Basics & process choice
AC or DC welding — what's the difference?
Quick answer
DC (direct current) runs nearly all MIG, stick and TIG steel/stainless welding — stabler arcs, easier starts. AC (alternating current) matters mainly for aluminium TIG (breaking up the oxide) and specific stick rods. 'AC/DC' on a machine's badge means it can do aluminium properly.
Polarity quick reference
| Process | Polarity | Why |
|---|---|---|
| MIG (gas) | DC electrode positive | heat into the wire and work |
| Gasless flux-core | DC electrode negative (usually) | check the wire packet — most want DCEN |
| Stick general | DC electrode positive | stability, penetration |
| TIG steel/stainless | DCEN | tungsten stays cool, work hot |
| TIG aluminium | AC | oxide cleaning + penetration each half-cycle |
Spot an error? Report it — corrections carry a dated note on our verification ledger.