Spot welding
Common spot welding mistakes and how to fix them
Quick answer
The most common spot welding mistakes: electrode tips not dressed; too little clamping force: gap between sheets = no nugget; welding through paint or galvanising without adjusting current/time. Each traces to setup or technique basics — fix those first and the process behaves.
The usual suspects
- Electrode tips not dressed — dirty tips make weak, inconsistent nuggets
- Too little clamping force: gap between sheets = no nugget
- Welding through paint or galvanising without adjusting current/time
- Expecting one 240V handheld to do production battery-pack welds
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.