Shielding gas
How long does a gas bottle last when welding?
Quick answer
At a typical MIG flow of 12–15 L/min, an E-size bottle (~4,600 L) gives roughly 5–6 hours of arc time — several weeks of hobby welding — while a G-size (~9,500 L) doubles that and a D-size (~1,800 L) suits occasional repairs. Real-world cylinder life is arc time × flow, so duty cycle decides the calendar: at 30% arc-on, each workshop hour drinks about 250 L.
Doing the maths
| Bottle (argomix) | Free gas | Arc time @14 L/min |
|---|---|---|
| D-size | ~1,800 L | ~2.1 hours |
| E-size | ~4,600 L | ~5.5 hours |
| G-size | ~9,500 L | ~11 hours |
Making it last
- Trigger off between tacks — gas flows only while welding on modern sets
- Cut flow to 10–12 L/min indoors with good screens
- Fix leaks: soap-test regulator fittings when a bottle empties fast
- Post-flow 3–5 s protects the weld; longer than that is waste