Thanks to Mr Thailkill and others for the inspiration. Of course gravity is the law and particles will sink. So I put the exhaust fan at the bottom and a return at the top. It is a false door than isolates my shaping room. Made out of Masonite. This little fan rocks. I bought some thin cloth and sewed it into a bag and then taped it to the exhaust of the fan.
I like it, how often do u have to empty the bag? Is this false door not a functioning door?