I have been experimenting with the 18mm glass roasting tube to see why it produces such smooth vapor and have determined that I am creating a glass fluidization chamber. http://en.wikipedia.org/wiki/Fluidization The Volcano, Herbalizer, and Cloud also utilize a fluidization chamber arrangement which is one of the reasons they work so well. Air corn poppers and coffee roasters use fluidization to ensure uniform roasting temperature. It makes sense that it would work well for vaporization since all you are doing is roasting a herb. Getting the air to spin like a corn popper should provide the most effective extraction (need to work on that). The roasting tube is the second half of a vaporizer and every bit if not more important than the heat unit. A fluidizing tube will improve the effectiveness and flavor of the vaporizer system. A glass chamber is the most ideal for taste.