The Lincoln Factory Demo AC-225 Stick Welder (U1170) is a time-tested transformer-based arc welder delivering 225 amps of smooth AC output — a go-to machine for farm shops, maintenance crews, and repair professionals who demand dependable stick welding performance without complexity. This factory demo unit has been inspected and certified by Lincoln Electric and ships with a full 3-year factory warranty at a substantial price reduction versus new.
- Factory warranty at demo pricing. The U1170 carries Lincoln Electric's full 3-year warranty — the same coverage as a brand-new K1170 — at a price reflecting its factory demo status. You get proven transformer reliability without paying full retail.
- Simple, bulletproof operation. No inverter boards, no digital displays. The AC-225's full-range selector dial (40–225A) is all the control most maintenance and repair applications require. Fewer components means fewer failure points over a long service life.
- Broad electrode compatibility. The 225A AC output handles E6011, E6013, E7018-AC, stainless, and hardfacing rods up to 3/16 in. mild steel or 5/32 in. low-hydrogen, giving farm and shop welders maximum electrode flexibility without switching machines.
| Output Process | Stick (SMAW) |
| Output Polarity | AC |
| Amperage Range | 40 – 225 A |
| Rated Output (Duty Cycle) | 225 A / 25 V / 20% |
| Open Circuit Voltage (OCV) | ~80 V (AC transformer) |
| Electrode Size Range | 3/32 in. – 3/16 in. (mild steel); up to 5/32 in. low-hydrogen |
| Input Voltage / Phase / Hz | 230 V / 1-Phase / 60 Hz |
| Input Current | 50 A |
| Input Plug | NEMA 6-50P (factory-installed) |
| Input Power Cable | 6 ft. (1.8 m) factory-attached |
| Dimensions (H × W × D) | 24 in × 17.25 in × 12 in (610 × 438 × 305 mm) |
| Net Weight | 96 lbs (43.5 kg) |
| Certifications | NEMA rated, UL listed, CUL/CSA approved |
| Warranty | 3 Years (Lincoln Electric factory warranty) |
- Lincoln AC-225 Stick Welder (factory demo unit, U1170)
- 6 ft. factory-attached input power cable with NEMA 6-50P plug
- Lincoln Electric operator's manual
- Factory inspection and certification documentation
Note: Electrode holder, work clamp, and welding leads are not included. See welding leads and electrode holders below.
Complete your AC-225 setup with these essential stick welding accessories available at WeldingMart:
- Stick Welding Electrodes & Rods — E6011, E6013, E7018-AC, hardfacing, stainless rods in all diameters compatible with the AC-225's 40–225A range.
- Welding Leads — Electrode holders and work clamp leads in 25 ft., 50 ft., and 100 ft. lengths. The AC-225 requires leads rated for 225A AC output.
- Electrode Holders — 300A and 500A jaw-style holders compatible with the AC-225. A properly rated holder prevents heat buildup and ensures secure rod grip throughout the weld pass.
- Chipping hammer & wire brush — Slag removal is part of every stick weld. Keep a quality chipping hammer on hand for clean bead presentation between passes.
- Welding gloves & helmet — AC arc produces strong UV/IR radiation. Use a welding helmet with a minimum #10 shade lens and leather stick-welding gloves rated for the amperage range.
The AC-225's 225A output and broad electrode compatibility make it a versatile choice across a wide range of real-world applications:
- Farm and Ranch Repair. Broken implement frames, cracked trailer hitches, livestock equipment — the AC-225 handles the carbon steel repair work that keeps a farm running. Its E6011 capability welds through surface rust and mill scale without extensive prep.
- Structural Fabrication (Light Duty). Gate frames, fence posts, equipment platforms, and structural repairs up to 3/4 in. plate (multi-pass) are within the AC-225's capability with correct electrode selection and amperage setting.
- Maintenance and Repair Welding. Plant maintenance crews rely on the AC-225 for welding carbon steel pipe, machinery frames, conveyor components, and wear-plate repair. The full-range selector allows dialing in precisely to the base metal thickness.
- Pipeline and Utility Work (Light). For smaller-diameter carbon steel pipe work and utility connections, the AC-225 with E6011 provides the penetrating arc needed on pipe grades. Not rated for critical pressure pipe without procedure qualification.
- Vocational Training. The AC-225 is one of the most widely used training machines in American welding programs. Its straightforward controls and forgiving arc teach fundamental SMAW technique without digital variables to confuse new learners.
- Cast Iron Repair. With nickel-iron electrodes (ENiFe-CI), the AC-225 can handle cast iron repair on engine blocks, manifolds, and machine castings — a common farm and industrial maintenance task.
Yes. The U1170 factory demo unit carries Lincoln Electric's full 3-year machine warranty — identical to a new K1170 purchase. Lincoln Electric certifies all factory demo units before sale, and the warranty starts from your purchase date.
The AC-225's AC output is compatible with: E6011 (all-position, penetrating, works through rust/mill scale), E6013 (smooth arc, light sheet metal), E7018-AC (low-hydrogen AC version — check electrode spec for AC compatibility), E7024 (flat/horizontal drag rod, high deposition), stainless AC rods, and hardfacing electrodes rated for AC. The AC-225 does not support DC-only electrodes like standard E6010 — use E6011 as the cellulosic equivalent on AC machines.
Yes, with AWS E308-16 or E309-16 AC-compatible stainless electrodes. For thin stainless (under 1/8 in.), the 40A minimum output gives reasonable amperage control, though inverter machines are generally preferred for thin stainless. For weld-repair on 304 or 316 stainless structural applications, the AC-225 is fully capable.
The K1170 is a new-production Lincoln AC-225. The U1170 is a factory demo unit — a machine that was used for demonstration or testing purposes, then returned to Lincoln Electric, inspected, recertified, and resold with a full warranty. Mechanically and electrically, the U1170 performs identically to the K1170. The difference is price (lower for U1170) and cosmetic condition (may have minor surface marks from demo use).
The AC-225 requires a 230V, 50A, single-phase circuit with a NEMA 6-50 receptacle. It comes with a factory-installed NEMA 6-50P plug and 6 ft. power cord. If your shop or garage has a standard 240V dryer outlet (NEMA 14-30), you'll need a proper adapter or a dedicated NEMA 6-50 circuit installed by a licensed electrician.
Identically in performance. The transformer inside the AC-225 is one of the most reliable welding components ever manufactured — transformer-based machines can run for decades with minimal service. Factory demo units are low-hour machines that have been verified against Lincoln's quality standards. The cost savings are real; the performance difference is not.
Looking for the brand-new version? See the Lincoln Stick Welders collection or browse all stick welders at WeldingMart. You can also compare the demo stick welders collection for the full range of factory demo options.