The short answer: MIG vs TIG welding — the key differences, advantages, and when to use each process. Written by Varlowe's coded welding team with 20+ years of hands-on fabrication experience.
MIG and TIG welding are two of the most common welding types used in industrial fabrication. Both use an electric arc and shielding gas, but they work differently and are suited to different applications. Choosing the wrong process for the job costs time, money, and quality — here's everything you need to know to make the right call.
MIG (Metal Inert Gas) welding uses a continuously fed wire electrode that acts as both the electrode and the filler metal. It is semi-automatic, fast, and well-suited to production welding on mild steel, stainless steel, and aluminium. The formal technical name is GMAW — Gas Metal Arc Welding. Under BS EN ISO 4063, MIG with solid wire is process 131; MAG with solid wire is process 135.
TIG (Tungsten Inert Gas) welding uses a non-consumable tungsten electrode to generate the arc. Filler metal is added separately by hand. It produces exceptionally clean, precise welds with no spatter. TIG is preferred for stainless steel, aluminium, titanium, and any application where weld quality or appearance is non-negotiable. The formal name is GTAW — Gas Tungsten Arc Welding. Under BS EN ISO 4063, TIG is process 141.
The table below covers the key technical and practical differences across every factor that matters in industrial fabrication and welding specification decisions.
| Factor | MIG (GMAW) | TIG (GTAW) |
|---|---|---|
| Process standard (BS EN ISO 4063) | 131 (MIG solid wire) / 135 (MAG solid wire) | 141 (TIG) |
| Electrode | Consumable wire, continuously fed from spool | Non-consumable tungsten — does not melt |
| Filler metal | The wire electrode is the filler — automatic | Separate filler rod, fed by hand |
| Shielding gas | Argon/CO₂ mix (C25) for steel; pure argon for aluminium | Pure argon for most metals; helium mixes for thick aluminium and copper |
| Speed / deposition rate | Fast — wire feeds continuously; high deposition rates | Slow — manual filler addition; lower deposition rates |
| Heat input & distortion | Higher heat input; greater distortion risk on thin material | Precise heat control via foot pedal; minimal distortion on thin sections |
| Weld appearance | Good; some spatter typical; dressing often required | Excellent; clean, spatter-free; minimal post-weld finishing |
| Skill level required | Moderate — semi-automatic operation; shorter learning curve | High — two-handed coordination; years to master |
| Material suitability | Mild steel, carbon steel, stainless steel, aluminium | Stainless, aluminium, titanium, nickel alloys, copper, exotic metals, dissimilar metals |
| Material thickness | Best on 3mm and above; manageable on thinner material with short-circuit transfer | Excellent on thin gauge (0.5mm+); full range with correct technique |
| Welding positions | All positions with short-circuit transfer; flat/horizontal preferred for spray transfer | All positions |
| Cost | Lower — faster process, lower labour cost per metre of weld | Higher — slower process, higher skill premium, greater labour cost |
| Coded standard (UK) | BS EN ISO 9606-1 (steels); BS EN ISO 9606-2 (aluminium) | BS EN ISO 9606-1 (steels); BS EN ISO 9606-2 (aluminium) |
| Typical applications | Structural steelwork, general fabrication, automotive, shipbuilding, construction | Pressure pipework, food-grade/pharma stainless, aerospace, root passes, architectural metalwork |
Yes — and it's common practice. The most typical example is pipe welding: TIG for the root pass (where penetration quality and integrity are critical) and MIG for the fill and cap passes (where speed matters more). Many fabrication projects combine TIG for stainless or precision elements with MIG for the structural carbon steel sections. Specifying the right process per joint rather than defaulting to one for the whole project is what good welding engineers do.
Varlowe Industrial Services provides both MIG and TIG welding, including coded welding to BS EN ISO 9606. Our team holds the relevant coded qualifications for both processes and can advise on the right process for your project from the outset. Visit our Welding Services page or contact us to discuss your requirements.
MIG welding uses a continuously fed consumable wire electrode that acts as both electrode and filler, making it faster and semi-automatic. TIG welding uses a non-consumable tungsten electrode with filler rod fed separately by hand, producing cleaner and more precise welds at lower speed. MIG is preferred for structural mild steel and production work; TIG for stainless steel, aluminium, and precision or safety-critical applications.
Both processes produce welds as strong as the base material when performed correctly by a qualified welder. TIG produces cleaner, more consistent welds with fewer defects, which matters in high-specification applications. Weld strength depends more on operator skill, joint preparation, and correct process selection than on the process name alone.
MIG is the better choice when welding structural mild steel, when deposition rate and speed matter, for thick sections in flat or horizontal positions, and for production runs where semi-automatic operation increases throughput. MIG is also more cost-effective for large-volume fabrication where TIG's precision is not required.
TIG is the better choice for stainless steel, aluminium, titanium, and thin-gauge materials. Use TIG for root passes on pipe and tube welds, for safety-critical or pressure-bearing applications, and whenever the specification requires maximum weld integrity.
Yes — this is common practice in industrial fabrication. A typical approach for pipe welding is TIG for the root pass and MIG for fill and cap passes. Many projects combine TIG for stainless or precision elements with MIG for structural carbon steel sections.