How to Successfully MIG Weld Aluminum
toyota1515 > 07-12-2022, 08:56 AM
Keep in mind these important factors when MIG welding aluminum for your application.
Tips for getting started
Consider material thickness: Material thicknesses of aluminum that can be MIG welded are 14 gauge and heavier; the output capacity of your welder determines the thickness you can weld. To MIG weld aluminum thinner than 14 gauge (.074 inch), it may be necessary to use specialized pulsed MIG or AC TIG welding equipment.
Keep it clean: Aluminum should be thoroughly cleaned prior to welding, including the removal of any lubricants from the material. Oxide removal should be done after degreasing using a stainless wire brush — either a hand wire brush or a cup wire brush will work. If a power wire brush is used, keep the rpms and pressures low to reduce smearing the surface of the material, which could entrap oxides and impurities under the surface. To avoid contaminating the base material, always clean with a wire brush that is used on aluminum only.
Choose the right gas: Because aluminum is a non-ferrous metal, it requires a 100 percent argon shielding gas. Flow rates of 20 to 30 cubic feet per hour are recommended.
What process should you use? When MIG welding aluminum, the desired mode is spray transfer. This process is a very smooth transfer of molten metal droplets from the end of the electrode to the molten pool. The droplets crossing the arc are smaller in diameter than the electrode. There is no short-circuiting in spray transfer, and the deposition rate and efficiency are relatively high. However, be aware that spray transfer involves a high amount of heat, creating a large weld pool with good penetration that can be difficult to control. It should not be used on materials thinner than 14 gauge.
Gun and wire feeding options: Choosing a gun and wire feeding system is an important step before MIG welding aluminum. Aluminum wire is commonly fed with a spool gun or with a push-pull system. Spool guns improve feeding of soft wires by locating a small pool of wire on a pistol-grip style gun. Using a spool gun eliminates the possibility of birdnesting because the wire only feeds a few inches. With a push-pull system, a motor in the gun pulls the wire through the liner, while a motor on the feeder acts as an assist motor. This option is ideal when welding far from the power source and can be more ergonomic and user-friendly.