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The Lincoln Square Wave 205 (K5613-1) is Lincoln Electric's flagship portable AC/DC TIG and Stick welder, replacing the legendary Square Wave TIG 200 with a 5-amp bump to 205 A, a full-color 4.3" LCD interface, and advanced waveform controls that were previously found only on machines costing two to three times as much. If you weld aluminum, stainless, mild steel, or chrome-moly — and you want professional results from a 36-pound machine you can carry to any outlet — this is the welder.
- AC/DC TIG and Stick in one machine. AC TIG on aluminum and magnesium, DC TIG on stainless, steel, chrome-moly, and titanium — plus dedicated E6010 and E7018 DC Stick modes with crisp or soft arc selection.
- True dual-voltage: 120 V or 230 V without any adapter rewiring. Auto-sensing input detects the outlet and optimizes output. Use 120 V for light sheet metal and low-amp work; switch to 230 V for full 205 A TIG output on aluminum up to 3/8" and steel up to 1/2".
- Advanced pulse TIG built-in. Pulse frequency from 0.1 Hz to 500 Hz (on 230 V). Low-frequency pulse (0.5–2 Hz) helps beginners control the puddle on thin stainless; high-frequency pulse (above 100 Hz) creates a focused, tight arc cone on 1/8" and thicker material without adding heat to the surrounding zone.
- AC frequency and AC balance control. Adjust AC frequency from 60–150 Hz: lower frequency for more cleaning on heavily oxidized aluminum, higher frequency for a more focused arc and narrower bead width. AC balance (60–90%) controls the oxide-cleaning vs. penetration ratio — critical for consistent aluminum TIG welds.
- 4.3" full-color LCD. Multilingual (English, Spanish, French). Built-in parameter guide shows recommended amperage, tungsten size, and filler for selected material and thickness. Guides beginners and speeds up setup for experienced welders switching materials.
- High-frequency arc start and lift TIG start. Touchless HF start eliminates tungsten contamination and produces consistent arc initiation at low amperages. Lift TIG available for environments where HF interference is a concern.
- Ships complete. Everything to start welding except filler metal and gas cylinder: Premium Caliber TIG torch with flexible head (12.5 ft), foot Amptrol (25 ft), gas regulator/flowmeter, work cable and clamp, electrode holder, and a TIG kit with gas lenses, tungsten electrodes (0.040" to 3/32"), and collets.
- 3-year factory warranty. Lincoln Electric's full 3-year warranty on all new K-prefix units.
| SKU / Model | K5613-1 / Square Wave 205 |
| Processes | AC TIG (GTAW), DC TIG (GTAW), DC Stick (SMAW), AC Stick (SMAW) |
| Input Voltage | 120 V or 230 V, 1-Phase, 50/60 Hz (auto-sensing) |
| Input Current | 120 V: 25 A | 230 V: 22 A |
| Output Range — TIG | 120 V: 5–125 A | 230 V: 5–205 A |
| Output Range — Stick | 120 V: 5–90 A | 230 V: 5–170 A |
| Rated Output (230 V) | TIG: 205 A / 18.2 V @ 25% | 130 A / 100% | Stick: 170 A @ 25% | 100 A @ 100% |
| Rated Output (120 V) | TIG: 90 A / 13.6 V @ 30% | Stick: 80 A / 23.2 V @ 30% |
| Polarity | AC/DC |
| Pulse Frequency | 0.1–500 Hz (230 V) / 0.1–20 Hz (120 V) |
| AC Frequency | 60–150 Hz |
| AC Balance | 60–90% |
| Display | 4.3" Full-Color LCD (EN/ES/FR) |
| Arc Start | High-Frequency Start & Lift TIG Start |
| Foot Pedal Compatible | Yes — Foot Amptrol included (25 ft, 6-pin Lincoln) |
| Remote Control | 6-Pin Lincoln connector standard |
| Work Lead Connector | Dinse |
| Net Weight | 36 lbs (16.3 kg) |
| Dimensions (H×W×D) | 14.75" × 9.27" × 21" (375 × 235 × 534 mm) |
| Warranty | 3 Years (Lincoln Electric factory) |
| Condition | New — Lincoln Electric K-prefix (factory-new) |
- Square Wave 205 Power Source (K5613-1)
- Premium Caliber TIG Torch with Flexible Head — 12.5 ft, 200 A rated
- Foot Amptrol — 25 ft, 6-pin Lincoln connector (K870)
- Gas Regulator / Flowmeter with hose
- Work Cable & Clamp — 10 ft
- Electrode Holder with cable — 200 A, 35% duty cycle
- TIG Torch Consumable Kit: gas lenses, ceramic cups, tungsten electrodes (0.040" to 3/32" ceriated), collets, and collet bodies
- 120 V / 230 V input power adapter
- Operator's manual (printed + USB)
Expand the Square Wave 205's capability with WeldingMart's Lincoln-compatible accessories:
- TIG Torches — Air-cooled PTA-17 and PTA-26 torches in 12.5 ft and 25 ft lengths; flexible-neck bodies for pipe, tube, and corner welds; replaceable torch heads for worn or contaminated tips without replacing the full cable assembly.
