Shielding gas
What gas do I need for MIG welding?
Quick answer
For MIG welding mild steel in Australia use an argon–CO2 mix — 92/8 (Argoshield-style) is the standard. 100% CO2 is the budget alternative with more spatter. For MIG on aluminium or stainless you need straight argon or a specialist mix respectively.
The decision table
| What you're welding | Gas | Flow |
|---|---|---|
| Mild steel | Argon–CO2 92/8 (or up to 80/20) | 12–15 L/min |
| Mild steel, budget | 100% CO2 | 15–20 L/min |
| Stainless | 98/2 argon–CO2 (or tri-mix) | 12–15 L/min |
| Aluminium | 100% argon | 15–20 L/min |
| Gasless wire | none — self-shielded | — |
Costs in Australia
Bottle hire vs refill: a D-size mix cylinder runs roughly $100–$130 a refill in most capitals, and hire contracts add an annual charge. Occasional welders often do better buying straight CO2 or running gasless wire; regular welders should price G-size hire against their L/min usage with our gas flow calculator.
This page answers the gas question only. For the whole process — settings by thickness, wire sizes, technique — read the gas section of our MIG welding gas guide. The hire-vs-swap maths is in welding gas cost in Australia, and observed refill prices by bottle size are on welding gas bottle sizes and prices.
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