As always "you get what you pay for". The school where I taught welding back in the early 20-teens, along with a few other technical subjects, had a professional-grade machine and the air pressure and volume to support it. DRY air is a must, and plenty of it. When it was working properly, it could cut a clean 1/16" kerf through 1/2" steel plate with no problem. It also worked well on aluminum. It also cost several thousand dollars.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!