What is the purity of the silver layers in 40% Kennedy halves?

Well the coin itself is 40% silver, but it's not uniform as it has layers of silver-copper-silver, so I'm wondering about the purity of the silver layers, are they just 90% themselves?
Same applies to the silver Ikes.
Also why are they layered and not mixed into an alloy, even the modern clad coins?

(not my image)

 

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Maybe if the coin was not clad, the 40% silver would be dark and dull like an old 35% war nickel? Modern clad coins may look coppery with that high a copper ratio?

 

I think you are misunderstanding the meaning of 90% and 40%. Both contain pure silver, but those are the percentages of pure silver in the mix. A 90% silver half dollar contains .36169 ounces of pure silver. A 40% silver half dollar contains .1479 ounces of pure silver.

 

The outer layers on the 40% silver clad half dollars were 80% silver and 20% copper. The inner core was 20% silver and 80% copper. Therefore the core of these coins could appear to be a little "brown."

The silver clad coins were issued from 1965 to 1970. The 1970 coins could only be obtained from Proof and Mint Sets.

 

The faces are 80% silver and 20% copper. The core is 21.5% silver and 78.5% copper.

 

The lesson of the day, thanks everyone, I learned something new. Be safe

 

Half dollars made from 1965 through 1970 are made of two outer layers containing 80% silver and 20% copper with an inner core of 20.9% silver and 79.1% copper (net composition: 40% silver and 60% copper).

As far as the silver,when separated from the copper, 0.1479 troy oz of .999 fine silver.

I think all of this was said in different posts, but that sums it all up.

 

I'm not trying to start anything but we have 3 answers to the composition of the inner core of clad halves, and they're all 3 different. Why is that?
Again, I'm just curious.

 

A fine question worthy of an answer, but I'm not sure there is one. My answer was based upon the Coin World Almanac, which I was a contributor to when I worked for Coin World back in the 1970's, though that particular chart of U.S. coin specifications had been prepared by Ed Fleischmann for the Collector's Clearinghouse page long before the Almanac was published.

I worked for Ed, and he was fairly meticulous about such things, but I do not know where he got that specific percentage. The 1971 Mint Report is useless; it gives the percentage of the core as "approximately 20%," which only guarantees that the percentage is not precisely 20%.

If the thicknesses of the three clad layers are proportioned 1-4-1 as were the copper-nickel clad coins of the era, then the two 80% clad layers together weigh 3.833295 grams and the core weighs 7.666705 grams. The two 80% silver clad layers would contain 3..066636 grams of silver. At .200 fine the core would contain 1.533341 grams of silver. Combined they would contain 4.599977 grams of silver, approximately 11.50 grams gross weight times .400 fine which equals 4.600 grams net silver content.

So, upon further review, I would say that "approximately 20%" figure is closer, but it is never going to be precise

 

Thanks for ''assaying'' a reply.