Originally Posted by
David Somers
I may be misinterpreting Dan's thoughts (apologies if I am Dan), but I think he was objecting to outside air being brought directly into the laser from outside. A second 4 or 6 inch hose coming off your machine connected straight to outdoors. As your blower moves smokey air from the laser to the outside, air is replaced directly from outside through the second hose, through which you get cold, moist air brought straight into the laser. I think that was his concern. If your laser is replacing blown air from the ambient air in your shop the outside air that is seeping in to replace your blown out air has a chance to warm up some and the moisture coming in with it dissipates through the room so the impact inside the laser is much less.
His preference was not to blow the machine's air outside at all, but instead to run it through filters and feed it right back to the shop so it was not impacting your heating bill, and not sucking colder, moister air directly into the laser.