Argon or argon CO2 for welding
Updated: October 2026
The bottle in your hand says argon on the title, and the weld in front of you is a mild-steel bracket, a stainless offcut, or an aluminium bracket you hope to TIG. Argon or argon CO2 for welding is decided by the process and the metal, not by the word in the product name. The [argon gas cylinder comparison](/hub/soldering-and-welding/argon-gas-cylinder) is the price and specification table. This page maps each kept listing onto steel MIG, TIG, aluminium and stainless. Peter F. updated this on 16 October 2026 from supplier labels and the public description of BS EN ISO 14175, not from an assay of one Amazon bottle. A qualifying purchase can earn a commission at no extra cost to you.
The bottle in your hand says argon on the title, and the weld in front of you is a mild-steel bracket, a stainless offcut, or an aluminium bracket you hope to TIG.
The bottle in your hand says argon on the title, and the weld in front of you is a mild-steel bracket, a stainless offcut, or an aluminium bracket you hope to TIG. Argon or argon CO2 for welding is decided by the process and the metal, not by the word in the product name. The argon gas cylinder comparison is the price and specification table. This page maps each kept listing onto steel MIG, TIG, aluminium and stainless. Peter F. updated this on 16 October 2026 from supplier labels and the public description of BS EN ISO 14175, not from an assay of one Amazon bottle. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Gas | Process | Class | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  SWP SWP WG/1368 60 L disposable | Argon/CO2, ratio unstated | Mild steel only if an unknown blend is acceptable | Not filed as M21 | 7.6 | about £17.99 | View offer |
| Alternative |  Sealey Sealey MIG/ARG/100 argon | Argon, no CO2 stated | TIG and aluminium | I1 | 6.0 | about £31.68 | View offer |
| Best value |  Sealey Sealey MIGMIX2.2 430 g | 84% argon / 16% CO2 | Mild-steel MIG | M21 | 7.0 | about £57.17 | View offer |
On this page
Mild-steel MIG wants a CO2 mix, and the ratio has to be printed
Adams Gas points mild-steel MIG at an argon/CO2 mix and treats pure argon as a poor gas for that job. BOC uses an 80/20 mix as an M21 example and describes pure argon MIG on steel as unstable. BS EN ISO 14175 labels argon as I1. M21 is argon with more than 15% CO2 and up to 25%. Air Liquide’s ARCAL Force is the 18% example of that class. Sixteen, 18 and 20 per cent sit in the same family. Fourteen per cent sits just outside it. This page does not stretch 14% into M21.
Sealey MIG/MIX/100 at £32.11 states 80/20. MIGMIX2.2 at £57.17 and the four-pack at £192.57 state 84/16. Gray Eagle at £169.99 states 82/18. BricoLoco at £78.29 states 86/14. Those are the steel-MIG candidates, ordered by the CO2 share, not by how long they last. The SWP WG/1368 at £17.99 says argon/CO2 and never prints the percentages, so it is not 80/20 and it is not M21. You can weld mild steel with it only if you accept an unknown blend. Size and thread, once the gas is right, belong on the buying guide.
TIG and aluminium need argon, and this set barely sells it
Adams Gas and ESAB UK both start aluminium on pure argon, for MIG and for TIG. ESAB treats helium mixes as the exception for thick TIG, not as the first bottle. Adams uses pure argon for steel, stainless and aluminium TIG. Carbon dioxide in the shield is the wrong gas for aluminium and for TIG.
The only disposable sold as argon, with no CO2 percentage, is Sealey MIG/ARG/100 at £31.68. It states 60 litres and 100 g. The review line is 3.7 from 16. One of the two reviews in the file said the bottle arrived empty and lasted two or three minutes. The empty steel shell at £306.07 ships empty with a CGA580 valve. It is not a TIG supply until someone fills it, which these listings do not arrange.
Do not TIG aluminium with the 80/20, the 84/16, the 82/18, the 86/14, or the SWP bottle. If the regulator thread is what stops you using the Sealey argon disposable, that is a fitting problem on the how to use page, not a reason to substitute a steel-MIG mix.
