Welding is one of those trades that looks straightforward until you realise there are several very different processes, each with its own strengths, limitations and learning curve. Whether you're eyeing off a small gate repair, a trailer build or a stainless steel handrail, knowing the difference between MIG, TIG and stick welding will help you choose the right approach — or the right tradesperson.
MIG Welding (GMAW)
MIG welding — short for Metal Inert Gas, technically known as Gas Metal Arc Welding (GMAW) — is the most common process you'll encounter in home workshops and light fabrication across New Zealand. A continuously fed wire electrode melts into the weld pool while a shielding gas (typically argon or a mixed gas) protects the weld from atmospheric contamination.
Why people choose MIG
- Easier to learn than TIG or stick — most beginners can lay a reasonable bead within a few hours of practice
- Fast travel speeds make it efficient for longer runs and thicker material
- Works well on mild steel, stainless steel and aluminium (with the right wire and gas)
- Good for sheet metal, structural steel, trailers, gates and general fabrication
Limitations of MIG
- Needs a shielding gas cylinder, which adds cost and means it's less portable outdoors in windy conditions
- Not ideal for very thin or exotic metals where precision is critical
- Weld quality depends heavily on correct gas flow, wire speed and voltage settings
TIG Welding (GTAW)
TIG welding — Tungsten Inert Gas, or Gas Tungsten Arc Welding (GTAW) — uses a non-consumable tungsten electrode to create the arc, while filler rod is fed in separately by hand. Argon shielding gas is almost always used.
Why people choose TIG
- Produces the highest quality, cleanest welds of the three processes — excellent for visible or structural joins
- Precise heat control makes it ideal for thin materials, stainless steel, aluminium and exotic alloys like titanium
- Popular for food-grade fabrication, motorbike frames, artistic metalwork and marine fittings
- Very low spatter, minimal post-weld cleanup
Limitations of TIG
- Steepest learning curve — requires both hands and often foot pedal control simultaneously
- Slower than MIG, so less economical for large or repetitive jobs
- Equipment is generally more expensive
- Not well suited to dirty, rusty or painted metal
Stick Welding (SMAW)
Stick welding — Shielded Metal Arc Welding (SMAW) — is the oldest and most rugged of the three. A flux-coated consumable electrode (the "stick") creates the arc and provides its own shielding as the flux burns off, producing a slag layer over the weld.
Why people choose stick
- Highly portable — no gas cylinder required, works off a basic transformer or inverter welder
- Tolerates dirty, rusty or painted metal better than MIG or TIG
- Excellent for outdoor work, farm repairs, structural steel and heavy sections
- Equipment is inexpensive and robust
- Widely used in NZ for rural and agricultural repairs
Limitations of stick
- More spatter and slag to clean up after each pass
- Harder to weld thin sheet metal without burning through
- Slower electrode changes interrupt workflow
- Requires more skill than MIG to produce consistently neat welds
Side-by-Side Comparison
| Feature | MIG | TIG | Stick |
|---|---|---|---|
| Ease of learning | Easy–Moderate | Difficult | Moderate |
| Weld quality/appearance | Good | Excellent | Fair–Good |
| Speed | Fast | Slow | Moderate |
| Portability | Moderate | Low | High |
| Thin metals | Good | Excellent | Poor |
| Dirty/rusty metal | Poor | Poor | Good |
| Typical NZ uses | Fabrication, trailers, gates | Stainless, aluminium, artistic | Farm repairs, structural |
| Shielding gas needed | Yes | Yes | No |
Materials and NZ Conditions
New Zealand's coastal environment means corrosion is a real concern. For stainless steel or aluminium marine fittings, TIG is usually the preferred process. For rural farm repairs in Southland or Hawke's Bay where portability matters, stick welding is hard to beat. MIG covers the middle ground for most suburban workshop projects.
Always check that your filler wire or electrode is compatible with your base metal. BRANZ publishes guidance on material selection and durability that can be useful when welding structural or weathering-exposed components.
Safety Essentials
All three processes produce UV radiation, fumes, spatter and extreme heat — never weld without proper personal protective equipment (PPE):
- Auto-darkening welding helmet rated to the correct shade for your process
- Leather gloves and a welding jacket or apron
- Leather boots — no synthetic materials near the arc
- Adequate ventilation — welding fumes are a serious health hazard; work outdoors or use extraction. WorkSafe NZ has clear guidance on fume exposure limits
- Keep a fire extinguisher nearby and clear flammables from the work area
- Never weld on galvanised steel without specialist respiratory protection — zinc fumes are toxic
When to Call a Professional
Some welding work in New Zealand must meet specific standards and should only be carried out by a qualified, experienced welder:
- Structural welding on buildings, decks or load-bearing elements must comply with the NZ Building Code and relevant standards. Depending on the scope, this may require involvement of a Licensed Building Practitioner (LBP)
- Pressure vessels, gas lines and anything connected to plumbing or gasfitting is restricted work under the Plumbers, Gasfitters and Drainlayers Act — contact the PGDB if you're unsure
- Trailer chassis and towbar welding that affects roadworthiness should be done by a certified welder and may require a WoF inspection
- Anything where weld failure could cause injury or property damage
If your project falls into any of these categories, it's well worth engaging a qualified local welder. You can find experienced welding tradespeople in your area on tradedirectory.co.nz.