Scott, the problem is the clay is drying out. Once it dries, it gets hard and loses its adhesiveness.
JB weld is not permanent. You can remove it by heating the mold over 600 degrees for longer than 10 minutes. Considering the melting point of lead is 612 degrees, this shouldn't be too hard.
JB weld is not permanent. You can remove it by heating the mold over 600 degrees for longer than 10 minutes. Considering the melting point of lead is 612 degrees, this shouldn't be too hard.