I have the 2 bag unit Harbor Freight calls "2 horsepower" connected to several tools with 4 inch PVC and blast gates. After several hours of use the shop was covered in very fine dust which many of these bag units can't filter out. I replaced the bag wiht a large industrial pleated paper filter which has stopped the fine dust problem. The system doesn't move enough air to capture all the dust from most of the larger tools. If I were to start over I would build the system described by Bill Pentz and exhaust the cyclone to the outside.


Harold Wilson
41 Chevy 3/4 Ton