dollars are obviously manganese-brass in a single layer wrapping all the way around (with the exception of errors missing the cladding on the edge).
Why do some silver-clad Kennedy halves appear to be solid silver when viewed along the edge, while others from the same year have visible copper on the edge? It seems a number of people in Internet Land have noticed this, but I haven't found any explanation.
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Short answer is metal flow during striking.
If I read your questions correctly, here are my answers....
Golden dollars do not have "wrapped around" cladding on the edge. They have three layers like other clad coins. New dollars will show little if any difference in the colors of the layers. Once they tarnish from circulation the layers become more obvious.
As for 40% silver half dollars, it's a similar situation. The middle layer is not copper - it is a mostly copper low grade silver alloy, but it will appear very silver in color when new. Once it tarnishes the middle layer gets darker.
The layers, or their perceived proportion to each other, can sometimes be impacted by the process where planchets are punched from the clad strip. The outer layer can get pushed down slightly at the edges during that process.
That makes so much sense! And it's such a simple, pragmatic answer, I can't believe I haven't thought of it before. Thanks!
I guess the same applies to Shield cents? I often see them described as "plated," but that's a different process than pressing three flat layers together.
Different process. They start as zinc planchets then are plated with a thin layer of copper.