I like reading both of y++ou and I'm no Pollyanna. Retro if you want an idea about what El is talking about, build a wood fire outside and stick a 3/4 inch metal water pipe into the center of the fire near the wood. Now bring a lit match to the other end of the pipe and you will lite a gas flame. The laser cut is the "fire" and the smoke tube is the pipe so you have to hope the fuel air mixture is not close to "stoiciometric" (probably spelled wrong) and that there is no spark or other ignition anywhere in the pipe! I think the laser especially with the air assist on is prime to create combustible gas as the flame is immediately blown out by the air assist leaving what has to be a high amount of combustible gas.

As long as were taking "flyers":
I think I will patent this idea before you guys beat me to it!: Laser beam hits wood in a closed vessel, gas is created, gas is moved to combustion area, power is made! hmmm.

Retro I'll need your machine to clean up what's left over in the exhaust stream.

The mixture from the laser must be extremely on the lean side of stoiciometric because the exhaust fan is pulling so much gas through the machine and that is why we have so few (anyone know of any?) laser explosions like in sawmills or flour mills. I wonder how the mixture would change over time if the "smokefan" stops during a cut and you had a continuous spark inside the case! I want some one else to be there, not me!