Dogleg - go here if you have not seen this already - http s://www.westernmetal.ca/product/pure-antimony-1-lb-ba-sb/ Some years ago I ordered some other stuff from them, when I was casting, and got at least one bag of one pound 100% antinomy - was various "chunks" as I recall - not an ingot - you can do your own math to get the mix that you desire. As per Post #5, I thought it was as simple as to just melt it together with lead - was what my plan was, although I never did follow through - I sold off most all of my casting stuff and that buyer got the bag of antinomy.
You might not need to buy any tooling for this - for years I used an RCBS cast iron pot - maybe held 10 pound lead?? - on a propane camping stove in my garage with East and West doors open. I melted down many 20 liter pails of wheel weights that way - adding sawdust for flux and using wood stick as stir stick, then scooped out clips and crap with a largish spoon. Might have to give it a shot with propane plumbers torch along outside of that type of pot to get extra heat to melt the pure antinomy, but I think is like many alloys - melt temp get LOWER than the constituents - is actually a "eutectic" temp in some alloys that is lower melting temp than any of the parent metals used to make that alloy.
