Umm, some questions...
1. It seems like a lot of people use squirrel blowers, but you used a vent fan. Normally I see these mounted right side up or sideways to vent from a bathroom, say, but it looks like yours is upside down. I like the idea because it's a nice, low profile way of mounting the fan, but I wanted to verify that you're actually placing the fan upside down, so if I try to do just that I'm not being an idiot. Does the weight of the fan hold it in place, or is there some mounting hardware? And finally, does the fan resting in the round hole provide all the seal you need, or is something else going on in there too?
2. For those of us without a table saw, or other radial saw, what's the simplest, effective material to use for the cabinet? MDF? Some kind of plywood? I guess essentially I'd have to order the filter and blower, take all my measurements, then go to the home depot and have them do all the table saw cuts. Do they even do that?
Thanks, and sorry for being a total nube. When it comes to woodworking, I made a clock in shop class when I was 14, and that was it.
For blowers, it's all about the specs. If it can handle what the filter requires in terms of CFM and backpressure then it'll work.
The issues to keep in mind when picking a fan or blower are duty cycle and speed control. The duty cycle needs to be 100% and if any speed controller is used with it the motor needs to be of a type that can run with one.
For squirrel cage blowers, small ones usually have flanges that make mounting easy and for big ones they come with mounting hardware. I mounted mine like so:
The mounting hardware is the gray L-bracket:
It's a monster of a blower, so I extended the vertical supports (which are 2X3's) all the way to the bottom of main box. If I built it again I'd use rubber vibration dampeners between the blower and the box. The vibration is not too bad since it was balanced very well but every little bit counts (and it might make it a bit quieter; I wear ear plugs when using it but that's partly due to the horrible acoustics in most clean rooms).
I wired the blower to the end of an extension cord (I don't even remember why, probably for easy removal) which is plugged into a cord wired into an outlet box. If you open the top outlet cover there's a switch to turn on the blower and the bottom one has a single outlet that I plug my heat sealer or blender into (it's really handy to have an outlet there!).
For getting wood cut at the store, you might try 84 Lumber if there's one in your area. They specialize in lumber so they may do a better job with their cuts. Be sure to ask what it costs per cut.
And the little brass fitting seen in the top pic (it's to the right of the blower near the back) is a port for checking the pressure so I can tell when it's time to get a new one.