How to use an argon gas cylinder
Updated: October 2026
The bottle is in the workshop, the regulator is in your hand, and the weld still depends on a nut that either meets the valve or does not. How to use an argon gas cylinder, for the bottles in this amazon.co.uk set, starts with the outlet, not with the flow knob. The [argon gas cylinder comparison](/hub/soldering-and-welding/argon-gas-cylinder) is where the eight listings are lined up. This page is the connection order and the points where you stop. Argon and argon mixes have no smell. HSE welding guidance treats them as an asphyxiation hazard in a confined space, separate from welding fume. Work where the air can move. Peter F. updated this on 18 October 2026. These are published handling points, not a bench test of your torch. A qualifying purchase can earn a commission at no extra cost to you.
The bottle is in the workshop, the regulator is in your hand, and the weld still depends on a nut that either meets the valve or does not.
The bottle is in the workshop, the regulator is in your hand, and the weld still depends on a nut that either meets the valve or does not. How to use an argon gas cylinder, for the bottles in this amazon.co.uk set, starts with the outlet, not with the flow knob. The argon gas cylinder comparison is where the eight listings are lined up. This page is the connection order and the points where you stop. Argon and argon mixes have no smell. HSE welding guidance treats them as an asphyxiation hazard in a confined space, separate from welding fume. Work where the air can move. Peter F. updated this on 18 October 2026. These are published handling points, not a bench test of your torch. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Outlet | Regulator | Stop if | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  SWP SWP WG/1368 60 L disposable | Not stated | Not in the box | The nut will not start by hand | 7.6 | about £17.99 | View offer |
| Alternative |  Gray Eagle Gray Eagle 8 L 82/18 | L 21.8 × 1/14 | Mini regulator in the box | You expected a BS 341 valve | 7.1 | about £169.99 | View offer |
| Best value |  Sealey Sealey MIGMIX2.2 430 g | M10 | Not included | Your nut is BS 341 No. 3 | 7.0 | about £57.17 | View offer |
On this page
Identify the outlet before the regulator touches it
UK industrial argon is BS 341 No. 3, a 5/8 inch BSP right-hand connection. None of the kept listings prints that outlet. Sealey’s MIGMIX2.2 and the four-pack state M10. Gray Eagle states L 21.8 × 1/14 and is the only listing with a mini regulator in the box. The empty steel shell states CGA580, a North American argon valve, with a 3/4 inch NGT inlet. The SWP disposable and both Sealey 60 litre bottles do not name a thread. Sealey says those small bottles fit Sealey and other welders or regulators. One SWP review described a fitting smaller than a normal regulator, then a 4 mm hose against an 8 mm hose on the welder.
Offer the nut to the valve by hand. If it will not start for a full turn without force, the pair is wrong. Gas Safe Consultants, writing about BS EN ISO 2503 regulators, make the BCGA point that the regulator should meet the valve without an adaptor. PTFE tape is not that adaptor. HSE guidance on gas welding equipment says not to use sealing tape on metal-to-metal bullnose joints. A thread that almost fits will damage the seat and can leak at the joint you have just hidden. The purchase decision, if you do not yet own the bottle, sits on the buying guide.
Fit the regulator, then open the valve slowly
Stand the cylinder upright and secure it so it cannot fall. BCGA storage practice is upright, restrained, ventilated, and full bottles kept apart from empty ones. A disposable on its side under a bench is a leak waiting for a knock. Check the valve outlet and the regulator inlet are clean and free of oil or grease. Oil on an inert joint is still contamination you do not want on a seating face. Do not repair a valve yourself. BOC tells customers not to repair valves and not to decant from one cylinder into another.
Wescol’s regulator instructions say to wind the adjusting knob fully out before you open the cylinder, so you are not opening against a set pressure. Tighten the nut by hand until it seats, then finish with the correct spanner. Do not extend the spanner with a tube. BOC’s handling note says inert outlets tighten clockwise. Stand to the side of the gauges rather than over them, and open the cylinder valve slowly. BCGA’s valve guidance is the same idea: open slowly, and do not leave the spindle hard against the backstop. One university checklist tells operators not to snift the valve. Wescol describes a brief snift to clear dust. The sources disagree, so this page does not make snifting a required step. If the valve is stiff, damaged, or the test date on a refillable cylinder is unclear, stop. Do not free a stuck spindle with mole grips.
Leak check with fluid, not with a flame
With the adjusting knob still backed off, listen and look. Then raise pressure only as far as you need to test the joint. HSE’s gas-welding guidance describes a leak check with a detergent solution, not a flame. BCGA makes the same point and prefers an ammonia-free leak fluid, because some fluids attack brass. Brush or spray the fluid on the cylinder-to-regulator joint, the hose connections and the torch connection. A growing bubble is a leak. A smear of fluid that sits still is not.
If the joint leaks, close the cylinder valve, vent the regulator through the flowmeter or torch in a ventilated space, and remake the connection once. If it leaks again, the nut, the seat or the hose is wrong. Isolate the bottle and do not weld. Tape wrapped over a weeping bullnose is not a repair. A disposable that empties itself overnight is often a valve left cracked, or a hose push-fit that never matched, which is the failure the SWP reviewer described with the 4 mm and 8 mm hoses.
