
5. Coat the inside of the flask with a petroleum jelly. This will prevent
the stone from adhering to the flask.
6. Invest the partial using regular Buff stone. When stone sets, place
sprues using 3/16” (4.75mm) utility rope wax. Extend the sprue to
the injection port in the flask.
7. Coat the stone with stone separator and bolt the top half of the
flask in place. The utility wax should fill the injection port of the
flask. This will keep the stone from leaking out during the second
half of the investing process.
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