DC Tig with Helium - Beginnings...

[backpurge]

Is there a simple(ish) conversion factor to apply? I've just given myself a headache trying (and failing?) to work it out using relative densities... 5 litres/min argon turned into ~11.5 with helium

In answer to your question HR, no there isn't a simple conversion as it isn't linear but as a rule of thumb to get 5ltr/min coming out of the torch you would set the following for various gas mixtures
100% He - 2ltr/min
75%He + 25% Ar - 3ltr/min
50%He + 50% Ar - 4ltr/min
25%He + 75%Ar - 4ltr/min

 

[steviec_lj]

Very useful info there BP.

So I'd need to set my flow gauge to 2lpm, yes?

 

[backpurge]

Very useful info there BP.

So I'd need to set my flow gauge to 2lpm, yes?

For TIG welding ally I would probably use a slightly higher flow rate, remember you will most likely be creating a much larger weld pool than you would if you were welding steel so I would set your flowmeter around the 4 ltr/min mark and see how it goes, the condition of your tungsten is always a good indication of gas flow

 

[Richard.]

In answer to your question HR, no there isn't a simple conversion as it isn't linear but as a rule of thumb to get 5ltr/min coming out of the torch you would set the following for various gas mixtures
100% He - 2ltr/min
75%He + 25% Ar - 3ltr/min
50%He + 50% Ar - 4ltr/min
25%He + 75%Ar - 4ltr/min

Super info BP.