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- Best-in-class entry TIG at demo pricing. The Square Wave TIG 200 is Lincoln's most popular hobby-to-professional crossover TIG machine. Factory demo units offer 15–25% off street pricing while carrying the same 3-year manufacturer warranty as a new unit — exceptional margin for buyers stepping up from 110 V flux-core machines.
- Dual-voltage, go-anywhere portability. At 46.5 lbs, this machine plugs into a 120 V household outlet or 230 V shop drop without adapter boxes or rewiring. Lincoln's "Take it Everywhere, Plug in Anywhere" philosophy means it's as useful in a home garage as a production bay.
- Ships ready — no back-order wait. Lincoln new-production TIG machines can carry 6–10 week lead times during peak demand. This factory demo ships from WeldingMart's warehouse in 1–3 business days.
| SKU / Model | U5126-1 (Factory Demo) |
| Output Range (TIG) | 120 V input: 10–125 A; 230 V input: 10–200 A |
| Output Range (Stick) | 120 V: 10–90 A; 230 V: 10–170 A |
| Polarity | AC/DC |
| Input Voltage | 120 / 230 V, 1-Phase, 50/60 Hz (dual voltage) |
| Input Current (TIG, 120 V) | 25% DC: 21 A; 40% DC: 17 A; 60% DC: 14 A |
| Input Current (TIG, 230 V) | 25% DC: 22 A; 40% DC: 17 A; 60% DC: 13 A |
| AC Frequency Control | Adjustable — narrow or wide bead profile on aluminum |
| AC Balance Control | Adjustable — cleaning vs. penetration ratio |
| Pulse Mode | Yes — standard feature |
| Net Weight | 46.5 lbs / 21.1 kg |
| Dimensions (H×W×D) | 14 in × 10.75 in × 19.25 in (358 × 282 × 502 mm) |
| Work Lead Connector | Dinse |
| Warranty | 3 Years — full factory warranty |
| Condition | Factory Demo / Reconditioned — Lincoln Electric certified |
- Square Wave TIG 200 Power Source
- TIG Torch with cable assembly
- Gas Regulator / Flowmeter
- Work Cable & Clamp
- Input Power Cord (120 V and 230 V adapters)
- Electrode Holder & Cable
- Starter tungsten electrode kit
The Square Wave TIG 200 uses standard #17/26-series torch consumables and Dinse connectors. Popular accessories at WeldingMart:
- Flex-Neck TIG Torches — 12.5 ft and 25 ft air-cooled PTA-17 and PTA-26 torches for tight-corner access
- TIG Filler Rod — ER4043 and ER5356 aluminum filler; ER308L stainless; ER70S-2 carbon steel in 1 lb and 10 lb packs
- Argon Flowmeter Regulators — single-stage CGA-580 regulators compatible with standard argon cylinders
- TIG Consumables Kit — 3/32 in and 1/16 in ceriated tungsten, collets, and Furick ceramic cups for argon-lens setups
The Square Wave TIG 200's dual-voltage AC/DC capability makes it a go-to machine for hobbyists, motorsports fabricators, and small-shop professionals:
- Motorsports & automotive fabrication. Weld 4130 chromoly tube chassis, aluminum suspension components, and stainless exhaust systems from the same machine. Pulse mode reduces distortion on thin-wall tubing where heat control is critical.
- Fine sheet metal work. DC TIG at 10–200 A with pulse handles 18–22 gauge 304 stainless for custom HVAC, food equipment, and art fabrication without warping or burn-through.
- Aluminum welding — bikes, boats, and brackets. Adjustable AC frequency (narrow vs. wide bead) and AC balance control let even intermediate welders dial in clean, consistent aluminum beads on cast, extruded, and plate stock from 1/16 in to 3/8 in.
- Home shop & garage use. The 120 V input lets you TIG weld on a standard 20 A household circuit — useful for apartments, garages with limited panel capacity, or outdoor use with a generator.
- Aerospace maintenance & repair. DC TIG on titanium, Inconel, and stainless aerospace hardware benefits from the machine's HF arc start (no contact arc initiation) and precise low-end amperage control starting from 10 A.
This unit was manufactured to Lincoln Electric's full production standards, used for authorized demonstrations or distributor evaluation, then returned to Lincoln's refurbishment center. It has been inspected, repaired to factory spec, tested to perform identically to a new machine, and assigned a U-prefix SKU (U5126-1). It carries a full 3-year Lincoln Electric factory warranty.
Yes. On 120 V, the machine delivers up to 125 A TIG output — sufficient for aluminum up to 1/8 in and steel up to 3/16 in. For heavier aluminum work, connect to 230 V for the full 200 A output. The machine switches automatically; no internal rewiring required.
