Troubleshooting
Why is my mig welding lack of fusion?
Quick answer
Lack of fusion in mig welding usually means too cold, too fast, or welding over mill scale without penetration. For this process, raise amps and grind to bright metal before touching anything else.
The specific fix
Raise amps and grind to bright metal. The general rule: raise amps, slow travel, grind to bright metal, watch the wetting at the edges.
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