Troubleshooting
Why is my tig welding undercut?
Quick answer
Undercut in tig welding usually means too much heat or too fast travel at the weld toe — the parent metal gets washed away. For this process, less current, more filler at the edges before touching anything else.
The specific fix
Less current, more filler at the edges. The general rule: reduce current, slow slightly, adjust torch angle to fill the toe.
Process checklist
- Dipping the tungsten into the pool — contaminating the electrode and the weld
- Too much torch angle: 10–15° from vertical is plenty
- Forgetten post-flow gas: tungsten oxidises and turns black as it cools