Danger, Danger, Danger, Will Robinson!!!
SPEEDRE,
Whatever route you choose, build or buy, remember to keep the motor isolated from the paint fumes (unless it is an explosion proof motor), otherwise bad bad things could/would happen. (flame2)If a large explosion did happen, you too could be "Lost in Space"!!!
I just purchased a used squirrel cage blower that I plan on converting to a dual purpose unit. I will box it in and install multiple filters to use it as a shop air cleaner. I will also use it to blow air into a "paint booth/room" with the motor isolated from the fumes, to provide positive pressure and vent through a window fitted with additional filters.
Randy,
I may not be good....
But I am S L O W!!