Stainless is where the high-CO2 listings overclaim
BOC’s brochure says its Argoshield CO2 levels are too high for austenitic stainless, and it points to mixes kept under about 3% CO2 for L-grade stainless. That is supplier guidance, not a weld we ran. It conflicts with product text that offers a 14% to 20% CO2 mix for stainless.
BricoLoco’s 86/14 listing mentions stainless as well as carbon steel, low-alloy steel and iron. Fourteen per cent is far above that “under about 3%” point. Sealey’s 80/20 and 84/16, and Gray Eagle’s 82/18, sit in the same high-CO2 band: mild-steel MIG gases, or just beside M21 in BricoLoco’s case, not a low-CO2 stainless mix. None of the eight listings states a mix under 3% CO2. Say that BOC’s guidance and the listing disagree. Do not say a home test proved the bottle wrong.
What this set does not sell
There is no helium mix and no stated sub-3% CO2 stainless gas. There is no pure CO2 cylinder either, which Adams describes as the harsher option for budget steel MIG. You cannot infer those products from a title that contains “argon”, and you cannot infer a ratio for SWP. Forum experience of pure argon on mild steel is not the BOC description, and it is not a reason to buy MIG/ARG/100 for a steel sill when an 80/20 bottle is in the same price band. The empty CGA580 shell has no gas in it to classify.
For a short mild-steel MIG repair where an unstated mix is tolerable, the reviewed SWP bottle is the top pick. For a stated 84/16 disposable and more printed mass, Sealey MIGMIX2.2 is the best value mark, if the regulator is M10 and you accept no reviews. For TIG or aluminium, the only disposable candidate is Sealey MIG/ARG/100, and you should be ready for a small fill and a possible empty arrival. How many minutes the small bottles last is on the disposable or refillable page.
Common questions
Can I use pure argon for mild-steel MIG?
You can strike an arc, and some welders do, but BOC calls pure argon MIG on steel unstable and Adams Gas treats it as the wrong gas for that job. In this set the pure-argon disposable is Sealey MIG/ARG/100. The bottles with a printed CO2 share, from 14% to 20%, are the ones aimed at mild-steel MIG. Use the pure-argon bottle when the process is TIG or the metal is aluminium.
Can I TIG with the 80/20 bottle?
No. Sealey MIG/MIX/100 is 80% argon and 20% CO2, an M21-style mix for steel MIG. TIG on steel, stainless or aluminium is an argon job in the Adams guidance, which is I1, not a 20% CO2 blend. The same refusal applies to the 84/16, 82/18 and 86/14 bottles. CO2 in the shield is not a small impurity you can ignore on a TIG cup.
Is 84/16 the same sort of gas as 80/20?
They are the same kind of mild-steel MIG mix. Both sit in the band suppliers call M21: argon with more than 15% and up to 25% CO2. 84/16 has slightly less CO2 than 80/20. Gray Eagle’s 82/18 sits between them. They are not interchangeable with pure argon, and the bottle size is still a separate question from the percentage.
The SWP bottle only says argon/CO2. Which job is it?
It is an unstated mix in a small disposable, £17.99, with 4.6 from 160 reviews and reported weld times of about 5 to 20 minutes. Mild-steel MIG is the only process you might attempt, and only if you accept that the ratio is unknown. It is not a documented 80/20, and it is not a TIG or aluminium bottle. Do not invent the percentages from the title.
Does the BricoLoco 86/14 stainless claim match BOC?
No. The listing is 86% argon and 14% CO2 and the description mentions stainless steel. BOC points to under about 3% CO2 for L-grade austenitic stainless and treats higher CO2 Argoshield mixes as unsuitable for that metal. Fourteen per cent is a mild-steel MIG region, slightly under the M21 “more than 15%” line, not a stainless specification. The regulator is also a separate listing.
Do I need helium?
Not for the jobs these bottles can actually do. ESAB UK treats pure argon as the starting point for MIG and TIG aluminium, and helium mixes as the exception when thick aluminium TIG needs more heat. None of the eight listings states a helium content. If a procedure you already trust calls for helium, you will not find it by choosing the highest argon percentage in this set.
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)