Troubleshooting

Why is my mig welding blow-through / burn-through?

Quick answer

Blow-through / burn-through in mig welding usually means too much current or too slow travel on thin sheet. For this process, drop amps and stitch weld before touching anything else.

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The specific fix

Drop amps and stitch weld. The general rule: drop amps, move faster, use skip welding, or tack tighter and stitch.

Process checklist

  • 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