On 15/11/2018 21:35, Cursitor Doom wrote:
On Thu, 15 Nov 2018 12:45:04 +0000, John Rumm wrote:

Most wire fed gas shield welding on steel uses CO2 as a primary
shielding gas rather than pure Argon or Helium. CO2 is classed as an
"Active" rather than an "Inert" gas, hence MAG rather than MIG.

Kind of struggling here to work out what use *any* non-inert gas would be
in a welding process. The very last thing you want is oxidisation!

It's normally for arc stability. It is normal to add a small amount of
CO2 to argon as pure argon has poor arc stability. O2/argon mixes are
for stability. Though only a couple of % of O2 is needed.

http://www.boc-gas.com.au/en/images/...351-411245.pdf

Yup, the more refined the process, the cleaner it needs to be usually.
If you want to weld through a load of rust and crap, there is not much
to beat stick!

True! Stick plasma blasts the living **** out of *every* contaminant
known to man.

Never really got on well with stick welding. MIG at high currents can
also weld through some surface coatings.