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ARTIFICIAL DENTURES. 79
We should ill nearly all cases reject a mold from which the
cast had fallen out by its own weight.
The *'Hawes" or Sectional Molding Flask.—It fre-
quently happens that the case in hand presents such decided
undercuts that it will be impossible to obtain a correct mold
in the manner just described, as the sand would become
impacted in these depressions and be broken away with the
model wdien it is dislodged. This can be readily overcome
by employing the sectional molding flask invented by Dr.

Fig. 44.

Fig. 45.

G. W. Hawes. It is composed of two sections or rings.
The lower ring is composed of three movable pieces, with
large extensions which project tow^ard the center as repre-
sented in Fig. 44. When in use these pieces are kept in
place by passing pins through the joints. The cast should
now be placed inside of this ring; the portion representing
the alveolar ridge should extend slightly above the top of
the ring, as showai in Fig. 45. The sand should now be
packed in around the cast to a level with the most prominent
points on the outside of the ridge. The surface of the sand
should be finished smoothly, descending slightly tow^ard the