When electric welding was perfected it was clearly a game changer, but it took a few years for MIG welding machines to become small and affordable enough to be practical for hobbyists and small shops. Today, you can get machines not much larger than a bread box that have all the power you need for any truck project.
The beauty of the MIG process is that it’s very easy to learn. You simply point the tip of the gun where you want to make a weld, pull the trigger, and the gun initiates the welding current and the flow of shielding gas, feeding the filler wire automatically. When you release the trigger, the weld stops immediately. It’s almost as easy as using a caulking gun!
MIG machines use spools of filler wire, usually housed inside the case of the machine. Many machines can be fitted with either 1- or 10-pound spools. There are several wire sizes that can be used for automotive work, but 0.030-inch wire works fairly well for most applications. If you are welding mostly on sheetmetal, 0.023-inch wire might be a little easier to control. While flux-cored wire is used for some industrial applications, most truck builders prefer solid wire, although it requires a gas shield.
When preparing to weld, one of the most essential steps is selecting the correct wire feed speed, and voltage. Nearly all machines come with a chart (often inside a hinged cover), giving you the recommended settings based on the thickness of the metal you’re welding and the filler wire diameter. Many experienced welders tweak these adjustments, going by the look of the weld bead and the sound of the arc, but everyone needs to know where to start. Miller pioneered a feature on their welders called Auto-Set, which really simplifies adjusting the parameters. You dial in the diameter of the filler wire, and the thickness of the metal being welded—that’s it!
The key to getting strong, good-looking welds is mastering your torch technique. Small changes in the torch angle, travel speed, and the distance from the gun to the work piece will have a big effect on your results. The only way to master your torch technique is through practice. The more you practice, the quicker you’ll get consistent results. Remember, even the people who are pros now were once beginners.
All welding processes require attention to safe operating procedures. We don’t have space here to cover safety comprehensively, but it’s essential that every welder inform themselves with the dos and don’ts before they start.