Evening star., 1937-08-14
GOTHAM To ALLOW
WELDED BUILDINGS
Last Big Obstacle to Use of
"Hot Snakes" Removed
in Code Chanqe.
BY HOWARD w. BLAKESLEE.

BY HOWARD w. BLAKESLEE.
NEW YORK, August IA (P).-The
''hot snakes" of the Machine Age, the
electric welding rods have beaten the
last big obstacle to use of welding Of
buildings
This was the New York City build
ing code, which forbade the welding
in the worlds skyscraper capital
After January ! next the code will
permit welding to substitute for riv-
citing
The change is not simply recogni-
ton of the march of science 1t is
tribute to the skill of workmen who
handle hot snakes" Helmeted and
eauntleted like futuristic monsters,
holding rod hotter than many types
of stars, these men combine the skill
In touch of a sculptor and a goldsmith
The rod is slender steel. never more
than a quarter inch in diameter
usually an eighth or A sixteenth
Through it flows the welding current
$50 to 300 amperes and 30 volts.
Arc Must Be Struck.
play on the spot to be welded This
arc won't start. until the rod tip first
touches the steel to be welded and is
withdrawn. That is called striking"
the arc. But the trick is nothing as
crude as striking
For If the live tip touches even as
long as it takes to dot this letter Il >"
IT. sticks fast, It gets red hot and
writhes like Aaron's rod which was
cast down.
The touch may last only a fra ction
of second. In that instant, if the
tip Of the rod be withdrawn ever so
slightly, the arc will start. The skilled
Welder accomplishes this by barely
scratching the rod point on the steel
to be welded. The tip is moved cross
wise
With the arc going, the tip of the
rod must be held within an eighth to
3 sixteenth of an inch from the weld
The tip is boiling with heat of $500
degrees Fahrenheit This is hotter
than the surface of many stars. Glob-
ules of liquid steel drip from the tip.
IouCn mDSt NOT NaVer.
They shorten the rod They force
the welder to press the tip always
closer to keep the gap uniform. If
his touch Wavers and the tip contacts
the steel hot snake" will writhe in
his grasp.
If he errs in the other direction.
and gets more than an eighth of an
inch away, his rod hisses. This is the
sound of imperfect welding. At the
right distance the Juice" and the
melting steel crackle.
The cracking is the sound when
the heat of an electric arc is pene-
fratlng the right depth. 1t melts the
steel of the parts to be welded. They
flow together, along with the steel
dripping from the mouth Of the hot
snake"
1t is possible for this newly mixed
steel to be stronger, after cooling,
than the original parts. The welded
JOINT then can stand unharmed q
strain that bends the parts. But. if
the workman's hand is unsteady it is
also possible for the weld to be weak.
Science, which has placed so much
responsibility for safety on a human
hand, has also devised X-rav eyes
which Will look through the steel welds
10 see that the work was well done.
X-Ravs Used in Examination,
One of the newest of these eyes re-
sembles miniature automobile trail
er. 1t is towed by an auto from Job
to job. It's oval roof is q field dark
room. It's eye is fat grid plate on
the end of long, flexible cable This
eve moves about like the head of a
long serpent. The grid is placed on
the weld to be looked at On the op-
posite side of the weld is a photo
graphic plate. Electric current flows
through the cable and produces X-rays
In the grid
In one minute these rays can photo
graph through inches of steel.
Herbert R. Isenbereer of Brooklyn.
president of the company which oper-
ates this X-ray system says:
Our experience on one of the last
Jobs was that the welders made very
poor joints in the beginning, and only
after they had seen the X-ray results
were they able to correct their tech
nlque. The fact that the X-ray ma
chine is available on the job has an
excellent effect on the welders"
There are machines which do au-
tomato Welding The places where
they can be used at present are COM
paratively few. Gas, usually an oxy-
scetelyne fame, will weld the same as
an electric arc, But the hot snake
Is at present more generally used.
Welded Buildings Recent.
The welding arc itself goes back
many years. 1t was one of the first
uses of electric power. But the weld
ing of buildings goes back only to 1920
In that year and in 1919 four stee
building were made by welding. Ont
was a small industrial building ir
Brooklyn. Three others were built il
England
Soon tfe public was told that the
din Of Tiveting might be a thing o
the past. But engineers and archi.
tecs demanded proof of safety. Fol
years, u metallurgical laboratories
YIELDS ~ all sorts were whirled
stretched snd bent to death" TIL,
kind of weld which would be SAT-
was established beyond REASONABLE
doubt