You know how sometimes, you have a big pile of sawdust to suck up, but you don't want to use a broom? How you'll pull out the shop vacuum? And how it'll breeze through the first bit of sawdust, then gradually choke and wheeze?
Even in normal use, a shop vac's filter gradually clogs with fine-grain sawdust. Eventually, the vacuum loses suction. The air filter isn't too hard to clean, but it'd be nice to keep it clean longer.
That's the idea behind dust separators: sawdust and air go into a cyclone. Sawdust is thrown to the outside edge and removed while the clean air exits to the vacuum in the middle.
A while ago, I built a cyclone separator, along with a radial fan to draw air through it. The system worked, but barely: the fan drew only a strong draft, and the separator leaked air through the sides.
Recently, I tackled the second problem. After considering weatherstripping, I decided to wrap the bottom of the cyclone separator in pipe insulation.
A test fit onto the 5-gallon collection bucket looked promising, so I tacked the insulation down with large-headed nails and tested with the shop vac.
The thing actually worked! When I plugged the shop vac into the outlet and held a handful of sawdust at the inlet, the sawdust was sucked inside and thrown into the bucket.
I need to test more, and see how much the separator separates versus passing through, but it works!
Next, I want to rebuild the impeller to handle more air. All together, I should have a capable little vacuum when I'm through.