The Dalles daily chronicle. [volume] (The Dalles, Or.) 1890-1948, 1894-08-30
GLASS woRklNe.
The Delicate Process Is Attended with
Much Uncertainty.

Much Uncertainty.
A writer in the Optician states that
glass is substance which, as the glass
blower says, has a viii of its own. 1t
is very often difficult to tell how par
tieular piece is going to act under GER
tain conditions, even after having
tested other pieces Of the same batch. .
When subjected to the heat one end of
tube will sometimes respond diff
ferently from the other end. This is
in a measure due to unequal chilling,
occasioned possibly by a sudden
draught of air while it is in process
of manufacture No piece of glass is
absolutely reliable. It's working is,
therefore, at certain stages, most un-
certain, and one person may have en-
tirely different experiences from
another. Tt is chameleonlike, and
every process succeeds better with
those who seem to have a knack which
is generally obtained by long practice
The cutting of glass heads the list of
the uncertain processes, for it has no
definite cleavage, and its separation is
modified by the surrounding tempera-
ture. The simplest separation is on
fat glass in a straight line. Here all
that is necessary is a deep and regular
SSL OUCH Win d RlaZlCIS Nl1aIuOnO, d
firm and speedy bend away from the
main piece, and the parts crack along
the desired line. These GLACIERS dia-
moRds may be purchased and general
ly prove satisfactory, but it is more
economical to purchase from some dia-
mond cutter small splinter, and in
sert this into piece of brass rod hav-
ing1a small hole drilled into one end.
The splinter should now be cemented
with marine glue and the brass rod
fled little upon the side nearest the
ruler, to obtain, after trial, the best
cutting angle for the diamond. Another
instrument for cutting glass less ex-
pensive than the diamond is the glass
blowers knife, which is a piece of thin
steel tempered glass hard by heating
it cherry red and then plunging it into
ice-cold water or mercury. The edge
should be sharpened by rubbing it upon
an old, rough emery grindstone until
| fine saw-hke notches appear. 1t is
then ready for use and should, if much
used, be sharpened repeatedly.
To cut tubes, carefully scratch at
right angles to the axis deep notch,
either with the diamond, a triangular
file or glass blowers knife. Heat a
piece of glass rod until small globule
appears on the end and press this upon
the scratch. The glass will thus be heat
ed more at this point than at any other;
an unequal expansion takes place, the
scratch giving direction to the line. OF
fracture, and the tube cracks evenly if
its thickness is uniform In the case
of variable thickness uneven edges re-
suit, and these must be fled down to
avoid sharp, cutting splinters. Many
recipes and directions have been given
for cutting bottles. Wetting an ashes
tos string with turpentine and setting
it on fire produces considerable heat in
the glass Immediately underneath it.
By quickly removing the string and
pIunging the bottle into cool water the
unequal strain takes place and the
parts separate. 1t is this locating Oh
the heat that causes the glass to crack
as we wish it. The easiest method, il
the means be at hand, is to employ q
platinum wire, which should be heated
white hot by the passage of heavy
electric current. By wrapping the
wire round heavy bottle or jar and
allowing the current to pass for ten OF
fifteen seconds the stoutest walled YES
sci may be easily separated if touched
on the heated line with a cloth dipped
| in water