Flux-core welding
Common flux-core welding mistakes and how to fix them
Quick answer
The most common flux-core welding mistakes: wrong polarity; dragging the gun like stick; leaving slag-capped wormholes by welding too slow or too hot. Each traces to setup or technique basics — fix those first and the process behaves.
The usual suspects
- Wrong polarity — most gasless wire wants DCEN (electrode negative); check the packet
- Dragging the gun like stick — gasless likes a slight drag angle, unlike gas MIG
- Leaving slag-capped wormholes by welding too slow or too hot
- Chipping slag cold and rushing — it comes off easier while still warm
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.