Thanks for the info and link, much appreciated!

I'd just like to point out that tape should only be used on tapered threads. If you need to put tape on a straight thread, then the fitting isn't seated correctly. Straight fittings don't seal on the threads. A tapered thread without tape is more likely to leak.

CO2 is added to pure argon to increase penetration, CO2 on its own will burn into the parent material, but will produce a brittle weld.

Some top end regulators as the Siegen one I have will fit both types of bottle.

Cant see why anyone would want to use anything other than the correct gas. I once used the argon bottle off the tig on the mig when the mig bottle ran out and the weld looked crap.My mate insists on using pub gas on his mig to save money and those welds always look like they have been frazzed.

Bob

all fuels are l/h (have a notch at corner of nuts) oxy and innerts are r/h threads
regulators should always be marked for type of gas and never mixed as its very dangerous (like acetlyene over pressurised out of its acetone will explode its a very unstable gas and can burn on its own with no oxygen!)
saying that co2 and argon can be swaped but purge out co2 for when using pure argon
pub bottles have a diffrent fitting to industrial cyl


also oxy equipment should be kept totaly oil and ptfe free as can burn internaly thats verry unsafe!

We have used the oxy gauge on the mig bottle before now with no problems.

bob