Dust collectors serve a valuable purpose in stopping sawdust, a known carcinogen, from entering the air. However, as the dust bags fill up, their efficiency goes down. Most collectors are one stage, meaning everything is sucked into the dust bags. This includes chips and shavings and not just saw dust, which serve to clog the bag faster. A two stage collector passes the debris through the top of a container that allows the heavier debris to fall into the bottom of the container, leaving only dust to pass into the dust bags and increasing efficiency. With some easily obtainable items, you can make a single stage dust collector into a two stage version that will markedly improve dust collection.
Cut 2 holes in the lid of the trash can. Trace the outline of the pipe nipples on the lid and cut them out. The nipples should fit snugly in the holes. Place the holes 4 inches in from the side but opposite to each other.
Attach one elbow to each nipple and slide the nipples through the holes in the lid. Orient the elbows so that they face away from each other and also at a 90-degree angle to a line made by connecting the holes in the lid.
Attach the remaining 2 elbows to the other end of the pipe. These elbows should not face each other. Caulk the nipples in place so that they do not slide up or down or turn and to prevent air penetration through the lid.
Place the lid on the trash can and attach the dust collector hose coming from the dust port(s) to one elbow and the hose leading to the dust collector on the other.