High arsenic lead?

[lwknight]

I have a good bit of soft lead that has no surface tension at all. I know that shot makers use arsenic to get rounder balls and that faster age hardening is a by-product when antimony is added.

Arsenic in itself does not make alloy harder to speak of.

I wonder if someone could describe the ingots differences when arsenic in in the alloy?
My normal ingots have a rounded edge and some mystery lead has very sharp edges.

Also the dark grey and high melt temperatures indicate that there is no tin at all involved.

[felix]

Arsenic and aluminium are two of many culprits to make really hot lead drop rounded cold corners in hot molds that typically would be making excellent frosted boolits with shootable lead. If those boolits made with your lead are not harder than normal, then the bets would be an aluminium contaminant present (because of its availability in really junk lead). Yes, arsenic will harden boolits on its own merits. The difference between arsenic additive versus antimony additive is the size of the finished boolit. Antimony is about the only good or bad element found in our lead that expands upon cooling. ... felix

[lwknight]

Does arsenic increase surface tension or decrease tension. I get square sharp edges with very soft lead.
Normally my known pure lead has somewhat rounded edges. A small drop like #4 shot sized pure lead will stay in a ball. This mystery stuff flattens out like water. And its still very soft like pure lead and the melting temps are the same.

[felix]

Increase. Best decreaser is tin. ... felx