OPERATION
Welding Techniques
After the operator has found the desired current, voltage, and electrode feed speed
settings for a particular application, it is still necessary to observe some element-
tary principles of technique.
Nozzle Spacing -
1.
In general, the gas nozzle should be held as close to the work as is practical.
In most cases, a distance of 3/8-inch to 5/8-inch is satisfactory.
Gun Angle -
2.
The best cleaning action is obtained, and excellent porosity-free welds are made
by using a forehand technique. For example, a horizontal fillet is best made by
the welding gun at an angle of 40 to 50 to the horizontal and using a forehand
angle of 20 to 25. A right-handed operator would then weld from right to left
on a horizontal weld.
Cleanness of Material -
3.
It is essential that aluminum be absolutely clean when it is welded. To ensure
porosity-free welds, a cleaning operation should immediately precede the welding
Several organic solvents are now available for this purpose.
operation.
4.
Wire Cleanness -
Wire should be clean and free from oxide, grease, and other foreign material. Do
not try to use wire that is not clean. Wire which is not in use should be kept
in a container which will protect it from all forms of contamination.
MAINTENANCE
Operating Maintenance -
As the gun is used, a small amount of spatter will collect on the end of the guide
tube and on the nozzle. This spatter can be removed easily with a knife or
similar implement. Periodically, remove the nozzle by pulling it from the nozzle hold-
er and inspect the nozzle and gun barrel for spatter which may have collected inside.
Excessive spatter can cause a short between the nozzle and the guide tube. Such a short
will create an arc between the nozzle and the workpiece if accidental contact is made.
If the guide tube becomes bent, replace it with a new guide tube. If a burn back occurs,
do not inch the wire. Attempts to inch the wire under these circumstances will blow the
fuses in the control circuit. When a burn back occurs, loosen the thumbscrew which se-
cures the guide tube, and inch both the wire and the guide tube out of the gun. Cut the
wire about 1/16" from the rear of the guide tube. Hold the guide tube perpendicular to
a hard, flat surface, and strike the end of the wire against the flat surface. If this
does not free the wire, cut or grind off the melted portion of the guide tube and remove
the wire. The burr caused by cutting should be removed from the guide tube hole with a
small drill. Failure to remove the burr can result in another burn back. Reinstall the
guide tube in the gun, ensuring that the end of the guide tube is the correct