Yes — the Square Wave TIG 200 is an AC/DC machine. AC output is required for aluminum TIG welding (GTAW-AC breaks the aluminum oxide layer). Adjustable AC frequency (20–200 Hz) controls bead width, and AC balance adjusts the cleaning-to-penetration ratio. It welds aluminum from 1/16 in sheet to 3/8 in plate on 230 V.
Electrically and mechanically identical — same output range, same features, same AC controls, same duty cycle. Factory demo cosmetics may include light marks from handling. The price difference (typically 15–25% below MAP) and the identical warranty are the main distinctions buyers care about.
WeldingMart ships this machine to the U.S. lower 48 states via ground freight. Alaska, Hawaii, and international shipping may be available at additional cost — contact our sales team for a freight quote before ordering.
Looking for the brand-new version? See brand-new Square Wave TIG 200 or browse all Lincoln TIG Welders and our full used TIG welders collection.
The Lincoln Square Wave TIG 200 Factory Demo represents an exceptional opportunity to acquire professional-grade TIG welding capability at enhanced value without compromising on performance or features. This versatile and portable welding system combines advanced TIG functionality with stick welding capability in a compact package designed specifically for hobbyists, makers, small fabricators, and craftsmen seeking to expand their creative possibilities. With its intuitive user interface and progressive feature set, the Square Wave TIG 200 effectively grows with the user, providing immediate accessibility for beginners while offering advanced capabilities that more experienced welders will appreciate.
At the core of the Square Wave TIG 200 is Lincoln's sophisticated AC/DC TIG technology, delivering remarkably smooth and stable welding performance across diverse materials. The system provides exceptional AC TIG welding on aluminum with adjustable AC frequency control that allows users to easily modify the welding bead profile for specific applications. The adjustable AC balance feature enables optimization for either enhanced cleaning action on contaminated aluminum or maximum penetration on thicker materials. For steel, stainless steel, and chrome-moly applications, the Square Wave TIG 200 delivers precise DC TIG welding with outstanding arc stability and control.
Despite its comprehensive capabilities, the Square Wave TIG 200 maintains exceptional portability at just 46.5 pounds, making it ideal for applications requiring mobility. Its dual voltage input flexibility allows connection to either standard 120V circuits for convenience or 230V power for maximum output performance - truly embodying Lincoln's "Take it Everywhere, Plug in Anywhere" philosophy. Advanced features such as pulse mode, which provides a rhythmic cadence for filler metal deposition, help users develop better technique and achieve professional results more quickly. This factory demo unit has been thoroughly inspected and certified by Lincoln Electric to ensure proper operation while offering exceptional value for welders seeking premium TIG capability for automotive, brewery, distillery, general fabrication, or maintenance applications.
- Advanced AC/DC TIG welding capability with smooth, stable performance on aluminum, steel, stainless steel and chrome-moly
- User-friendly interface with "set it and forget it" simplicity for operators of all experience levels
- Adjustable AC Frequency Control for customizing bead width and appearance on aluminum applications
- Adjustable AC Balance for optimizing between cleaning action and penetration on aluminum
- Pulse mode functionality providing rhythmic cadence for improved filler metal deposition and technique development
- Multi-process capability with both precision TIG welding and versatile stick welding from a single power source
- Dual voltage input flexibility (120V/230V) allowing connection to standard household circuits or higher power for maximum output
- Exceptional portability at just 46.5 pounds for convenient transportation between job sites
- Factory demo unit offering premium technology at enhanced value with full manufacturer certification
| Dimensions (H x W x D) | 14 in x 10.75 in x 19.25 in (358 mm x 282 mm x 502 mm) |
| Net Weight | 46.5 lbs (21.092 kg) |
| Work Lead Connector Type | Dinse |
| Input Voltage | 120/230 |
| Input Current | 120V TIG: 25% Duty Cycle 21A 40% Duty Cycle 17A, 60% Duty Cycle 14A, Stick: 20% Duty Cycle 19A 60% Duty Cycle 16A 230V TIG: 25% Duty Cycle 22A 40% Duty Cycle 17A 60% Duty Cycle 13A |
| Input Hertz | 50/60 |
| Input Phase | 1 |
| Input Power | 120/230/1/50/60 |
| Mode Icon | CC |
| Output Range | 120V TIG: 10-125A, Stick: 10-90A, 230V TIG: 10-200A, Stick: 10-170A |
| Polarity | AC/DC |
| Typical Application | Automotive Brewery Distillery General Fabrication Maintenance & Repair |
| Warranty | 3 Years |