I had a chunk about 20 lbs one time. Tried hack saw no go. Fine tooth blades the lead clogs them up. Ended up borrowing a Sawsall with rough cut blade. More work than I want to take on again. I would say about 3 inches and about 6 inches long would be the biggest I would want to fool with. If you had a outside heat source like a fish fryer you could use and old pot and make something to pour it into to make ingots. Don't get mad at me but this fooling with hot lead is very dangerous and you need to take precautions when fooling with it.