Sprue and vent systems of wax are attached to the wax model by which the heated wax will later flow from the mold and the molten bronze will enter, then the dipping process begins.
The wax model is coated with a
refractory ceramic material then
coated with sand.
  The refractory-sand process is repeated several times over a period of days under constant
temperature and humidity requirements until a desired thickness is reached.
After the shell is thoroughly
cured the piece is placed in
a kiln for hours to remove
any moisture and eliminate the
wax creating a positive void in
which will be poured the
molten bronze.