[bowleggid]

I'm told that the welding suppliers in Colorado (Denver - North) sell "industrial" grade helium, which is also balloon grade, at 99.5% He. Is this pure enough for use with aluminum?? -- I installed a Y on my Square Wave & am "sneaking a little in" like Roy & Jody do -- floating the ball -- adding a small amount to Argon to get the enhancing effects of He.
I've only used UHP Helium so far - & I love what it does for welding aluminum - but it appears to be much more difficult to find. What is the minimum acceptable percentage of helium purity for welding aluminum in this manner -- or if I wanted to use only He as a shielding gas (no Ar) -- what's the minimum purity?

[pgk]

I would just get the industrial grade He and you will probably find that you will want to mix Argon with it, pure Helium is much harder to establish a arc than say a 50-50 mix. I have a smith mixer and usually set mine from 25-he to 75-Ar or 30-he to 70-Ar. My local welding supply contact told me that the only difference between UHP and industrial grade Helium is they have to verify the contents and purity of UHP because of the fact that it is also used in the medical field.

Pete

[LtBadd]

The different grades of helium

[cptjackm]

The different grades of helium

Thanks for that HE link, very helpful.
Jack

[Oscar]

Yea, I was about to say, 99.5% would be pretty low indeed for industrial. I had always read 99.995% is industrial, which is 50ppm impurities.