yes DD thats also one way to do it , but Im not sure I agree with you , that mean more work then neccesary
Im an lazy man
balancing weights , both lead and zink is not pure metal , its alloys containing lots of other metals .
in the lead weights its a few % antimon added in purpose to have the lead harder
thats why you shouldnt use wheel balancing weights for casting minie balls for muzzle loading rifles , just pure lead with 4 - 5 % TIN TO DONT HAVE LEAD BUILDING UP AN FOULING IN THE BARREL .
but to produce cannon balls I dont think its of any importance if you have a few % extra lead in the zink alloy as most of the zink alloys already have a few % of lead in it . its to make it better to fill complicated molds , if you want an higher quality zink you use tin instead , but its more expensive .
and if you keep the liquid metal at 600 degress celsius ( or more ) for a while and stir it a few times most of the lead will float at the top as oxide and you could skim it off . or if you want to take it all away you can blow some oxygen through the liquid metal from the bottom of the crucible . that will speed up the oxidization of the lead considerably . I use an 1/4 inch stainless steel pipe 4 foot long that are connected to my oxygen welding tank .
but back to the lead again , as the only purpose here is to cast ingots I dont think its neccesary to skim the oxide off and flux it , as you will do that when you remelt the ingots and use the metal to an purpose , whatever it is .
about using the same crucible I dont know , but I use the same for all my melting except for bronce castings when I dont want any contamination in the cannon bronze .
but thats the way I do it , and as I said before Im an lazy man
