But does it get rid of the zinc as good as sulfur?
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Copper sulfate has sulfur in it. So the short answer to your question is yes. Just depends on how much zinc you’re trying to remove.
I just realized that the copper sulfate that I ordered, and should be here, tomorrow…. Is in crystal form. I read in one of these threads that crystals contain water, and can’t be directly added to the pot? How are they added? The description is fine crystals, but further down, it reads powder. The product pic shows really small blue crystals.
Please forgive my confusion…
Krh1326, I use the blue crystals also. Just spread the crystals across the hot melt, it should dry quickly! Then just stir it in, it’ll do what it does! DO NOT breathe the fumes. Once is all it’s going to convince you not to do it again! Be safe,
Wow, this really is a great thread!
I used copper sulfate, zep root killer, to skim off zinc that I missed . Lost about 8-12 lbs. Out of a 50 lb block. My next casting session I'm going to empty my pot and try what I melted today. Fingers crossed.lol
Zep Root Kill works for me. I melted a piece of zinc into lead as a test - turned into a slushy mess. Added copper sulfate a few times, and now the lead is great for casting. I think you can overdo the copper sulfate, and just create more & more slag after all the zinc is gone.
I added 200 grains of zinc to 4 lb of lead, giving 0.7% zinc. I didn’t consider how much lead I lost, but after going through the process I’m sure it’s a measurable quantity. I just wanted to see if it really worked. The lead did go from trash to useable alloy.
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It’s so much effort that I’ll only do this for special cases.
I just posted to this thread so I can find it again.
I did not find any reaction with the sulfuric acid and wheel weights. I did however find a reaction using muriatic acid and wheel weights. A couple of drops on a suspect bare piece of suspect lead will bubble up indicating the presence of zinc or not. I use it on lead that I cannot readily identify. Sulfuric acid works great for "etching".