buffo pinged me about this thread.
i built a 60W cnc co2 laser cutter a while back. it is by no means portable or safe for the general public. the fundamentals are pretty basic, but they run on roughly 20kv, have water flowing through the tube, and the beam is invisible. plus, there's endless amounts of fiddling to keep things in alignment, clean, and level. it's absolutely a labor of love, and i don't regret it in any way. if you plan on bringing a cutter around public use, I would absolutely encourage you to go with a commercial and fda / cdrh legal system.... you do not want a lawsuit.
having said that, i'm happy to answer any questions you might have. here's a little footage of my system in action.
suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.