Originally Posted by
jonnyjeb
I've melted copper and aluminum with a home made propane forge. I found that I lost a lot of metal due to oxidation and impurities floating on top (dross). There are ways to combat this using different fluxes but when I took a beautiful 5 lb copper ingot to the scrap yard they weren't interested. One reason is that they couldn't see inside the ingot (and didn't want to test it but cutting or such) and they also couldn't tell if the copper was pure or an alloy of itself and some heavier, cheaper metal. I sold the forge.
Scrap yards often are not equipped to assay metals. They do often possess and use XRF guns or analyzers, however they only check the surface of the metals, and cannot penetrate deeper.
If you take your ingot instead to a refinery, they will generally drill it and then either fire or xrf assay the shavings. If you ever decide to take your ingots to a refiner, and they have precious metals in them, make sure you ask for a referee sample as well in case you don't agree with their assay. The should be drilling the ingot on the top, at both ends and the middle, and the bottom at both ends and the middle and then taking equal amounts from each drilling, mixing them together and then splitting the sample into three using the proper method. One for them to assay, one for you, and one referee sample in case you don't agree.
Scrap yards act as the middle man between yourself, and the refinery or industrial buyer. Whenever possible you should go directly to the refiner. You will make more profit in doing so.
Scott
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