Deep Dive
Welding Gas Bottle Sizes & Prices in Australia (2026)
Every welding gas bottle size explained with observed Australian prices: D vs E vs G capacity, how long each lasts, and BOC, Supagas and Coregas refill and plan prices side by side.
Welding gas pricing in Australia is opaque. Most suppliers don't publish prices — you have to call. This guide changes that: observed prices by bottle size (D, E, G) and supplier, the specs behind each size, and how long each one lasts. For the annual hire-vs-swap-vs-buy decision, read our companion guide to welding gas cost in Australia; for which gas goes in the bottle, start with what gas do I need for MIG welding?
Bottle Sizes Explained
Australian welding gas bottles follow a standard sizing system. The letter doesn't stand for anything meaningful — it's just the convention.
At 10L/min flow rate (standard for MIG):
| Size | Continuous Weld Time | At 2 hrs/week | At 4 hrs/week | At 8 hrs/week |
|---|---|---|---|---|
| D | ~4 hours | ~2 weeks | ~1 week | ~3 days |
| E | ~8 hours | ~4 weeks | ~2 weeks | ~1 week |
| G | ~16 hours | ~8 weeks | ~4 weeks | ~2 weeks |
Observed Prices (August 2026)
From our live gas price tracker — the only structured pricing data available for Australian welding gas:
BOC doesn't publish Argoshield mix pricing online. Community reports suggest mix pricing falls between pure argon and CO2 — roughly 10-20% below pure argon. For exact pricing, contact BOC or a competitor directly.
Supagas: Community-reported refill prices are significantly lower than BOC (D-size argon ~$47 vs BOC $108). However, availability is limited outside metropolitan areas.
Coregas (Trade N Go): Rent-free swap program. You buy the bottle outright (~$300 for D-size) then swap empty for full (~$140-145). No ongoing rental. Best for welders who want to avoid rental commitment.
Air Liquide: Pricing not publicly available. Generally competitive with BOC for trade accounts.
| Gas | Size | Annual Plan | Refill | 3-Year Plan |
|---|---|---|---|---|
| Argon (pure) | D | $108 | $108 | $169 |
| Argon (pure) | E | $199 | $199 | $239 |
| Argon (pure) | G | $219 | $219 | $329 |
| CO2 (industrial) | D | $79 | $79 | — |
| CO2 (industrial) | E | $149 | $149 | — |
| CO2 (industrial) | G | $199 | $199 | $269 |
Rent vs Buy vs Swap: The Real Math
The per-usage-profile comparison (monthly, quarterly, twice-a-year welders) is worked through in full in Buying Welding Gas in Australia. Below is the per-supplier plan detail those numbers come from.
You pay an annual plan fee plus refills. The bottle belongs to BOC.
Best for: Regular welders who want predictable costs and don't want capital outlay.
Annual cost (argon, D size, moderate use):
You buy the bottle (~$300 D-size), then swap empties for full ones (~$140-145 each swap).
Best for: Commitment-phobes and low-frequency welders. No rental ticking away.
Annual cost (argon, D size, moderate use):
Break-even vs rental: ~18 months (at which point rental would have cost $540 × 1.5 = $810 > $860)
Actually, rental is cheaper if you're welding consistently. Buying only wins if you weld so rarely that months pass between refills and the annual rental fee feels wasted.
Skip gas entirely with flux-cored wire.
Best for: Outdoor welders, occasional users, rural/remote.
Annual cost: ~$70-150 in wire (depending on volume). No gas at all.
See our gasless MIG guide for the full comparison.
- Plan: $108
- Refills (4/year): $432
- Total: $540/year
- Bottle purchase: $300 (one-time)
- Swaps (4/year): $560
- Year 1: $860 | Year 2+: $560/year
The Decision Matrix
| Your Situation | Recommended | Why |
|---|---|---|
| Welding < 2 hrs/month | Gasless | No rental eating you alive |
| Welding 2-4 hrs/month | D-size rental | Cheapest per hour at this volume |
| Welding 4-8 hrs/month | E-size rental | Fewer refills, better value |
| Welding > 8 hrs/month | G-size rental | Economy of scale |
| Outdoor/windy always | Gasless | Gas won't work in wind |
| Aluminium or TIG | Pure argon, E minimum | No alternative |
Hidden Costs to Watch For
- Delivery fees: BOC charges for delivery to non-account holders. Pick up from a gas centre if possible.
- Deposit/bond: Some suppliers require a bond on top of the rental (refundable when you return the bottle).
- Minimum order: Some trade suppliers won't sell to walk-ins without an account.
- Contract lock-in: BOC's 2 and 3-year plans have better rates but lock you in. If your welding needs change, you're still paying.
- Late return fees: Return your bottle on time when your plan expires, or fees continue.
How to Get the Best Price
1. Ask for trade pricing. Even if you're a serious hobbyist, some suppliers offer better rates for regular customers.
2. Compare across suppliers. BOC is not always cheapest. Supagas and Coregas often undercut them.
3. Consider a larger bottle. G-size has better cost per cubic metre than D-size — if you can handle the weight.
4. Check for promotions. BOC periodically offers plan discounts or waived fees.
5. Factor in travel. The cheapest supplier isn't cheapest if you're driving 45 minutes each way for a refill.
Frequently Asked Questions
How much does a full D-size argon bottle weigh?
About 35kg total (20kg bottle + ~15kg gas at pressure). Manageable for one person.
Can I use my own bottle?
Only if it's currently certified and the supplier accepts customer-owned bottles. Most major suppliers require you to use their bottles on their rental plans.
What happens if my bottle runs out mid-weld?
The weld will go porous immediately — you'll see it in the bead. Stop welding, close the valve, and arrange a refill or swap.
Is it cheaper to buy gas from Bunnings?
Sometimes, for a D-size. Bunnings now sells Coregas Trade N Go swap bottles — D-size MIG mix at $118 plus a $200 refundable deposit, and E-size argon at $184 — with no annual rental. There are no G-size bottles and no rental accounts, so regular welders still need BOC, Supagas, Air Liquide or Coregas direct. The full stock list and per-litre comparison: does Bunnings sell welding gas?
Do I need a licence to buy welding gas?
No licence is required for standard welding gases in Australia. You need to be over 18 and the supplier will record your details for safety compliance.
Frequently asked questions
How long does a gas bottle last when welding?
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.
How much does welding gas cost in Australia?
Refills of argon-CO2 mix cost roughly $100–$140 per D-size bottle and $150–$200 per G-size in Australian capitals, plus annual hire if you rent rather than swap-and-own. Straight CO2 is cheaper per refill; pure argon similar to mix. Budget by litres: mix works out around 2.5 cents per litre.
What is pure argon used for in welding?
Pure argon is used for TIG everything (helium mixes for thick sections); MIG aluminium, typically at 8–12 L/min TIG. The default TIG shield; also the base of most mixes
What is argon-CO2 mix used for in welding?
Argon-co2 mix is used for MIG on steel (Argoshield-family 92/8 to 80/20), typically at 12–15 L/min. More CO2 = deeper penetration, more spatter; 92/8 is the Australian hobby standard
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