I did 4800 lbs of wheel weights in the build of my Bristol Channel Cutter, I could have bought the keel fish for much less ( I think at the time $1200), but in the time it took me to pay off the hull and deck we were in the 1979 run up of metals, gold hit $900, lead of course followed. I poured mine directly into shallow molds that would fit in the keel, I used something like waterglass to cover the molds so little burning.