Steve Martin had a bit that was like a fake infomercial where he says, “You can be a millionaire and never pay taxes!” The instructions were, “First, get a million dollars. Then,…” [Brandon’s] instructions for how to convert your MIG welder to do aluminum for under $25 is not quite like that, but you do need the right kind of MIG welder to make it work. In particular, you need an actual MIG welder that has a provision to connect external gas. The instructions show a Hobart Handler 140 that meets the criteria and has sufficient power to handle aluminum.
The main task is to replace the liner for the torch. The stock liner is steel which is fine for its intended purpose, but it is too rough for aluminum wire. A PTFE liner is inexpensive and will work fine with the aluminum wire. If you want to do normal welding later, you’ll need to put the original liner back in.
The other thing you’ll need is argon gas and the welder needs to be configured for solid wire and gas. The chart in the welder shows that you can use it for aluminum, but it does mention that it is difficult to feed with the stock liner.
Aluminum wire expands as it heats, so you need a slightly larger tip than the wire size. For example, in the video, [Brandon] uses .030″ wire and a .035″ tip. The relatively low amperage and duty cycle of the welder mean you need a small wire size.
Did it work? It did. He did preheat the work to help the small welder get the workpiece to temperature. It took a little experimenting to get the right angles and technique. In the end, he points out some of the benefits of having a machine meant to weld aluminum. However, for occasional use, this seems like a practical modification.
Sometimes welding takes a big bang. We don’t know how to create our own argon, but we did see someone make their own carbon dioxide shield gas, not long ago.