Building an O2 concentrator for welding and vacuum tube work

Article note: Pressure Swing Adsorption is just neat. I'd been curious how hard it is to DIY one of these things since Zeolite 13x is pretty cheap and accessible, the concept is simple, and the pressures aren't _alarmingly_ high. Looks like the OxyKit folks saw that thought through. I'm kind of curious how - in the current post-COVID in the US market context - DIYing this thing competes with a cheap commercial one (which looks like it can get down into the $200 range) or maybe an electrolysis splitter on cost and practicality. I'm curious about some applications for a little concentrated O2, like the potential of using an O2 assist on a cutting laser.