~$10, 10-minute (if that) cyclone separator

[CapnK]

Gonna make some dust? Tired of emptying out that shopvac, and cleaning/buying filters for it? Check this out - simply brilliant!

https://www.youtube.com/watch?v=OEdoTVsdXWU

[wolverine]

Wow that is a very simple cyclone, but it works.  The one I in my shop was much larger and a lot more $.  Very cool.

[Norman]

Simple and reliable, how can you beat that?

Especially good for picking up water, no water hits the filter.

[Tim]

Great idea, SailFar kinda guy. Can't wait to get home to make one.

[CapnK]

I rigged one up, even bought a brand new bucket and lid from Tractor Supply for ~$7. The 2 PVC elbows and 10'+ of rigid plastic bilge pump hose (@$1.5/ft) were another $18, so about $25 all in. That's ~$15 less than the cyclonic separator on Amazon by itself, & a bucket with lid is still needed.

Works well! Accidentally got aholt to a oil/grease mat when sucking up some bilge water and the suction of the 1.5 gal ShopVac with a 5' head out and up to the cockpit was still enough that it collapsed the bucket. :)
On another job had 3+ gallons of water in the big bucket and none was sucked into the ShopVac itself.

It will make an ungodly howling whistle noise from time to time if nothing is in the long hose, so keep the end handy and stick your finger across it to cancel out any harmonics that might get created.