Troubleshooting
Why does my weld have lack of fusion?
Quick answer
Lack of fusion is caused by too cold, too fast, or welding over mill scale without penetration. The fix: raise amps, slow travel, grind to bright metal, watch the wetting at the edges.
Root causes
Too cold, too fast, or welding over mill scale without penetration.
The fix sequence
- raise amps, slow travel, grind to bright metal, watch the wetting at the edges
- Change one variable at a time and re-test on scrap
- Re-inspect the finished bead — chisel, brush, look
When to grind it out
Structural or pressure work with visible defects: grind back to sound metal and re-weld — never 'cap over' a defect and hope. For non-critical jobs, judge honestly: a cosmetic defect is a learning note; a fusion or crack defect is a redo.