I do all my own casting in my basement shop. I took a large squirrel cage fan from a gas fired furnace and mounted it to the ceiling in my shop. I closed off all of the intake ports as best I could with fibre board, and have one with a quick detach port. I cut a six inch hole through the wall of the house to my back yard and installed a piece of black stove pipe. My shop is 22' long, and when I turn on the fan, and light a match at the far end of the shop, the smoke makes a bee line for the fan. This is also good for when I'm using finishing solvents. I have to open the shop window at the other end of the shop just an inch or so, or the exhaust fan will extinguish the house's gas hot water tank.
About twice a year, I turn on the fan, open it's door, and use my air compressor and a long tube attachment to send all of the dust that accumulates in the rafters outside. I used to think the dust was from our cat, but shes long gone now, and the dust still keeps accumulating. Must be something else causing it.