If thickness is less than 3 mm (0.12 in): There is no need to chamfer the edges of the plates. Butt the work pieces together without a gap.
If thickness is more than 3 mm (0.12 in):
Use a disk grinder, or course file (rough, vixen file) to make a V-groove, or chamfer, along the mating line (V-shape grooving).
Smooth the ground surface using a disk sander (P80) or fine file.
With a V-groove, back beads are easily formed.
When thickness is 3 mm (0.12 in) or less:
When thickness is 3 mm (0.12 in) or more:
2.
Cleaning and removal of oxidized layer:
Remove contamination and oil content from the area to be welded using degreaser.
Sand off paint film using a disk sander (P80).
Remove the oxidized layer using a stainless wire brush.
Remove oxidized layer from the hatched areas.
3.
Tack welding:
Basically same as the welding of steel panels. Tack welding is required to reduce distortion for precision of the welded joint.
Weld short beads at several places. The thinner the panel, the smaller the welding pitch. Do not weld the end or corner of the work piece.
FORWARD WELDING
4.
Main welding:
Clean the welding area with a stainless wire brush just before welding.
Hold and tilt the torch 5 to 15 degrees then weld along the mating line and use a push or forward welding technique.
While checking the tip-to-work clearance, torch angle and penetration, adjust torch feed speed.
As your welding skill improves, you can increase the torch feed speed using high power (current). Such quick welding reduces heat transfer into the work and minimizes distortion.
When welding thin panels, burn through can be prevented by using a skip or stitch welding technique.
If the welding equipment has a stitch mode, use it for stitch welding.
5.
Filling a crater:
Stop the torch once you reach the end of welding bead and fill in the crater.
Stop and start the arc repeatedly to fill up a crater that occurs at the end of a welding bead.
6.
Distortion-free welding Similar to welding steel panels, a large distortion occurs when excessive heat is applied to aluminum alloy work pieces. The thinner the panel, the more distortion occurs. Refer to the steel panel welding for tips on distortion-free welding.
