3.3 Welding Sheet Steel

Welding Sheet Steel

Because sheet metal is so thin, a MIG welder can’t produce a continuous weld bead without burning through the metal. No matter how much you dial down the voltage, you’ll burn through. But it can be done, if you know how. This video shows a couple of special welding techniques and equipment for working with sheet steel.

Video: Welding sheet steel



THIS PLUG-IN ELECTRIC SPOT WELDER IS NOT a MIG welder, BUT IT MAKES QUICK WORK OF JOINING THIN PIECES OF SHEET METAL.


Welding sheet metal with a spot welder

While you can do many welds on sheet metal with a MIG welder, there’s another welder I want to introduce, since it’s so well suited to sheet metal work. Spot welders are very useful and inexpensive devices, especially if you plan to weld sheet metal regularly. Spot welders pinch two or more layers of sheet metal in a pair of jaws and then deliver electricity through the jaw tips.

To use a spot welder, you place the metal between the jaws, close the jaws, then hit the on button. A shot of electric current travels through the jaws and the metal, joining the sheet metal in one small spot. It’s instant and requires no filler metal or fuss. Repeat the process along the joint every ½" to 1", and you’ve got a neat, strong connection that would be difficult or impossible to make with any other welder, even a MIG welder.

One useful and surprising feature of spot welders is that they work on more than just ferrous (iron-based) metal. For example, you can tack sheet copper parts together with the spot welder, then follow up and complete the joints with solder.