In article ,
tillius wrote:
Has anyone tried using a water filled container as a filter for dust
collector exhaust air? Sort of like a bong in reverse - the dirty air
gets exhaused under water and bubbles up to the top, where the water
will filter out all the sub-micron dust?

I'm just looking for a cheapskate alternative to 0.5 micron filter
bags.

Any suggestions, comments or other ideas?

"Rainbow" makes/made a vacuum cleaner that works in exactly that fashion.
With only 'so-so' effectiveness at keeping the really fine stuff down.

I'd see _practical_ difficulties with a dust-collector -- due to the
_volume_ of air involved, and the need to have _little_ bubbles. Which
translates into the need for a non-trivial area of bubble-generation.
WAG says probably 'several' square _feet_ per 1000 CFM capacity.

Not to mention the static-pressure requirement. A water filter induces
A back-pressure of _at_least_ 1-1/4 PSI, per inch of water depth. the
effectiveness of particle removal goes up as (a) the bubbles get smaller,
and (b) the depth of the water gets greater. To scrub _small_ particles,
you may need several inches of water, _and_ some 'mesh' layers (to break
up larger bubbles that have formed by coalesense).

With proper consideration of design, one can probably cobble up something
that will work. It likely won't be simple, nor inexpensive (regardless of
how 'cheap' it's built , however.