How to MIG Weld Sheet Metal
Posted: June 9, 2017 By: MattM
When you’re first starting out MIG welding it can be a difficult road to getting comfortable enough to weld something delicate that you don’t want to mess up. Most beginners start on fairly thick, flat plate. We suggest starting with 1/8″-3/16″ to allow you some room for error when welding. The problem with welding sheet metal or thin gauge steel is that you can easily blow holes in the panel and create a big mess quickly. We decided to give you some tips when welding sheet metal and help you get jump started.
- Infinite Adjustability- If you don’t have a MIG welder yet we suggest looking for a machine that has infinite adjustability. This means that wire feed and power or voltage adjustment can be moved in almost any configuration to weld. This allows you to really dial the machine in for thinner metal or uneven metal thicknesses. Preset settings are nice on some welders, but often times you’ll find yourself needing to be in between a setting to get the best weld. All Eastwood welders come with infinite adjustability allowing you to get the perfect weld on your project.
- Practice Makes Perfect- Whether you’re a seasoned veteran or a beginner welder it is good to set your MIG welder up on a scrap piece of metal the same thickness as what you want to weld. This will leave you some room for error if you need to practice or set the machine up. This will save burning holes in a panel and then having to try and fill or repair the damage you created!
- Short, Quick Welds- When welding sheet metal with a MIG welder you do NOT want to try and run one long bead like when you’re welding heavier metal. Sheet metal warps easily and also can burn through easily. When welding a long bead on sheet metal you’ll put excessive heat into the panel and run the risk of the puddle falling through the panel. A better technique is to move around the weld seam doing short, quick stitch welds that you eventually connect all together. For reduced warping we suggest stopping periodically and letting the panel cool once it is hot to the touch a few inches away from the weld seam.
- Use thin wire- One big mistake we see with beginners is using welding wire that is too thick for the metal they’re welding. If your welding wire is too thick it will take more heat to melt the wire than the substrate and can make it even more prone to blowing holes in the panel. For thinner gauge sheet metal like 18 or 20 gauge we suggest .023 (6mm) wire in your MIG welder.
- Keep the Stick Out Short- Stickout of your MIG wire is important when welding any type of metal, but especially sheet metal. Holding the tip too far from the surface will cause the wire to have to come out too far to touch the metal. This means the extra wire causes the voltage to drop by the time it actually gets to the surface and strikes an arc. This drops the voltage and heat of the weld arc and causes the welds to sit proud (no penetration) on top of the metal. The other problem with excessive stick out is that the shielding gas is coming out further from the surface and can drift away from, or never make it to the weld puddle. This causes pits or imperfections in the weld that make a weak weld. Ideally keep the tip of the welding wire about 1/16″ from the surface before hitting the trigger. This will keep you far enough away from the weld puddle, but give the least resistance for the arc when welding.
If you stick to these tips when setting yourself up for MIG welding sheet metal you will be much more confident and successful. For affordable, quality MIG welders check our entire welding line out here: https://www.eastwood.com/welders/mig-welders.html