Gunner Asch wrote:
Use of a "gas lens" helps when you need a longer tungsten.
If you've never used one, I highly recommend it. You can see
the difference by holding the torch at arms length with a bright
light behind you, and checking the shadow of the torch when you
trigger the gas. Argon is so dense, it makes a visible shadow
due to the refraction of light at the boundary between air and
Argon. You can see the pronounced turbulence with the standard
torch and cup, and a much more laminar flow with the gas lens.
They will save you their cost in Argon on your first tank, as
you can often cut your Argon flowrate in half and still have
less contamination of the weld.

Jon