toms73novass said:
I tried a water trap idea and because of the bubbling of the water the tube that went to the shop vac carried water and ended up putting a gallon of water into the shop vac after about 30 min.
I was planning on building one of these, but i came up with a design variant, that might solve the problem of water in the vaccum. I haven't tried it yet, so i can't guarantee it will work.
Instead of having the inlet tube stick down into the water, drill a large hole in the side of the bucket, right near the top. Drill the hole angled so the inlet air comes in against the side of the bucket. (tangent to the diameter) Point it slightly downward as well, and glue it in place. The exit hose to the vaccum should be in the center of the lid.
When you turn on the vaccum, the air rushing in should cause the water in the bucket to start rotating, and the centrifugal force of the rotating water will eventually cause it to ride up on the walls of the bucket in a thin layer, right where the air (and dust) is entering. the centrifugal force will mix the dust and water, and this force will also keep the water away from the exit hose in the center of the bucket.
This is the principle of how an industrial cyclone separator works (and those new fancy expensive bagless vaccum cleaners), except with the addition of water
If someone gets around to building one of these before i do, let me know how it works.