Shenandoah herald. [volume] (Woodstock, Va.) 1865-1974, 1913-06-06
A Knife of Flame.

One of the most curious instrr
ments used by the structural iro
workers and steel shipbnilders
the most astonishing in its per
Torrance and the most spectac
ular when seen at work, is tn
exyacetylene torch. 1t is mad,
in two forms-a welding torch
and 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
thickness, the heaviest weld of
| which there is any record being
fourteen inches.
With the cutting torch steel
and iron (other than cast iron)
are readily cut, with the aid of
mechanical devices for guiding
the torch, up to a thickness OF
eight or nine inches, This means
that with the oxyacety1ene 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 kerr in
cutting the steel-that is the
part of the metal that is burned
away where the cut is made-is
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 minutes.
To the man who knows MOTH
lug of chemistry or what actual
ly takes place when any object
burns this seems incredible.
When the process of combustion
is explained the mystery is swept
away. Combustion, then, in its
simplest terms, consists in rails
ing the temperature of an object
to point where it will unite
chemically with the oxygen of
The air. When this chemical ac-
ton takes place it is accompa MED
by light and heat, and the OBJ
ject is said to burn"
This temperature varies great
1y with different objects or sub
stances. Many substances that
burn at a comparatively low
temperature can be set on fire
with a match. With these SUBJ
stances every one is familiar, and
other substances that will not
readily burn when a match is ap-
piled to them are propularly re-
garded as "firepfoof."
But this is a wrong view. 1t
may simply mean that the tenn
perature at which the object will
burn-called the "kindling tenn
perature"-is too high to be
reached by the burning match.
This is the case with iron and
steel, and when the oxyacetylene
flame cuts through a bar of steel
nine inches thick and three feet
wide it simply burns up a layer
of the metal one-eighth of an
inch in thickness.
The welding torch, to describe
it as simply as possible, consists
of handle through which ex-
tend two tubes of brass. These
tubes are connected with two
gas tanks, one containing OK
ygen and the other acetylene, and
these gases are admitted to the
| tubes by valves at the rear, the
oxygen entering the upper tube
and the caetylene the lower.
Both tubes open into the head of
the torch into which is screwed a
nozzle or tip. The gases enter
this tip by separate passages and
are there mixed together and
being under pressure. and spurt-
ed from the jet. The acetylene
is first turned on and lighted.
This is the full of the flame. Then
the oxygen is turned on. This
supports the flame.
The quantity of each gas can
! be regulated by the valves, and
thus there is produced what is
called "a neutral f1ame"-this
is to say, it contains neither al
excess of oxygen nor of acetylene
, but just enough of each to &C
complish complete combustion
The temperature produced by thi
flame, with an almost pencil
point concentration, is approx