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ARTll'IClAJ. DKXTURI-: LH'ON CAST METAL BASK. lOI

articulated and waxed up, the case is now ready for the
Mask. One of the best adapted flasks ior castino^ is shown
in Fig. 60. The i)iece is tlask-ed in the same manner as
for rubber work, except that the investment material used
should be the same as that employed for the cast. After
the investment has become sufficiently hard, the sections of
the ilask are separated, grooves or gatewa}"S are cut from
the posterior margins of the mold to the openings shown

Fig. 60.

in the figur«., lulio piwMMiUg for the pouring of the molten
metal upon the one side and the escape of the surplus up the
other; after which all traces of the wax should be removed
with boiling water.
The mold is next well dried by exposing it to an oven
heat for two or three hours; the sections of the flask are
then adjusted to each other, and tightly clamped to prevent
the escape of the metal when poured. Before bringing the
alloy to the fusing point (which should always be done in
a clean crucible), the mold should be tested for moisture.