Glass: A Pocket Dictionary Of Terms Commonly Used - Corning ...

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Fire clay: Clay capable of being subjected to a high
temperature without fusing, and therefore used for
making crucibles in which glass batches are melted.
Fire clay is rich silica, but it contains only small amounts
of lime, iron, and alkali.
Fire polishing: (1) in the hotshop, the reintroduction of
a vessel into the glory hole to melt the surface and
eliminate superficial irregularities; (2) in kiln working,
exposing the object to significant heat so that it assumes
a smooth surface.
Firing: The process of (1) heating the batch in order to
fuse it into glass by exposing it to the required temperature
in a crucible or pot, (2) reheating unfinished
glassware while it is being worked, or (3) reheating
glassware in a muffle to fuse enamel or gilding. The
melting of the batch may require a temperature of
about 2400°–2750°F (1300°–1500°C), whereas the muffle
kiln may require a temperature of only about 950°–
1300°F (500°–700°C).
Firing glass: A drinking glass with a bowl, a short stem,
and a thick foot. on ceremonial occasions, firing glasses
were rapped loudly on the table, making a noise that
resembled a volley of gunfire.
Flameworking: The technique of forming objects from
rods and tubes of glass that, when heated in a flame,
become soft and can be manipulated into the desired
shape. Formerly, the source of the flame was an oil or
paraffin lamp used in conjunction with foot-powered
bellows; today, gas-fueled torches are used.
Flashing: (1) The application of a very thin layer of glass
of one color over a layer of contrasting color. This is
achieved by dipping a gather of hot glass into a crucible
containing hot glass of the second color. The upper
layer may be too thin to be worked in relief. “Flashing” is