lead, tin, antimony?

[Bagdadjoe]

I've mixed up a batch of 30-1 for my Gibbs and see some stuff floating on top of my mix (which should be "pure lead" and tin). Even after fluxing it's there. So, I come here and read one of the stickys concerning alloys.

"Lead/antimony alloy drosses considerably. As your melt reaches liquidus temperature that silvery, lumpy, oatmeal looking stuff floating on top is antimony. Skimming it off seriously depletes the alloy; it needs to be fluxed back into the melt."

So, if I don't want antimony in my mix and don't know for sure that the "pure lead" is totally pure lead, should I skim that off. I don't want antimony or anything else in my long range muzzleloader bullets except lead and tin. Tin, as far as I know, does not float to the top?

[JSnover]

Make sure your temperature is not too high, so you don't cook the tin out. Flux and skim. Your tin should stay in the melt where you want it.

[Bagdadjoe]

I'm running at 750...to fill these big cavities. Don't think that's too hot..

[lwknight]

If you have tin in the alloy you will never skim all the antimony out.
The tin makes a sort of wetting agent that binds the antimony in the lead.
The more tin the more antimony it will hold. 4% tin can easily hold 12-15% antimony in solution. Even 1% tin can hold a few percents antimony in ternary alloy.