Murf i just installed my ventalation and I used the 2 squirrel fans that were used to vent (or run the air conditioner I am not sure they were in a box with another cooling unit under the seat) i almost threw them away the travel trailer I am turning into my studio They were attached to the infloor air conditioner the suction is so good it holds foam board up to the hood when turned on. If you look in a junkyard for rvs or a used parts house you should be able to get one pretty cheap i just ran 2 duct tubes from eithar side of the blowers to a homemade hood and then vented off the back of the box it was in to a window in the trailer. the whole thing cost me 40 bucks maybe and being a single mom every penny counts, a local guy who teaches and has his own studio told me it would be good for any kind of torch it was really too strong for me with my hot head now
If I can I will get a shot of it tomorrow on the camera I saw some other fans and stuff on ebay that you could make your own and on artglass answers there is a thread on how to build your own hood or torch cabinet Good Luck