I figured something like that was the case.
If you were experienced enough to have a plasma cutter then the question didn't make sense to me (of very little experience with cutting anything other than lumber).
I have done a ton of various stuff in my time in the Navy but I think the only time I worked with gases was argon in a radar wave guide to keep it from rusting the mirrored surface inside it.
Welcome to the forum and the
Addiction to molten glass!!!!
(Insert maniacal laugh here)