Which gas for TIG welding? Argon or a mix
The shielding gas keeps oxygen and nitrogen out of the weld pool. Which gas you choose depends on the material. Here you can read what suits which job and how much gas you need.
Which gas for TIG welding?
100% argon is the standard. It works for steel, stainless, aluminium and titanium. It is calm, gives a stable arc and is available everywhere. Not sure what to choose? Then argon is the right answer.
Argon with helium can make sense for thick aluminium and for copper. Helium puts more heat into the weld pool, so you weld faster or can handle thicker material. It is more expensive and the arc starts less easily.
Argon with a little hydrogen is sometimes used on austenitic stainless, such as 304 and 316. It gives a hotter weld pool and a cleaner seam. Do not use it on steel, ferritic or duplex stainless, because it can cause cracking there. In doubt? Stay with argon.
Gas for MIG/MAG (with CO2) does not belong with TIG. It damages the tungsten electrode quickly.
How much gas do you need?
As a starting point, use about 6 to 12 litres per minute, depending on the cup size and draught. Too little gas gives a black weld, too much makes the gas flow turbulent so it draws in air.
Do not forget post-flow
Let the gas keep flowing for a moment after you stop the arc, so the weld and the electrode cool under gas. On stainless and titanium this is extra important. Read how to get good gas coverage.
Common mistakes
- A gas cylinder that is almost empty: the pressure drops and the gas flow becomes irregular.
- A leaking hose or connection: a black weld with pores is often the result. See TIG welding problems and how to fix them.
- Too large a cup or too large a distance: the gas mixes with air. Read how to choose the right cup size.
Parts that help
With good cups and a gas lens you get more out of your gas. Not sure which parts fit your torch? Use our selection guide or send us a message via the contact page.