Set the flow from the welder manual, not from a single number
BOC’s shielding-gas brochure uses about 15 litres per minute as an example for many jobs, and also offers about 1 litre per minute per millimetre of nozzle diameter as a guideline. Energas says MAG flow is often 15 to 20 litres per minute and that welders often use more, which can pull air into the shield and cause turbulence. A UK regulator guide from HF Welding Supplies calls 10 to 15 litres per minute common indoors, with the same warning that extra flow can entrain air. Those are published examples. They are not the setting for every torch in this comparison.
Read the welder manual for the nozzle and the process you are actually running. Set the flow with the torch trigger held, because a regulator gauge that moves with the valve shut is not the flow at the shroud. If you are on a 60 litre disposable, a setting copied from a brochure can empty the bottle before the bracket is finished. At 15 litres per minute, 60 litres is about four minutes as a rule of thumb. That arithmetic, and when a cartridge stops making sense, is on the disposable or refillable page. Which gas belongs on steel MIG and which belongs on TIG is on the argon or argon/CO2 page.
Shut the valve down, and know when the bottle was small
When you stop, close the cylinder valve. Then bleed the line by triggering the torch, or by the regulator maker’s vent method, until the gauges fall. Wind the adjusting knob out so the next open is not against a loaded diaphragm. HSE’s cylinder leaflet tells you not to leave cylinders in a poorly ventilated vehicle, to close the valve, and to secure the bottle. A disposable in a hot car is a pressure vessel, not a harmless aerosol, even when the gas volume is small.
If the gas runs out in a few minutes on a SWP or Sealey 60 litre bottle, the regulator is not automatically at fault. Those listings are small fills. SWP reviewers reported about 5 to 20 minutes. Sealey prints about one hour as approximate, beside a 100 g component. A bottle that lasts two or three minutes, as one Sealey argon reviewer reported, can also be a bottle that arrived empty. Weigh it against the stated weight if you can, and use the return route rather than assuming the flowmeter stole the gas. Call the supplier or a competent person if the cylinder is damaged, if you cannot read a test date on a refillable, if you are trying to get a DOT-marked CGA580 shell filled in the UK, or if the space is enclosed and someone could be exposed to an argon atmosphere. Do not decant, do not change a valve, and do not keep welding in a closed shed because the bottle was expensive.
Common questions
Which way does an argon nut tighten?
BOC’s cylinder handling guidance says inert-gas outlets tighten clockwise. That assumes you already have the correct outlet. It does not mean you should force a BS 341 nut onto an M10 disposable, an L 21.8 valve, or a CGA580 shell. Start by hand. If the thread does not pick up cleanly, the direction is irrelevant because the parts do not match.
Can I use tape if it almost fits?
No. HSE guidance on welding gas equipment tells you not to use sealing tape on a metal-to-metal bullnose joint. Tape can stop you seeing a leak and can put fragments into the regulator. Gas Safe Consultants also pass on the BCGA point that the regulator should meet the valve directly. If it almost fits, it is the wrong regulator for that bottle.
What flow should I set?
Use the figure in your welder manual for that nozzle and process. Published examples sit around 10 to 15 litres per minute indoors, and around 15 litres per minute in BOC’s brochure, with Energas often seeing 15 to 20 on MAG. More flow is not automatically a better shield. Extra gas can cause turbulence and pull air in. On a 60 litre disposable, a high setting also shortens an already short bottle.
How do I check for a leak?
With the cylinder upright and the adjusting knob backed off, open the valve slowly and wet the joints with a detergent solution or an ammonia-free leak fluid. Look for growing bubbles. Do not use a flame. If the leak continues after you have remade the joint once, close the valve, vent the regulator in a ventilated space, and take the bottle out of service. A second attempt with more tape is not a test.
The gas runs out in minutes. Is the regulator the fault?
Often it is the bottle. A rule of thumb at 15 litres per minute puts 60 litres at about four minutes, and SWP reviewers reported about 5 to 20 minutes. Sealey’s one-hour line on the 100 g disposables is marked approximate. A hose that does not match, as in the SWP review that contrasted 4 mm and 8 mm, will also waste gas or stop the weld. Check the fit before you blame the gauge.
When do I stop and call someone?
Stop if the thread does not match, if the valve is damaged or seized, if a leak will not stop, or if the test date on a refillable cylinder is unreadable. Stop if you need a UK supplier to fill the empty CGA580 shell, because that route is not established in these listings. Stop if the space is enclosed and someone could be exposed to an argon atmosphere. Those are supplier or competent-person jobs, not a tighter turn of the spanner.
Related pages
Sources
Public UK sources and the amazon.co.uk listings in this set, last checked on 17 October 2026.
- HSE INDG297, safe use of gas cylinders (retrieved 17 October 2026)
- HSE, asphyxiation hazards in welding (retrieved 17 October 2026)
- Carriage of Dangerous Goods Regulations 2009 (retrieved 17 October 2026)
- BCGA CP 44, storage of gas cylinders (retrieved 17 October 2026)
- BOC, shielding gas brochure (retrieved 17 October 2026)
- BOC, transporting and handling cylinders (retrieved 17 October 2026)
- BSI, BS EN ISO 14175:2008 (retrieved 17 October 2026)
- Boiswood, bottle connections (retrieved 17 October 2026)