I had a pile of old sterling cast sprues with buttons that I melted down with 92.5 g fine silver plus the 7.5 g of copper and poured all into a bucket filled with water to make more usable sizes of sterling. It turned out white with quite a bit of yellow here and there. Did I accidentally melt some gold in with it? Or could the yellow be from the copper that didn’t mix in well? And if some of it was gold, is there any way to separate the metals now? Thank you in advance.[https://photos.google.com/photo/AF1QipO7wi1N1Ne_invIyooKDfkwccgvDuT0vw9iDF9T]
Sadly your photos don’t want to open. So I can’t see the issue.
I have questions.
Did you use a torch for melting the metals? If so, what kind?
Which metal did you melt first?
When alloying metals it’s important to melt the highest temp metal first and then add the lower temp metals. So with the metals at hand that you mentioned, the copper should have been melted first, then the .999 silver and then the old casting buttons. It’s also important that the metals all be in the form of small casting grains or cut up into equal size bits. The smaller the better. So were it me I would have first melted and poured the old sprue buttons and poured them into water to make small grains. Then cut or melted the other metals to roughly the same size. It’s imperative that the metals must be very well mixed.
Copper can be a real bitch to melt. It takes really high heat, 1984 F. It’s really best to be melted in an induction furnace. It also loves to absorb oxygen. If you are going to torch melt it it’s better to use an oxyacetylene or Mapp gas torch. I prefer Mapp.
Me? I’m lazy. I just send our scrap to the local precious metals refinery. After assaying and determining the scrap value, rather than take money they give me the refined metal. I never take money for our scrap. Why? Because it will be considered taxable income. Why pay taxes on metal that I already own? I always prefer that refiners give me the equivalent value in fresh casting grain. With our gold we ask for 24 kt casting grain and buy premixed alloy metals from the same refiner so that we can alloy the gold to what ever color and karat we want. If I want sterling grain I get it pre alloyed.
Hope this helps.
Thank you. This helps a lot. I use an electric melter. The red ones you see all over. I learned jewelry making 45 years ago and life got in the way until now so I am basically a newby all over again! (I think Yogi Berra said that!) 45 years ago Oxyacetylene was the only choice! Anyway, I just dumped all the metal in together, not cut up. The copper was a tiny amount in the whole bunch. 7.5 g in a total of around 450 g. I heated it to 1160 c. stirred it a few times while melting with a titanium? rod. I guess I could test the yellow parts for gold. I like your method better! Carey