Oh also.
The fans I use are 6" air hockey fans... they are really loud at full voltage, but at half voltage (in series) they are quiet and still move some air.. going to use a variable controller on them. I have 8 of these monster fans (110V AC). I had a good deal on them, but that's over now..
Still can get them occaisonally though
The cases are all metal, but the blades are hard platic.. VERY nice bearings though... well built fan.
I got them at a furniture (of all kinds) salvage shop in northern Arkansas.
Rich W.