Using US silver coins to make karat gold...

[evanJ]

Hi! I am approaching the last stages in my jewelry project, and am ready to produce 18 karat shot. I have about 27.5 grams of refined gold, and have settled on a "green gold" alloy described here as it should be the right strength and color I am looking for. Doesn't hurt that it calls for 9:1 Ag/Cu, which I happen to have a lot of in the form of US silver quarters and dimes!

Or so I thought... But when looking for evidence of this ratio of silver to copper, I couldn't find much proof beyond the claims of the US mint.
This is the only XRF I could find, which on page 6 lists the copper content at 12% and the silver content at only 82.5%

So I'm wondering...

• Has anyone successfully made an alloy of 75% gold, 25% junk silver from US coins? If so, were its properties consistent with what you would expect from 9:1 Ag/Cu?
• Do you know of XRF reports that prove the 9:1 ratio?
• Or - has anyone recovered 90% silver and 10% copper and nothing else from US silver quarters and dimes? It's my understanding that even a little nickel or zinc will botch my alloy.

edit: I might add that I've also recovered enough silver from my refining to use instead, and that I don't mind buying a few cents worth of copper... but it would be really cool to use the junk silver if that doesn't botch everything.

Thanks so much!
Evan

 

[goldshark]

To be certain, I would alloy with only known parts of .999 metals. To do so using Ag coin alloy could be a crap shoot. Ag content has varied through out our (US ) history. Do what you may, you are putting your stamp, and reputation on the line.

 

[nickvc]

I highly doubt that the mints claim is false but should you decide to use coins make are they are fully cleaned.

 

[goldshark]

I highly doubt that the mints claim is false but should you decide to use coins make are they are fully cleaned.

If I remember correctly, there are a few years (post 1964 ) where JFK half were like 40-50 % Ag/ Cu laminate.

 

[FrugalRefiner]

See US Coin Values.

Dave

 

[goldshark]

Thanks Dave, always amazed at how much info is here. I've been a member here for years, and thought I knew it all. I'm still getting surprised.

 

[eaglekeeper]

US war time nickels are only 40% Ag....I think 1942-1945.


edited to correct date.

 

[goldshark]

US war time nickels are only 40% Ag....I think 1941-1945.

Kind of interesting that the war time nickels contained 35% Ag. Only years they contained Ag.

 

[galenrog]

US war time nickels are only 40% Ag....I think 1941-1945.

Wartime nickel alloy was 56% copper, 35% silver, and 9% manganese. Part of 1942 through end of 1945.

Due to manganese, I would advise not using war nickels to make alloys for jewelry.

The document Dave linked to earlier shows composition of US coins. I have a similar, but much older, document in my files somewhere.

Also, the advice from nickvc to clean coins before use is good advice prior to any melt.

Time for more coffee.

 

[eaglekeeper]

Kind of interesting that the war time nickels contained 35% Ag. Only years they contained Ag.

I have a jar full of them, but I don't know what to do with them. I don't think they are worthy of processing yet and a lot of places aren't interested in them.