Orleans County monitor. [volume] (Barton, Vt.) 1872-1953, 1889-04-29
The Manufacture of Window Glass.

simple, and yet requires such rare
skill. as the manufacture of window
glass. None of the delicate tools
used in other processes are required
in this one, all the most eXacting
work being done with a simple blow
pipe and glaciers diamond. AnC
so for this very reason, if for no 9th
er, there is no more interesting pro
cess to be seen anywhere than that OF
window glass making, interesting not
only because of the remarkable dex'
terity of execution displayed by the
workman, but also because that il
can readily be understood by the IN
initiated observer. A description OF
the process, therefore, as witnessed
in the works of the French Window
Glass Manufacturing Company, St
Louis, will doubtless furnish pleas
ing, as well as instructive reading.
The raw materials required in man
ufacturing glass are mixed in the fol-
lowing proportions Sand, 100 parts
salt cake, forty parts; limestone.
thirty or thirty-siX parts, and arbitra-
~ quantities of arsenic and charcoal.
Salt coke is the bi-product left in the
manufacture of muriatic acid. These
materials are ground as finely as pos
sible, and then thoroughly mixed in
bins, which, being mounted on wheels,
can be moved directly in front of the
furnace containing the melting pots,
according to its size, which are so
suspended that they come in immedi-
ate contact with the fire on all sides.
The pots are made of fire clay, and
hold about 100 gallons of molten
glass. Although made with great
care, the clay being tramped by foot
over and over every few days for
from six weeks to three months, their
average life is only about five weeks.
The fuel used in the furnace is soft
coal, a ton or two of which is kept
burning constantly from the time the
works start up until they close, a pc
Rod of from eight to nine months.
The furnace itself is great pit, I'M
der which is long tunnel twelve feet
deep by ten feet wide. A CRATE in the
bottom of the furnace opens into the
tunnel, and when the glass is being
melted the doors of the tunnel are
opened, creating a strong draft di-
rectly into the furnace, which attains
a heat of from 2OO0 to 5000 degrees.
When the sand is thoroughly melted,
the tunnel doors are closed, reducing
the heat in the furnace fully one-half,
and everything is now in readiness
for the blowers. 1t should be eX-
planned here that in each pot is a
ring of fire clay, about half the diam
eter of the pot, or about two feet,
which floats on the surface of the
molten glass. This is used to obvi-
ate the necessity of Swimming the en-
tire surface of the liquid when a guam
tity is taken out, as it is always lifted
from the center of the ring.
Now that everything is in readi
ness, a workman takes a long, hollow
piece of iron like gas pipe, about
an inch in diameter, with the orifice
about half an inch in diameter, and
inserting one end into the molten
glass, rapidly revolves it until
sufficient amount of the glass adheres
in an irregular-shaped mass. Quick
ly withdrawing it, he lays the end
holding the glass into q dish-shaped
iron mold, and. rapidly revolving the
tube or blow pipe, for such it is,
forms the glass into perfect sphere
or ball. 1t is then handed to the
blowers assistant, who lays it in an
other semi-circular open mold, and
then revolves it by means of the pipe,
blowing into the pipe all the while.
The ball now begins to fill with air,
and expands at the side farthest from
the blower, until it assumes the size
of the mold. 1t now resembles, as
near as can be described,a large soap
bubble arising out of a solid mass of
suds, much smaller than the bubble
itself. This bubble determines the
size of the cylinder to be blown.
The pipe is then handed to the
blower, who stands on narrow plat
form in front of a long, narrow and
deep pit. At one side is furnace
with open doors, showing the intense
heat of the fire within. The blower
dextrously thrusts the end of the
pipe holding the glass into the oven
until it is thoroughly heated again,
and Withdrawing it swings it into the
pit in front of him. Now, with
EhO0All " 0IO PlpCs hC SiO"it o"lhS0
1t to and fro in the pit, expelling air
from his lungs through the pipe into
the glass all the while. The glass be-
gins to take the form of cylinder,
growing longer with each pendulum
motion, but retaining the same diam
eter as the bubble first formed. Sew
eral times the blower stops long
enough to thrust the cylinder into the
furnace, and then resumes his clock
like work The result is cylinder
of glass about three feet in circnm-
ference and five feet long, containing
about fifteen square feet of glass.
The far end is again placed at the
opening of the furnace and heated to
higher degree than the rest of the
cylinder.
Blowing into the pipe and holding
his thumb over the mouthpiece be-