Mill scale is the hard, dark oxide left on steel after it is hot-rolled. It looks like a thin black coating, but it is a poor welding surface. MIG welding…
Choosing MIG wire diameter for structural steel is mainly a balance between required weld size, steel thickness, welding position, and the output of your machine. A larger wire deposits metal…
Vertical-up fillet welds are slower and less forgiving than flat or horizontal welds, but MIG makes them manageable when the settings, gun angle, and travel speed are controlled. The goal…
The short answer For most solid MIG wire, set the machine to electrode positive (DCEP): the wire feeder’s torch connection is positive, and the work clamp is negative. For self-shielded…
MIG contact tip stickout is the distance from the end of the contact tip to the end of the welding wire. It is easy to confuse with the distance from…
Lap joints are one of the simplest MIG welding joints, but galvanized steel adds a serious complication: the zinc coating produces hazardous fumes when heated. Good results depend less on…
What porosity is—and why shielding gas matters Porosity is gas trapped in solidifying weld metal. It can show up as scattered pinholes, a line of pores, or a cavity exposed…
What birdnesting is Birdnesting is a tangle of MIG wire that piles up between the drive rolls and the gun liner instead of feeding through the gun. It usually happens…
Burn-through happens when the weld puddle melts through the sheet before you can move away or add enough metal to bridge the opening. The usual causes are too much heat…
Overhead MIG welding is difficult because gravity pulls the molten pool away from the joint. Too much heat or a slow travel speed can turn that pull into a hanging…