Flux-core welding
What thickness can you weld with flux-core welding?
Quick answer
Gasless flux-core handles 1.5 mm to 6 mm+ depending on machine class; it penetrates deeper than gas MIG at the same amps on thicker work.
Numbers by machine/output class
| Thickness | Wire | Current |
|---|---|---|
| 1.5–2 mm | 0.9 mm | 60–110 A |
| 3 mm | 0.9 mm | 110–150 A |
| 6 mm+ | 1.2 mm | 160–230 A |
Beyond single-pass
Thickness limits assume full-penetation single-pass welds. Bevelling the joint, multi-pass stacking and preheat on thick sections extend any process dramatically — that's how structural welders join 50 mm plate with the same physics. Match the machine class to the thickness you actually weld 90% of the time.