- TIG Filler Rod — ER4043 and ER5356 for aluminum; ER308L, ER309L, ER316L for stainless steel; ER70S-2 and ER70S-6 for mild steel; ER80S-B2 and ER90S-B3 for chrome-moly; ERTi-2 and ERTi-5 for titanium. Available in 1 lb and 10 lb packs.
- Foot Pedals & Amptrol — Additional Lincoln 6-pin compatible foot pedals for remote amperage control during TIG; thumb controls for out-of-position work where a foot pedal is impractical.
- Argon Regulators — Single-stage and dual-stage CGA-580 flowmeters for pure argon (TIG standard) and argon/helium blends for thicker aluminum; compact inline regulators for portable 120 V operation.
- TIG Consumable Kits — Premium gas lens kits (1/16", 3/32", 1/8" ceriated and lanthanated tungsten); ceramic cup assortments; collet and collet body packs; back cap sets. Gas lens conversion dramatically improves shielding coverage on aluminum and stainless TIG — recommended for any welder using the SW205 for precision work.
The Square Wave 205's 5–205 A range, dual-voltage input, and advanced AC controls make it one of the most versatile portable TIG machines in its class:
- Automotive fabrication & restoration. DC TIG at 120 V welds thin 22-gauge stainless exhaust flanges, mild steel body panels, and 4130 chromoly tubing for race car chassis and roll cages. Switch to 230 V for heavier brackets and frame sections up to 1/4". High-frequency pulse tightens the arc cone on tube joints where heat control is critical. Store setups for each material to minimize setup time between jobs.
- Aluminum welding — marine, automotive, aerospace. AC TIG with variable balance (60–90%) and adjustable frequency (60–150 Hz) handles everything from thin 18-gauge aluminum sheet on motorcycle tank patches to 3/8" marine aluminum plate on boat transom repairs. Frequency at 120 Hz narrows the arc width for controlled bead placement; balance set to 65% reduces tungsten wear and ball formation on long aluminum runs.
- Sheet metal fabrication & artistic metalwork. 0.1 Hz pulse at low current (20–40 A) lets beginners bridge gaps and weld short-circuit without burn-through on 20-gauge and 22-gauge stainless or mild steel. Artists and sculptors use the SW205 for delicate copper and bronze TIG, controlling heat precisely with the foot Amptrol across thin-wall tube and rod assemblies.
- Stainless steel food equipment, brewery, and pharmaceutical. DC TIG on 304L and 316L stainless with ER308L and ER316L filler produces low-carbon, corrosion-resistant welds required for sanitary tubing, vessels, and fittings. The SW205's 130 A @ 100% duty cycle supports sustained production TIG runs without shutdown cycles in shop environments.
- Education, training, and makerspaces. The built-in parameter guide, multilingual LCD, and comprehensive included kit make the SW205 a natural choice for welding programs at community colleges, vocational schools, and makerspaces. Students learn AC frequency and balance on aluminum without purchasing separate controllers — all controls are on the front panel, explained by the on-screen guide.
The Square Wave 205 (K5613-1) replaces the Square Wave TIG 200. Key upgrades: 5 A higher max output (205 vs. 200 A on 230 V), a 4.3" full-color LCD display replacing the older segment display, pulse frequency extended to 500 Hz (vs. approximately 20 Hz on the TIG 200), and a built-in parameter guide for material/thickness-based setup. The TIG 205 also adds dedicated E6010 crisp and E7018 soft Stick modes. The included accessories package is more complete, with a premium flexible-head torch and a 25-ft foot Amptrol.
Yes, with some limitations. On 120 V, the SW205 delivers up to 125 A AC TIG output — sufficient for aluminum up to approximately 1/8" thick (3 mm) using the rule of thumb of 1 A per 0.001" of aluminum thickness. For heavier aluminum (3/16" to 3/8"), use 230 V input for the full 205 A output. The machine auto-detects the input voltage — no manual reconfiguration required.
Yes. The K5613-1 ships with a 25-ft Foot Amptrol (6-pin Lincoln connector) for remote amperage control during TIG welding. The foot pedal lets you ramp current up and down while keeping both hands on the torch and filler rod — critical for aluminum TIG where heat management varies as the base material heats up during the weld.
Lincoln recommends 2% ceriated tungsten for the Square Wave 205 on aluminum, pointed to a fine point or blunt taper. The machine's AC frequency and balance controls allow the tungsten to form a small hemispherical ball at the tip during operation — normal and desirable on AC TIG. Do not sharpen aluminum TIG tungsten to the same sharp point used for DC TIG on steel. The included TIG kit contains 2% ceriated tungsten in 0.040", 1/16", and 3/32" diameters.
Yes, the SW205 is inverter-based and handles minor generator voltage fluctuation well. Lincoln recommends a generator with at least 6,000 watts (6 kVA) for 120 V TIG operation and 10,000 watts (10 kVA) for 230 V full-output TIG. Use a generator with electronic governor (inverter-type generator) for the cleanest waveform when HF arc start is active — standard generators with mechanical governors may cause occasional HF interference but generally work adequately for DC TIG and Stick.