Shielding gasses for TIG welding Argon is not the only shielding gas used for TIG welding…just the most common and versatile. Argon will usually get the job done. But there are times when some helium mixed with argon makes a world of difference. Especially if you are using a small inverter TIG welder that is limited to around 200 amps.
100% Argon – is the most often used and coolest gas ..the best all around gas. 75% Argon/25% Helium – even 25% helium will make a big difference when welding aluminum that is thicker than .063". Anything under .063" thick and helium is unnecessary.
50/50 argon/helium—awesome for thick aluminum and magnesium 75% Helium/25% Argon – Awesome for thick aluminum castings… puddles really quick and welds cleaner than 100% argon. Also good for welding bronze and pure copper on DCEN.
100% Helium – . Hot but Hard to start the arc on A/C.
Did you know that you can use UHP helium (ultra high purity) and weld aluminum on DCEN? I have not been able to make this work on dirty castings but on something like an injection mold or aluminum fixture made from new fresh aluminum plate that is not heavily oxidized , it works great and does not heat the base metal nearly as much as welding on A/C.. takes a lot less amperage too.