MIG welding
Common mig welding mistakes and how to fix them
Quick answer
The most common mig welding mistakes: stick-out too long; travel too slow on thin sheet, burning holes instead of building a bead; wrong wire size for the job. Each traces to setup or technique basics — fix those first and the process behaves.
The usual suspects
- Stick-out too long — keep 8–10 mm from nozzle to work for a stable arc
- Travel too slow on thin sheet, burning holes instead of building a bead
- Wrong wire size for the job — 0.9 mm covers most hobby work in Australia
- Gas off or breeze blowing the shield away — porosity is a gas problem 9 times out of 10
Diagnose from the bead
Your weld bead is a data readout: undercut says too hot or too fast, humpy ropey beads say too slow or too cold, spatter says voltage mismatch or stick-out, porosity says shielding. Chisel, brush and read every practice bead before you blame the machine — 90% of 'machine problems' are settings problems.