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When ready to
cast, a sprue is added to the model and it is attached to a base, (right)
Then the model
is placed in a sealed container and investment is poured in. This flask
is heated in a kiln until all of the wax melts out through the sprue
channel and burns off, and only a hollow space remains inside the investment
where the wax was.
Making the Wax Models: A wax model can be made either by the additive method, using soft wax and adding decorative elements,(upper left); or by the subtractive method, using hard wax and removing material to make a design,( upper right).
Heating
the gold in the crucible with
an acetylene torch until it is molten.
Molten gold above,
with warm flask in place in front of crucible.
Ready
to drop the pin to start centrifugal action to force molten gold into the
flask to fill the space left after the wax model was burned out in the kiln.
The spin.
Empty crucible
Flux
covered gold sprue is visible,
hopefully indicating
a successful casting.
The
flask is plunged into a bucket of water, the investment falls off and
and the ring is
freed. This
photo shows the investment remaining around the ring and the sprue.
.
Rings in unfinished state, investment removed.
Sawing
off sprue, cleaning and
filing rings before final finish.
Finished
rings