Safety Precautions - Continued
for hand protection.
Heavy, dark-colored clothing should be worn to prevent the ra-
diation penetrating to the skin or reflecting onto the neck under the helmet. Light
weight leather clothing Is recommended because of its durability and resistance to
deterioration from radiation. Cotton clothing will deteriorate rapidly when subject-
ed to ultra-violet radiation.
Adequate ventilation should be provided to remove fumes which are produced by this
welding process. American Standard Z-49.1 on welding safety covers such ventilation
Highly toxic gases are formed when the vapors from halogenated solvents
procedures.
are subjected to ultra-violet radiation. Therefore, It is recommended that degreas-
ers and other sources of these vapors should be located so that the vapors cannot
reach the welding operation.
Detailed safety precautions are given In the American Welding Society's publication
A6.1-55T, "Recommended Safe Practices for Inert-Gas Metal-Arc Welding".
GuideTube Position
Loosen the thumbscrew (5), and adjust the position of the guide tube until the end
of the guide tube is 1/8-inch behind the edge of the nozzle. When using 0.020 and
0.030-inch wires, the rear end of the guide tube must be back against the front
guide tube bushing to prevent the wire from buckling. With the rear end of an .020
or .030 guide tube (in the SP-10 Gun) positioned against the guide bushing, the front
end will be just even or slightly in front of the nozzle.
Wire Threading
Unscrew the knurled spool cover bolt, and remove the plastic cover. Pull back the ad-
justable brake (19), and place the desired spool of welding wire on the spool shaft so
that the free end of the wire will pay off from the top of the spool into the rear
guide bushing (7). Loosen the wire pressure screw (12) and open the swing arm (10).
Thread the free end of the wire Into the rear guide bushing, thru the front guide bush-
ing (6), and Into the wire guide tube (4). Close the swing arm (10) and adjust the
pressure screw until there is just sufficient pressure to prevent the wire from slip-
ping. Excessive pressure will overload the motor and cause erratic welding action.
Too little pressure will allow slippage and cause burn backs . Switcn the welder on
and pull the gun trigger (8). Since welding power still will be on when the trigger is
pulled, make sure the electrode does not touch the work ground as an arc will result.
If the wire has been threaded properly and the pressure screw is adjusted for the
correct pressure, the wire will feed freely from the guide tube. -
Brake Adjustment
Loosen the two screws which hold the brake support. Adjust the position of the brake
support by moving the screw in the slotted hole. Just enough pressure is applied to the
wire spool to prevent the wire from uncoiling.