Its Repair is challenging and its use is spreading.
Aluminum is making new demands on skills and equipment at every shop. By Bob Jansen, Contributing EditorSelecting A GMA (MIG)
Wire Feeder System
A push feeder is similar to what is used for most steel GMA (MIG) welding. A variable speed motor pushes wire through the liner to the gun. With push feeders, the liner length must usually be limited to about 3 meters (10 ft.). Aluminum electrode wire tends to buckle and bind at the drive rolls when using long liners with a push feeder. This can cause birdnesting. A push feeder may not work well for feeding the small diameter electrode wires required for some exterior body panels, especially a soft electrode like 4043. An advantage of a push feeder is the small size of the gun for access to most areas.A push-pull feeder has two motors and two sets of drive rolls. One set of each is in the power source cabinet and the welding gun. This provides uniform feeding for small diameter electrode wire. Soft electrode wire, such as 4043, can also be used with no problems. A push-pull feeder can have a liner more than 9 m (30 ft.) long. A possible disadvantage is the complexity of this type of feeder system, sometimes requiring a separate feed cabinet.A spool gun feeding system is common on GMA (MIG) welding machines set up for aluminum. A spool gun has a small spool of electrode wire, usually 100 mm (4 in.) in diameter, attached directly to the welding gun. The spool weighs about .45 kg (1 lb). There is a motor and drive roll set and a short gun liner also contained on the gun. The short gun liner allows the feeding of 4043 electrode and the use of knurled drive rolls without a problem. There is virtually no limit to the length of cable from the gun to the power source, since the electrode wire is not being fed through it. Another advantage of a spool gun is that because the feeder system is contained in the gun, a GMA (MIG) welding machine can be set up for both steel and aluminum at the same time. One possible disadvantage is that a spool gun may have limited access to welding areas due to its size. Also, the small size of the spool gun means more frequent changes.
A push feeder is similar to what is used for most steel GMA (MIG) welding. A variable speed motor pushes wire through the liner to the gun. With push feeders, the liner length must usually be limited to about 3 meters (10 ft.). Aluminum electrode wire tends to buckle and bind at the drive rolls when using long liners with a push feeder. This can cause birdnesting. A push feeder may not work well for feeding the small diameter electrode wires required for some exterior body panels, especially a soft electrode like 4043. An advantage of a push feeder is the small size of the gun for access to most areas.A push-pull feeder has two motors and two sets of drive rolls. One set of each is in the power source cabinet and the welding gun. This provides uniform feeding for small diameter electrode wire. Soft electrode wire, such as 4043, can also be used with no problems. A push-pull feeder can have a liner more than 9 m (30 ft.) long. A possible disadvantage is the complexity of this type of feeder system, sometimes requiring a separate feed cabinet.A spool gun feeding system is common on GMA (MIG) welding machines set up for aluminum. A spool gun has a small spool of electrode wire, usually 100 mm (4 in.) in diameter, attached directly to the welding gun. The spool weighs about .45 kg (1 lb). There is a motor and drive roll set and a short gun liner also contained on the gun. The short gun liner allows the feeding of 4043 electrode and the use of knurled drive rolls without a problem. There is virtually no limit to the length of cable from the gun to the power source, since the electrode wire is not being fed through it. Another advantage of a spool gun is that because the feeder system is contained in the gun, a GMA (MIG) welding machine can be set up for both steel and aluminum at the same time. One possible disadvantage is that a spool gun may have limited access to welding areas due to its size. Also, the small size of the spool gun means more frequent changes.
Store GTA (TIG) filler
rods and GMA (MIG) electrode wire in airtight plastic bags to prevent
moisture contamination. They should also be stored at room temperature.
Except on spool guns,
knurled drive rolls are not used when welding aluminum as they can shave
off the electrode wire creating flakes of aluminum oxide that collect in
feed areas, causing arcing and binding in the contact tip.
This contact tip, stamped
