MIG Welding: The Complete Australian Guide

What is MIG welding?

MIG welding (GMAW — Gas Metal Arc Welding) — a continuously fed wire electrode melts into the weld pool under an argon-CO2 shield. It's the easiest process to learn and its natural territory is beginners, speed, sheet steel.

MIG is where most Australian welders start: the machine feeds the wire, you steer, and usable beads arrive within an hour of striking your first arc.

How the process works

An electric arc between the electrode and the work delivers intense, localized heat; the molten pool is protected by an argon-CO2 mix (Argoshield-family) or 100% CO2 — without that shield, air makes the weld porous and brittle. Beyond the physics, the operator controls heat, travel speed and position; the process rewards consistency over talent.

Settings by thickness

Equipment and consumables

What you need beyond the machine: an argon-CO2 mix (Argoshield-family) or 100% CO2 where applicable, filler matched to your material, and the safety kit that never gets discounted — helmet, gloves, ventilation. In Australia: Most Australian hobby MIGs run from a standard 10A power point; 15A circuits unlock the 200A+ class for structural work.

Gas and wire choices

Run an argon-CO2 92/8 mix (Argoshield-family) for general steel — it's the Australian counter standard for good reason: stable arc, low spatter, forgiving thin-sheet behaviour. 100% CO2 saves money on refills at the cost of spatter and harshness on thin work. Wire: 0.9 mm er70s-6 covers 90% of hobby and light-trade jobs; 0.8 mm for sheet under 1.5 mm, 1.2 mm for sustained thick work.

Material by material — steel, stainless, aluminium, gasless wire — the decision table with flow rates is in what gas do I need for MIG welding?. Bottle sizes, hire vs swap and what a refill actually costs are in buying welding gas in Australia.

Technique fundamentals

• Stick-out 8–10 mm — the most common beginner fault is welding from too far away
• Push 5–15° for thin material and visibility; pull for penetration on thicker steel
• Listen: a steady crackle means the volt/wire-speed pair is matched
• Watch the pool, not the arc — the pool tells you speed and heat

Common mistakes

• Stick-out too long — keep 8–10 mm from nozzle to work for a stable arc
• Travel too slow on thin sheet, burning holes instead of building a bead
• Wrong wire size for the job — 0.9 mm covers most hobby work in Australia
• Gas off or breeze blowing the shield away — porosity is a gas problem 9 times out of 10