Iron County register. [volume] (Ironton, Iron County, Mo.) 1867-1965, 1890-09-11
ABOUT PLATE GLASS.
How That Which Is Cast Is Manufact
ured and Finished.


The most important form of cast
glass, and the most largely produced, is
plate glass, or, as it might more prop
erly be called, cast plate glass. This is
the well-known cast, ground and pol
ished plate used for windows, mirrors,
etc. and should not be COMPOUNDED with
the blown plate and patent plate, which
are blown glass In the manufacture of
cast plate furnaces and pots of the ordi-
nary construction are used, the melting
pots, however, sometimes holding Two
or two and half tons of hatch. In
French works and in some others, two
forms of pots are used. which are placed
side by side in the furnace, the ordinary
melting pot, and an auxiliary pot called
'curvette," large enough to hold suffi-
c1ent glass to cast sheet of given
size. The molten glass is ladled from
the pot into the curyette, allowed to
clear if necessary, and is then cast In
most works, however, the practice is to
pour or cast directly from the pot in
which the glass is melted, and in other
cases it is ladled from the pots to the
casting table.
The casting-table. formerly made of
iron, heavy AMI thick, and in width and
length exceeding the dimensions of the
largest sheet glass. 1t is commonly
mounted on wheels, running on a track
laid down the center of the casting
room, on each side of which are the
annealing ovens.
A heavy cast iron roller the full
breadth of the table is arranged to roll
its whole length by means of spur
wheel on the roller working gearing on
the side of the table. The height from
the table at which it rolls. and conse-
quently the thickness of tho glass, is
regulated by narrow strips of metal
placed along the edge of the table,
while the width is determined by what
is known as the gun" two plates of
cast metal bolted together, adius table
to the breadth desired, and moving with
the roller and Def ore it. All being
ready for casting, a pot filled with the
molten glass is removed from the melt
ing furnace, placed on truck and run
to the casting table.
The pot is lifted from the truck by
means of a crane, is suspended over one
end of the table and tilted and the
semi-fuid mass being poured out, the
roller is moved forward. f1attening the
glass and rolling it into uniform
thickness, while the gun prevents it
from spreading to greater width than
is desired. AS soon as the plate has
soliditied sufficiently to bear moving, it
is laid in the annealing oven on the
flat to slowly COOL All the opera
tions are performed with the greatest
rapidity, that the plate may be as hot
as possible when laid in the oven. The
number of plates that can be put in an
oven varies with the size of the plates
But one layer of those designed
for polishing can be placed in Git,
consequently large number of ovens
is needed where large plates are made.
These ovens are large, shallow brick
furnaces, with floors as smooth and level
as possible, as the semi-plastic mass
molds itself into the unevenness, and
any bending of the plates would make
them valueless. AS soon as the plate is
placed in the oven all the openings are
carefully closed, and the oven is al
lowed to cool gradually to point where
the glass may be safely removed, gen.
orally requiring about three days. The
cast plate as it comos from the oven is
rough and irregular on it's surface, con-
shutting the rough glass of commerce,
and in this form it is used for roofs and
floors, and even windows where light
without transparency is desired. Amer
lean GlaSSwOrker