Argon Tank Sizes and Prices: Cylinder Guide for Welders

Pure argon is the workhorse gas for TIG welding on all metals and MIG welding on aluminum. Picking the right tank size comes down to how often you weld and how far you’re willing to drive for refills. Buy too small and you’ll spend half your time at the gas supplier. Buy too large and you can’t move it without a forklift.

Argon Cylinder Size Chart

All sizes below are for high-pressure gas cylinders filled to approximately 2,015-2,640 PSI. These are DOT-rated steel or aluminum cylinders.

Prices are approximate ranges based on current market conditions. Actual prices vary by region, supplier, and new vs. used condition. Cylinder prices have climbed in recent years due to steel costs and regulatory requirements.

Cost Per Cubic Foot

Larger cylinders cost more per fill in absolute terms but significantly less per cubic foot of gas. This is the most important number for evaluating value.

Moving from a 20 CF tank to an 80 CF tank cuts your per-CF cost nearly in half. Going to 250 CF cuts it by almost 70%. The message is clear: buy the largest tank you can physically handle and afford.

How Long Each Size Lasts

Arc time depends on your flow rate. TIG welding typically runs 15-20 CFH. Aluminum MIG runs 25-35 CFH.

For a hobby TIG welder spending 3-5 hours per week in the shop with a 15% arc-on factor, an 80 CF cylinder lasts roughly 2-4 months. A 125 CF cylinder stretches that to 3-6 months.

Which Size to Buy

20-40 CF (R-size): Only if portability is the priority. These are backup tanks, field service tanks, or tanks for a small portable TIG welder you take to job sites. They empty too quickly for regular shop use.

80 CF (Q-size): The standard entry point. One person can carry it, it fits on any welding cart, and most gas suppliers have 80 CF cylinders in stock for immediate exchange or same-day fill. If you’re new to gas welding, start here.

125 CF (S-size): The best value for regular welders. The refill cost increase over 80 CF is modest (roughly $10-15 more), but you get 56% more gas. At 80-95 lbs full, it’s still manageable for one person with a cart. This is the sweet spot for small shops and active hobbyists.

250 CF (K-size): For shops that weld daily. At 140-165 lbs, you need a cylinder cart and possibly a hand truck for loading into a vehicle. The per-CF cost savings are substantial. If you’re filling an 80 CF cylinder every 2-3 weeks, a 250 CF tank reduces your refill trips by 65%.

330 CF (T-size): Production shops and welding schools. These stay on a cart and rarely move. Maximum gas volume at the lowest per-CF cost. Justifiable only if you’re burning through 250 CF cylinders in under a week.

New vs. Used Cylinders

New cylinders come with a fresh hydrostatic test date (10 years for steel DOT 3AA). They’re guaranteed free of damage, arc strikes, or corrosion. You pay full retail.

Used cylinders save 30-50% but require inspection. Verify:

• Hydro test date is current (stamped on the cylinder shoulder)
• No dents, gouges, or deformations in the shell
• No arc strikes (bright melted spots on the cylinder wall)
• No heavy corrosion or pitting
• Valve operates smoothly without grinding or sticking
• No gas company ownership stamps (avoid leased cylinders sold improperly)

Good sources for used cylinders include local welding supply shops (they often sell trade-ins), online classifieds, and shop closure auctions. Avoid anything that’s been painted over the markings since you can’t verify the test date or specs.

Aluminum vs. Steel Cylinders

Most welding cylinders are steel (DOT 3AA). Aluminum cylinders (DOT 3AL) exist and have one major advantage: weight. An aluminum 80 CF cylinder weighs roughly 20 lbs less than its steel equivalent.

Trade-offs with aluminum:

• Cost more to purchase (20-40% premium over steel)
• Require hydrostatic testing every 5 years (steel gets 10 years with star stamp)
• More susceptible to damage from impacts and drops
• Can’t be used for all gas types (check DOT markings)

For a shop tank that sits on a cart, steel makes more sense. The weight savings of aluminum matter most for portable tanks that travel frequently.

Regulator Requirements

Pure argon cylinders use CGA 580 connections. Any regulator rated for CGA 580 and inert gas service works. If you’re using the same cylinder for TIG, make sure your regulator has a flowmeter calibrated in CFH, not just a pressure gauge. Flow rate accuracy matters more for TIG than MIG because TIG runs at lower flows where small variations have a bigger impact on coverage.

A decent single-stage regulator with a flowmeter runs $50-100. Dual-stage regulators ($100-200) provide more consistent flow as cylinder pressure drops, which matters most on large cylinders used over long periods.

Safety

Argon is non-toxic, non-flammable, and chemically inert. The only hazard is oxygen displacement. Argon is 38% heavier than air and pools in low spots: pits, tanks, trenches, and below-grade work areas. In an enclosed space, argon can displace enough oxygen to cause asphyxiation without any warning odor or sensation.

Cylinder safety basics:

• Chain upright at all times. A falling cylinder can shear its valve and become a high-pressure projectile.
• Valve cap on during storage and transport.
• Never expose to temperatures above 125F (52C). Park your truck in the shade if a cylinder is in the bed.
• Test connections with leak detection fluid after every cylinder change.
• Close the valve when not actively welding. Bleed the regulator by opening the flow briefly after closing the valve.
• Store away from combustible materials, though argon itself won’t burn or support combustion.