| Process / metal | Gas |
|---|---|
| MIG, mild steel up to 6mm | 5% CO₂ / argon |
| MIG, mild steel 4–12mm | 12% CO₂ / argon |
| MIG, thick structural steel | 20% CO₂ / argon, or pure CO₂ |
| MIG, stainless steel | 2% CO₂ / argon |
| MIG, aluminium | Pure argon |
| TIG, any metal | Pure argon |
| Cutting, brazing, heating | Oxygen with propylene |
What size cylinder?
A 10L does a hobby welder for months. A busy fabrication shop is better on 50L, or a 9- or 16-cylinder manifold pack. Every size is rent-free: you pay a refundable deposit once.