This was a kit sold for children 12 and up, which let them create metal soldiers and other figures. The kit included a crucible, a heating unit, and lead ingots that you would melt in the crucible, to then pour the molten lead into molds.
I assume you could then paint the resulting figures, if you wanted.
Here is a photo showing those components. The crucible and electric heater are on the right. I suppose(?) you would file or trim away the flashing and pour-funnel from the final cast figure, but this photo shows the result straight out of the molds.
Ages 12 and up.
That seems possible.
I did some searching and there are sites that claimed the metals used in home casting kits varied, and were often an alloy of tin and lead, but could also be pure lead, pure tin, pewter alloy made without lead, or some kits would also use molten plastic.
So through history it sounds like it varied a lot as to materials.