I don't flux when I cast, I scrape up the mush and put it in a coffee can. I bang the dipper on the coffee can, mush sticks there also. I don't know what the mush is, but I know what it does, and what it isn't.
What it does:
I take half a pot of clean WW alloy, and put in the mush from the coffee can. Half a coffee can is about 2500 bullets worth of casting, about 6 months for me. I flux the dickens oit of the melted mush, and it goes away, leaving some black powdery stuff on the lead. I scrape this up and throw it away. There's about half a dipper of black powder stuff.
What it isn't:
It isn't tin and it isn't antimony and it isn't oxidized tin or antimony. Tin or antimony or arsenic won't come out of the mix when it's melted. The reason I know this is that bullets cast from a pot of alloy weigh the same, even though the mush is scraped off into the coffee can as casting progresses. I weighed every bullet for so many years that I know and will be happy to demonstrate that bullet weights remain the same. And since the density of tin, antimony and arsenic are different than the density of lead(lower, if I remember correctly), then removing some of any of these alloy elements will change the density of the alloy and the weight of the bullets. It doesn't, and I'm real sure.
Melt it, flux it, get it good and hot, and you'll end up with the black poiwdery stuff you can throw away. Or, just throw it away. Mox Nix, as we used to say.
joe b.
