I've made a couple of rudders and leeboards, and they have all been weighted with lead. When I did these, I worked with only about 3 or 4 pounds at a time. My set up was a camp stove and a tin can with a handle bolted on to the side. It worked just great. But, I need to melt at least 20 pounds of lead at once and my little tin can was not going to work. I bought a fryer stand and a 10" cast iron dutch oven.
I decided to smelt all the wheel weights into ingots, and then I will take those ingots and make my pigs. I used a muffin tin for the mold and each one is about one and a half pounds each. I ended up with 105 pounds from the wheel weights and 110 pounds from the ingots that I bought.
Wheel weights. Not all are made of lead. Some are zinc and some are iron. The iron weights usually have "Fe" stamped on the back, but not always. You can figure to get about 75% to 80% useable lead out of collected wheel weights. Assuming that my pile was normally what you would expect to get from a tire store or garage.
This is a very dirty, stinky job. The road grime burning off the weights smells awful. Even standing up wind, I could still smell it. But, after you fish out all the clips and skim the dirt and crud off, you end up with pretty shiny liquid. And hot, very hot. Lead's melting point is 621 degrees F. Safety first!