Effect of Gas on the Arc

[Cippee]

This is an odd thread to start, however. The other day I forgot to turn on the argon and when I tried to start an arc the hf just buzzed and I realized I didn't have gas. It got me think most people don't think all the time about how the gas helps the arc to form and be stable. Hence why helium is about a 1/3 hotter than argon. If you have an old tungsten try welding with pure co2 for a laugh. co2 does not like to let the arc travel through it. I believe one reason is because it is not an inert gas and has more interaction with the arc. Also you know if you don't preflow the argon the blast of pressure can mess with the arc. Well at least it you have a crappy regulator like me. You guys know alot more than me so I'm interested in hearing your ideas about this.

[Ray]

Well, not sure if you realize what can you opened up.
I could, (and maybe should) write a book.

But the very short answer is in Tig welding the gas is the arc….

The argon is ionized and becomes the conductor, what we perceive as a flame like arc is actually an envelope of ionized argon conducting current.
Argon is used because it’s easy to ionize because of the number of electrons in the outer shell of the atom, it’s inert and won’t react with the molten metal and it's cheap and easy to produce.

[Cippee]

I was hoping to stir up something. I learn something everyday on this forum. I know in mig welding people don't like to use pure co2 as much because it is a harsher arc because like you said it doesn't ionize like argon does.

[Cippee]

Well I guess this thread doesn't peak as much interest as I hoped it would. Oh well.