TIG shielding gas alternatives

[PlasmaGuy]

I am TIG welding stainless and am using 100% Argon. I will run out of my argon over the weekend.

I have two cylinders of an argon + helium blend that I use on stainless using MIG.
Will this blended gas work with TIG welding stainless? The term "heli-arc" is synonymous with TIG welding but I am un-sure if this will work.

Thanks guys!

Tom

[bob_e95482]

It should work just fine. The arc will be hotter with the helium blend, so lower your settings.

[PlasmaGuy]

Thank you Bob!

That's what I was wanting to hear

[USMCPOP]

Is that gas a tri-mix with CO2?

[PlasmaGuy]

Argon and helium only.

[GT6Steve]

Bob, can you explain to a novice why the arc will be hotter with Helium? Less dense gas allows a stronger arc??

[Meltedmetal]

From "The Miller Tig Handbook" available in pdf format on this site.- Meltedmetal

Unlike argon, helium has high thermal conductivity. Due to
this higher thermal conductivity, the arc column expands,
reducing current density in the arc. The arc column will
become wider and more flared out than the arc column with
argon shielding gas. Figure 4.13 illustrates the two arc
columns. The more flared out the arc column, the more work
surface area is being heated. The heat at the center of the arc
can move more readily downward toward the colder metal
at the bottom of the workpiece. This results in a deeper
penetrating arc. Figure 4.13 also illustrates the resultant weld
beads and the difference in penetration produced by argon
and helium.

[PlasmaGuy]

update

Well I tried the argon & helium mix. I works but is much hotter.

I slipped up and didn't realize I was on my last bottle.

I am definitely used to 100% argon.

Thanks,

Tom