- Description
The TecArc Si 403 Pro MIG Welder with separate wire feeder is a powerful and versatile welding machine, built in the UK for professional fabricators and workshops. Designed for reliability and performance, the Si Pro range offers smooth, stable MIG welding on mild steel, stainless steel, and aluminium. With a separate wire feed unit, it provides greater flexibility, improved wire delivery, and easy handling perfect for medium to heavy-duty welding applications.
We know many customers like the simplicity, reliability and cost of traditional transformer MIG welders and we don't disagree. However, UK & EU regulations mean we have had to re-design our complete range. We now have the best heavy duty inverter power outputs to compete with the best German and American machines.
Engineered for durability, these industrial MIG welders feature robust construction, user-friendly controls, and precise arc characteristics, making them ideal for both production environments and custom fabrication. The TecArc Si Pro MIG welder is a cost-effective solution for welders who demand consistent results, long service life, and excellent value.
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Key Features of the TecArc Si 403 Pro MIG Welder
Wide Amperage Range (20- 400 A)
Enables welding from thin sheet metal up to heavier fabrication work.
High Duty Cycle
At 60% duty cycle, it delivers ~370 amps, which means it can weld for long periods without overheating. Great for production environments.
Separate Wire Feeder
Gives flexibility: you can place the feeder nearer to the welding site, reducing wire run, improving feed reliability, and keeping the power source out of dust/grinding zones.
4-Roll All-Geared Wire Drive
Ensures smoother, stable wire feeding, especially for softer wires like aluminium. Offers better grip and fewer feeding issues.
Infinitely Variable Voltage & Wire Speed Controls
Allows fine control of welding parameters, tailoring the arc to material, thickness, type of wire. More precision = less spatter + better weld quality.
Digital Meters & Display
Shows set and actual values during welding; helps with repeatability, precise setup, and easier monitoring.
Multi-Process Welding Capability
Supports MIG/MAG, MMA (stick), and DC Lift TIG, plus spool gun option for aluminium. Very versatile.
Reversible Polarity & Trigger Modes
Includes reverse polarity for gasless wire types, selectable trigger modes (2T/4T), and adjustable burn-back. Good control and flexibility in different welding scenarios.
Generator & Long Extension Cable Friendly
Auto compensation for voltage drop, built to handle less-than-perfect power supply conditions. Useful for on-site or remote work.
Robust Build / UK Made
British built, rugged construction, galvanised chassis, quality components, good support/spares. Gives confidence in durability and long-term investment value.
Suitable for Multiple Materials
Capable of welding mild steel, stainless steel, aluminium, duplex, Hardox etc. Useful if you work with different metals.
Low Spatter, Smooth Arc Start
Makes for cleaner work, less post-weld cleaning, better finish.
Safety & Efficiency Features
Includes over-/under-voltage protection, cooling, robust wiring, built-in gas controls, etc
Supplied with S44 wire feeder, spool cover, MB36-3M MIG torch, regulator, 3M intercon lead, 3M earth lead and gas hose.
Model Output amps range Duty cycle @ 40 degrees Power supply and fuse rating OCV Si301 20A - 300A 300A @ 60% 230V 32A D 70V Si401 20A - 400A 380A @ 60% 230V 32A/45A D 70V Si501 30A - 500A 480A @ 60% 230V 45/63A D 75V Si303 20A - 300A 300A @ 60% 400V 16A 70V Si403 20A - 400A 380A @ 60% 400V 16/20A 70V Si503 30A - 500A 480A @ 60% 400V 20/32A 70V Dimensions
Power source case size: 330W x 550H x 620L
Wire feeder case size: 200W x 260H x 410L + extra for castors and wire spool cover