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Lincoln Square Wave TIG Welders

Shop the Lincoln Square Wave TIG family — portable AC/DC TIG welders built for aluminum, stainless, and steel work in shops, schools, and home garages. The Square Wave TIG 200 and 205 deliver pulse, push-button start, and 200-amp output in a 50-pound portable package, making them the industry'’s most popular entry-level TIG machines.

TIG Welder FAQ

What is TIG welding?

TIG welding — formally Gas Tungsten Arc Welding (GTAW) — uses a non-consumable tungsten electrode to generate the arc while filler metal is added separately by hand, shielded by 100% argon gas. Because the electrode doesn't melt, the operator controls heat input, puddle size, and filler addition independently, making TIG the most precise common arc process. See the full TIG welder buyer's guide for AC/DC selection and model comparisons.

What is a TIG welder?

A TIG welder is a constant-current power source built for precise low-amperage GTAW output. DC-only machines weld steel, stainless, and most non-ferrous alloys; AC/DC machines add aluminum and magnesium capability. Professional inverter-based TIG welders add high-frequency arc start, pulse, and adjustable AC balance for fine aluminum control.

How do you TIG weld aluminum?

TIG welding aluminum requires AC output to break down the refractory oxide layer that forms on the surface before the arc can fuse the base metal. Use 100% argon shielding gas at 18–25 CFH, ER4043 or ER5356 TIG filler rod, and pure or 2% ceriated tungsten balled at the tip. Push the torch rather than dragging it, and preheat aluminum thicker than 3/16" to offset its high thermal conductivity.

Frequently Asked Questions

What is the difference between Square Wave TIG 200 and Square Wave 205?
The Square Wave 205 is the newer 2024 model — it adds digital pulse controls, a stronger 2T/4T trigger logic, and a refreshed shell. Output is similar (200 amps DC), but the 205 brings updated electronics, better aluminum AC waveforms, and improved value. The TIG 200 remains in the lineup as the entry-level option.
Can the Square Wave TIG weld aluminum?
Yes — both the 200 and 205 deliver true AC/DC TIG with high-frequency start and AC balance control, making them excellent aluminum welders. Pair with 100% argon shielding gas and a dedicated aluminum tungsten (pure or zirconiated) for best results.
Do Square Wave TIG welders include a torch?
Yes — both include a 17-series air-cooled TIG torch (12.5 ft.), foot pedal (Square Wave TIG 200 K5126-1) or finger amperage control, work clamp, ground cable, and gas hose. You'll need to add tungsten, filler rod, and an argon cylinder to start welding.
What input power does Square Wave TIG need?
Both models accept dual-voltage input (120V/230V single-phase) — you can plug into a standard 120V outlet for light work or 230V for full output. Output drops on 120V (limited to ~140 amps); 230V unlocks the full 200-amp rating.
Can I stick weld with the Square Wave TIG?
Yes — both models include stick (SMAW) capability with up to 200 amps DC stick output. Polarity switch lets you run DCEN (TIG) or DCEP (most stick rods) without rewiring.