Shepherdstown register. [volume] (Shepherdstown, Va. [W. Va.]) 1849-1955, 1913-04-24
Jefferson nComyW "a, 1913
A Knife of Flame.

A Knife of Flame.
One of the most curious instruments
used by the structural iron workers and
steel shipbuildeTs, the most astonishing
in its performance and the most spectac-
ular when seen at work, is the oXYacety-
lene torch. II is made in two forms-a
welding torch and a cutting torch. With
the former cast iron, cast steel, steel,
wrought iron, aluminium, brass, copper,
platinum and various alloys can be welded
with ease, while perfect weld can also
be made between any combination OF
cast iron, steel, brass and copper. Yields
are often made in steel and iron with this
torch up to eight and nine inches in thick
ness, the heaviest weld OF which there is
any record being fourteen inches.
With the cutting torch steel and iron
(other than cast from are readily cut,
with the aid OF mechanical devices for
guiding the torch, up to thickness OF
eight or nine inches. This means that
with the oxyacetylene torch a piece OF
steel eight or nine inches thick and OF
any width can be cut squarely in two,
just as a carpenter saws through board
or a beam. The kerf in cutting the steel
that is the part of the metal that is
burned away where the cut is made-lS
only about one-eighth OF an inch wide.
Steel six inches thick can be cut in this
way at the rate OF one foot in three min
uteS.
To the man who knows nothing OF
chemistry or what actually takes place
when any object burns this seems in
credible. When the process OF combus-
ton is explained the mystery is swept
away. Combustion, then, in its SIM
plest terms, consists in raising the tenn
perature OF an object to point where it
will unite chemically with the oxygen OF
the air. When this chemical action takes
place it is accompanied by light and heat,
and the object is said to burn"
This temperature varies greatly with
different objects or substances. Many
substances that burn at comparatively
low temperature can be set on fire with
match. With these substances every one
is familiar, and other substances that will
not readily burn when match is applied
to them are popularity regarded as "fire-
proof"
But this is a wrong view. II may SIM
ply mean that the temperature at which
the object will burn-called the "kindllng
temperature"-IS too high to be reached
by the burning match. This is the case
with iron and steel, and when the OK
yacetylene flame cuts through bar OF
steel nine inches thick and three feet wide
ii simply burns up layer OF the metal
one e-eighth OF an inch in thickness.
The welding torch, to describe it as
simply as possible, consists OF a handle
through which extend two tubes Of brass.
These tubes are connected with two gas
tanks, one containing oxygen and the
other acetylene, and these gases are ad-
mtted to the tubes by valves at the rear,
the oxygen entering the upper tube and
the acetylene the lower. Both tubes
open into the head OF the torch into which
is screwed nozzle or tip. The gases
enter this tip by separate passages and
are there mixed together and beingunder
pressure, are spurted from the jet. The
acetylene is first turned on and lighted.
This is the fuel of the flame. Then the
oxygen is turned on. This supports the
flame.
The quantity OF each gas can be reg
ulated by the valves, and thus there is
produced what is called "neutral flame
that is TO say, il contains neither an ex-
cess OF oxygen nor of acetylene, but just
enough OF each TO accomplish complete
combustion. The temperature produced
by this flame, with an almost pencil point
concentration, is approximately $500 de-
greeS F.
In the cutting torch there is a difference
in construction, because the object now
is not only to heat the metal, but also to
burn ito consume it by fire. The torch
is so made, therefore, that at first "pre-
heating" flame, which is the same as the
welding flame, is directed against the
metal, its purpose being to heat the metal
to incandescence, or "white heat" When
this point is reached a Slight movement
of the thumb on the hand holding the
tor.h opens valve that sends rushing
against the hot metal separate stream
OF oxygen under high pressure.
At its great heat OF $500 degrees and
in the presence OF this free oxygen the
metal readily burns. The iron or steel
is the fuel, and the stream Of oxygen sup
ports the combustion.
The cutting torch is now used in the
repair Of ships in many ways. A new
ventilator hole, portfolio, piece Of DAM
aged deck or side plating can be cut out
and removed in a few minutes. Very
often when new boilers are to be installed
in vessel the old ones are cut into pieces
with the torch and removed in few
hours.
Some fellows don't care what they say,
and neither does anybody else.