Miller Electric

If you already own a MIG welder, you may be wondering what it takes to start using that machine to weld some aluminum. Miller® has continued to provide spool gun solutions that are simple and directly connect to your welder for welding aluminum. This makes changing to aluminum faster and less expensive than you may think.

First, you’re going to need a spool gun. Why another gun? Well, the column strength or the amount you can push on Aluminum wire without buckling is only about one-third the amount that mild steel wire can withstand. This causes feeding issues if you try to push the aluminum through a standard MIG torch. Spool guns only push the wire a short distance in a straight line from the drive rolls, so feeding isn’t compromised. The Spoolmate™ 100 Series spool gun is a direct connect option for the Millermatic^® 140 Auto-Set™, 180 Auto-Set and 211 Auto-Set with MVP MIG welders, and the Multimatic™ 200 MIG/TIG/Stick welder. The Spoolmate™ 200 Series spool gun is the entry level spool gun for the Millermatic 212 Auto-Set and Millermatic 252 MIG welders. For the more industrial user, the Spoolmatic^® 15A or 30A guns are a better fit on those machines.

The next thing you’re going to need is different shielding gas. Aluminum requires 100 percent argon shielding gas. Any shielding gas containing oxygen will cause an unstable arc with impurities when welding Aluminum.

Finally, you will need to be sure you have good MIG welding technique.  Aluminum requires you to push the torch to ensure effective shielding gas coverage. Everything else in your technique is the same as welding mild steel, but at a faster pace. Due to the high thermal properties of Aluminum, more heat is required to start a molten puddle. This increased amount of heat then requires a higher travel speed once the puddle is established to prevent burn through. Aluminum MIG welding doesn’t have to be difficult with the appropriate equipment and some practice.

In this video, I used a Diversion™ 180 TIG welder to create an aluminum air pan for a ’48 F1 Ford pickup truck. In this video, you’ll see that I also demonstrate how to weld with different material thicknesses. As always, make sure you start with clean material. I am using 5356 aluminum filler for this particular project, but cut it in half for easier use. When you’re welding with materials with different thicknesses, the Diversion™ 180 is an ideal welder for the DIYer because of its ability to let you easily dial in the material type and thickness on the machine. When working with thinner aluminum material, consider skipping welds to prevent warpage and evenly distribute the heat. An example of skip welding would be making a one-in weld and then skipping six-inches before making the next one-in weld. When skip welding, try using silicone filler to create a better seal. Another tip to remember when using different material thicknesses is to preheat. In this video, the ½-in plate is outside maximum capability of machine. To get around it, preheat the thicker material to make it easier for puddle to wet out.

John Swartz
TIG Commercial Product Manager