d. Remove Gun when gas flow stops. Use a wood
c. Flexible cable assembly locked to drive roll
stick to scrape inside of nozzle clean of any spatter ac-
cumulation. Do not bang nozzle.
d. Nozzle tight.
e. Place Gun aside where protruding wire elec-
trode cannot touch any metallic surface.
e. Welding wire protrudes from Gun nozzle.
3.5 SHUTDOWN PROCEDURES
3.3 PRELIMINARY PROCEDURES FOR GUN OPERATION
Environmental conditions and safety requirements will
determine the extent of equipment shutdown between
equipment has not been in
operations. If temperature may fall below the, freezing
recent use, point Gun toward floor
point, perform ALL the following steps, otherwise be-
and press trigger for a short inter-
gin with step e.
val to purge the gas and water lines.
a. Turn OFF welding power source.
Preset controls on equipment in the system as instruct-
ed in equipment manuals.
b. Turn OFF water and disconnect water supply
Whenever a new welding operation begins, perform a
c. Press Gun trigger to open water solenoid.
trial weld on metal similar to the workpiece. Proceed
d. Disconnect water-in hose and blow out water
lines with compressed air.
a. Clamp welding power source cable (negative)
to trial piece.
e. Place all (remaining) power controls OFF.
b. Aim Gun at trial piece to be welded, holding
f. Disconnect power cable from the 115 volt ac
nozzle a few inches away.
g. Turn OFF gas.
c. If operation is set for SCRATCH START, rub
the sharp end of welding wire against trial piece until
h. Place Gun in safe location. Coil or drape hose
arc is started; if set for RUN-IN START, arc should
and cables without sharp bends.
start as soon as welding wire contacts trial piece.
d. When arc starts and gas flows, vary distance
3.6 PRINCIPLES OF OPERATION
of Gun nozzle from trial piece to determine approxi-
mately how far from trial piece Gun operation pro-
When the Gun trigger switch is closed, it operates a
duces the best results.
main control relay which, through other relays, com-
pletes the circuits to the weld current, gas and water
e. Release trigger but hold Gun over weld puddle
solenoids, water pressure switch, and time-delay re-
until post-weld gas flow stops.
lay (which provides a timed interval of post-weld gas
flow). Simultaneously, a motor-drive relay circuit is
f. Set Gun aside where protruding wire electrode
energized to run the feeder motor. This motor, drives
cannot touch any metallic surface.
a wormshaft through the flexible shaft within the drive
roll housing locked to the Gun.
The wormshaft, in turn, drives a geared shaft on each
3.4 WELDING OPERATION
side, which turn in opposite directions. One shaft end
contains a grooved roll fitting in which the welding wire
To perform a welding operation with the Gun, proceed
is seated; the other contains a conical roll which pro-
vides pressure against the wire in the grooved roll.
Hence, the welding wire is pulled through the Gun cas-
a. Aim Gun at workpiece. Keep nozzle at distance
ing from a spool in the feeder.
found satisfactory during trial weld.
Welding current from the welding power source is ap-
b. Pull back and hold trigger to keep wire feeding
plied to the system through a reverse polarity circuit.
continuously into arc. (Weld puddle will be protected
This consists of a secondary weld contactor (if needed),
by shielding gas as puddle solidifies. )
a welding current cable attached to the Gun barrel, the
welding wire (consumable electrode) within the barrel,
c. Release trigger to stop welding, but hold Gun
the workpiece, and the cable from the power source
in same position for short interval until post-weld gas
clamped to the workpiece.