The Lincoln Electric Precision TIG® 225 is a 225-amp inverter TIG and Stick welder built for fabrication shops, vocational programs, and professionals who need reliable AC/DC output from a compact 230 V machine. Unlike entry-level TIG machines, the Precision TIG 225 delivers independent AC frequency control (20–150 Hz), adjustable AC balance, and built-in high-frequency arc start — features that separate it from budget inverters and make it capable of production-quality aluminum and stainless work day after day. With a foot-pedal amperage control included, welders get fingertip command of the puddle without reaching for the panel.
| Specification | Value |
|---|---|
| Model / Part Number | Precision TIG 225 (K2535-1) |
| Welding Process | AC TIG (GTAW), DC TIG (GTAW), Stick (SMAW) |
| Output Range — DC TIG | 5–225 A |
| Output Range — AC TIG | 5–200 A |
| Duty Cycle | 40% @ 200 A AC; 40% @ 225 A DC |
| Input Voltage | 208–230 V, 1-Phase, 60 Hz |
| Max Input Current | 26 A (230 V) |
| Arc Start | High-Frequency (HF); Lift-Arc (DC) |
| Pulse | 0.1–10 Hz (DC only) |
| AC Frequency Control | 20–150 Hz |
| AC Balance Control | 15–85% electrode negative (EN) |
| Foot Pedal | Included (K870) |
| Post-Flow Gas Control | Yes — adjustable |
| Weight | 26 lb (11.8 kg) |
| Dimensions (H × W × D) | 10.9 × 7.7 × 19.5 in |
| Certifications | CSA, CE |
Source: Lincoln Electric Precision TIG 225 product page. Specifications subject to change; verify with current Lincoln documentation before qualifying a welding procedure.
The Precision TIG 225 covers the full range of light-to-medium fabrication TIG work:
- Vocational & Training Environments: The included foot pedal and intuitive front panel make the Precision TIG 225 the go-to training machine in welding schools and apprenticeship programs across North America. Students learn amperage control on a machine identical to what they'll operate on the shop floor.
- Motorsport Fabrication: 4130 chromoly roll cage tubes, aluminum suspension components, and stainless exhaust systems — diameters and wall thicknesses common in chassis shops fall well within the 225 A output range.
- HVAC & Plumbing: Copper and stainless tubing joints requiring clean, leak-free welds. DC TIG on copper with ERCuSi-A filler delivers joint integrity that soldering can't match in high-pressure applications.
- Maintenance & Repair: The Stick (SMAW) function handles everything from carbon steel structural tack-ups to hard-facing overlays when the TIG torch isn't the right tool.
- Aluminum Boat & Marine: AC TIG on 5052, 5083, or 6061 aluminum sheet and extrusions for hulls, fuel tanks, and brackets.
AC frequency and bead width: Higher AC frequency (100–150 Hz) narrows the arc cone, producing a narrower, more penetrating bead ideal for tight joints and thin material. Lower frequency (20–40 Hz) widens the arc for fast fill on thicker aluminum sections. The Precision TIG 225's 20–150 Hz range gives you practical control of this variable without needing a premium-tier machine.
AC balance and oxide cleaning: The balance control determines what fraction of the AC cycle runs electrode-negative (EN). More EN (70–85%) means more penetration, less electrode heat, and finer cleaning — use this for thicker aluminum. Less EN (15–40%) increases oxide cleaning action; useful for badly oxidized or cast aluminum, but generates more electrode heat and a wider bead.
Foot pedal amperage control: The included K870 foot pedal lets you ramp amperage from near-zero up to the panel-set maximum. This is essential for starting and finishing TIG beads cleanly on aluminum (where crater cracks form without proper current taper) and for bridging gaps or handling changing material thickness mid-pass.
Comparison to the Aspect 230: The Precision TIG 225 offers a higher pulse frequency on its DC circuit and ships with the foot pedal included. The Lincoln Aspect 230 adds 500 Hz pulse capability and a lighter, more compact inverter platform at similar output. Both machines share 208–230 V, single-phase input. For dedicated aluminum production work above 1/4 in thick, also consider the 300–375 A TIG options in our welder collection.
Does the Lincoln Precision TIG 225 come with a TIG torch?
Yes. The Precision TIG 225 ships standard with a gas-cooled TIG torch, foot amperage control pedal (K870), work clamp, and input power cord. You will need to supply your own shielding gas regulator, argon cylinder, and filler rod. For aluminum, use ER4043 or ER5356 filler. For stainless, use ER308L or ER316L.
Can the Precision TIG 225 weld 1/4-inch aluminum?
Yes, with preheat. At 200 A AC, the Precision TIG 225 can produce a quality weld on 1/4 in (6.4 mm) aluminum. For single-pass full-penetration welds on 1/4 in, expect to run near maximum output. Groove the joint (V-groove or J-groove) for reliable fusion. For 3/8 in and thicker sections, consider the Lincoln Precision TIG 375 or Aspect 375, which offer more sustained amperage capacity.
What shielding gas do I use with the Precision TIG 225?
Use 100% argon for all TIG welding on aluminum, stainless, titanium, and most other metals. Argon-helium blends (25–50% He) increase arc energy and travel speed on thicker aluminum. Never use CO₂ or mixed shielding gas (MIG gases) with TIG — they will cause arc instability and weld contamination. Set your regulator to 15–20 CFH for most applications; increase to 20–25 CFH on larger-diameter cup setups or in drafty environments.
Is the Precision TIG 225 suitable for chromoly 4130 pipe welding?
Yes. Use DC TIG with ER80S-B2 filler rod for chrome-moly steel, or ER70S-2 for mild steel and 4130 at lower strength requirements. The HF arc start and clean DC output of the Precision TIG 225 make it well-suited for root and fill passes on schedule pipe. Preheat requirements for P11 and P22 pipe per AWS D10.8 still apply regardless of machine choice. See our Lincoln ER80S-B2 TIG rod for P11 pipe applications.
What is the difference between HF start and Lift-Arc on the Precision TIG 225?
High-frequency (HF) start fires a high-voltage, high-frequency spark across the gap between the tungsten and workpiece to initiate the arc without contact — keeping the tungsten pristine. This is the preferred mode for AC aluminum work. Lift-Arc initiates the arc by briefly touching the tungsten to the work then lifting; it's lower-EMI and preferred near sensitive electronics or CNC equipment. The Precision TIG 225 offers both, selectable from the front panel.