I have read some posts talking about building downdraft tables. I also read that a few different people wanted to use furnace blowers. This got me thinking. I do HVAC (Heating Venting Air Conditioning) for a living. I constantly getting old furnaces and swamp coolers. I could get a motor for free but not sure how to build one. I saw a few different designs on the internet but i thought talking to people who actually use one could help me design a very efficient one. What CFM would you recommend? Can you over power it? What would you do different than yours? Any suggestions would be appreciated. It would be nice if you suck so hard that it would hold down your piece of wood that your sanding. Talk to you soon