TIG welding equipment

DC or AC/DC — the first decision

This is the single biggest fork in choosing a TIG machine. DC-only covers mild steel, stainless steel, copper and chrome moly — cheaper, simpler, and enough for most fabrication and repair work that doesn't involve aluminium. AC/DC is required for aluminium: the AC current breaks down aluminium's oxide layer, which DC can't do. If aluminium is anywhere in your work, buy AC/DC from the start rather than upgrading later.

Choosing tungsten and filler rod

Tungsten type depends on what you're welding: DC work on steel and stainless typically runs lanthanated or thoriated tungsten; AC work on aluminium needs zirconiated or a rare-earth blend rated for both. Electrode diameter scales with amperage — too small for the current and the tip breaks down mid-weld.

Filler rod must match the parent metal — dissimilar filler and base metal won't weld properly. Rod classification matters too: for example, marine-grade stainless work calls for a low-carbon rod rated for corrosion resistance.

Gas flow for TIG is lower and more precise than MIG — set to the cup size you're running, not a single blanket number.

Amperage — a starting point, not a formula

There's no single chart that says "this thickness needs this many amps" — joint type, tungsten size, welding position and technique all move the number. As a rough starting point: stainless generally runs slightly lower amperage than mild steel at the same thickness, and aluminium needs more amperage than either to overcome its oxide layer and higher heat conductivity. Treat any amperage chart as a starting point to dial in from, not a fixed setting.

Common questions