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I heard from another caster that he used bronze ingot molds for the excess metal from a heat. I had been using a rammed sand mold for the excess and I figured a perminant mold would be just the ticket. Finally getting some discressionary time I designed and built a pattern and cast two molds from it.
The only difference in our casting routine now is that we have to remember to preheat these ingot molds to drive off any moisture before we use them and give them a coat of soot or graphite so the hot metal dosen't fuse to the mold.
The mold as designed is 8.3" long x 3.8" wide x 2.3" high. The wall thickness is 3/8". It will consume five pounds of bronze not counting the sprue, gates and runners. I cast the first one with the opening facing up and had some inclusions that needed to be polished out. The second one was cast facing down and the inside came out perfect. The outside had some rough spots, easily polished out, but they didn't mater. In the sand, I used my burnishing ball to press three concaves into the sand to make three domes on the bottom of the part so it would sit a fraction above the suface and not rock around. Not on the plans are two small holes through the bottom of the pattern for draw screws.
Click here for the plans.