Easy Dust Separator

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Project by SteveMI posted 07-23-2009 10:25 PM 57321 views 144 times favorited 20 comments Add to Favorites Watch

This is the build of a dust separator. I needed something to pull the dust away from power tools that had a 2” or smaller hose attachment. My 1.5 hp, 6” hose double chamber vacumn didn’t pull enough suction when necked down to the smaller diameters.

I had downloaded the Bill Pentz spreadsheet that generates dimensions for building your own to his design, but my skill with metal aren’t adequete. Was thinking about the Clearvue design that fits on a Rigid shop vac, but the particular model wasn’t available in my local store. Local metal shop quoted $250 to make me a mini Pentz and the Clearvue with shop vac was going to run $300.

The filter picture in this project shows 30 minutes of routing MDF before I built the dust separator. Being it was a finer dust, it caused it to go directly to the filter and stick. After this build, all of the MDF goes into the pail and the filter is still clean after 5 months. The air in the work shop is quite noticeably cleaner.

Being limited to six pictures, I chose the most basic steps. There were no plans for this, it is quite simple after you read the Phil Thein website and read his forum. My build was only one day and cost less than $25. There is a picture section at Phil’s site that people have submitted of their builds. Essentially, a circular cyclone is created in the dust separator by the shop vac suction. the dust spins until it gets over the opening and falls to the bottom of the separator. Phil has the number of degrees and some other dimensions at his site.

I bought two plastic paint pails with lids from the blue store becauce of the flanges on the outside to stack them.

I then cut one of the pails and drilled a hole with forstner. To elongated it I with a dremel until the plumbing tube fit on an angle. The tube has to extend into the separator enough to go beyond the center.

A glue gun was used to attach the tube to the pail. I found later that pinholes were still in the joints and I had to use silicone caulk for a tight fit.

Then tracing the pail, I made the two baffles out of MDF. Then some plastic tubing to separate them and long bolts that went through the top of the pail. I used another circle of MDF on the top for strength.

From the electrical department I bought a round plastic box cover which I mounted center into the lid with the screws. Then using a larger forstner bit cut a hole to match the plastic tube. Again used the glue gun to mate the tube to box cover.

Final plumbing is to connect shop vac to tube pointing up from center and the tool to the tube pointing out the side.

After some use I found a small vacumn leak between the pails. So I went to the local hardware store and had an oring made of 3/8” rubber tubing. Also I am using three small bungee cords from the long bolts to the bottom of the lower pail for insurance. Actually once the shop vac is on you cannot separate the pails.

Hope this gives the idea and can help someone. Visit Phil’s site at;


20 comments so far

View cwdance1's profile


1163 posts in 4337 days

#1 posted 07-23-2009 10:51 PM

This project is on my to do this for this weekend. Glad to see its as simple as the web site says it is.
Great job.

View PurpLev's profile


8652 posts in 4727 days

#2 posted 07-23-2009 10:52 PM

looks great. this is one terrific upgrade!

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View DonDA's profile


193 posts in 4310 days

#3 posted 07-24-2009 01:02 AM

Love the idea- think I’ll try it.

-- Don, Saginaw Mi

View Bureaucrat's profile


18340 posts in 4730 days

#4 posted 07-24-2009 02:03 AM

This was very helpful. Thanks for posting the link.

-- Gary D.

View JeffStarr's profile


90 posts in 4414 days

#5 posted 07-24-2009 05:00 AM

Thanks for this post, very informative and useful.

-- "When was the last time you did something special for your gun?"

View a1Jim's profile


118162 posts in 4655 days

#6 posted 07-24-2009 05:21 AM

View degoose's profile


7281 posts in 4433 days

#7 posted 07-25-2009 12:49 PM

I have three shop vacs and they all clog up ,, I need one of these or three.
Thanks for the post to galvanise my thinking,.

-- Don't drink and use power tools @

View Sandy's profile


245 posts in 5003 days

#8 posted 07-25-2009 03:33 PM

I was originally going to build a separator as described by Phil Thien, but then I saw the recent projects relating to the duct work mod for making the cyclone. Then, when I saw your version of the Thien separator, I realized that your mod appears to simplify the alignment of the wood disks, as you are not trying to use the modified top described by Thien. As I have now collected all of the parts to do both, and as I have multiple (clogged) shop vacs, I may do both, but I have a question regarding your version. While I realize that there are Lumberjocks in Australia and other parts of the southern hemisphere where “cyclones” rotate counterclockwise, when viewed from above (due to coriolis force), in the northern hemisphere rotation is clockwise, so why do you have the intake pipe pointing in the direction to counter the normal cyclonic rotation? Doesn’t that slow the action?

View Occie gilliam's profile

Occie gilliam

505 posts in 4375 days

#9 posted 07-25-2009 03:39 PM

Hi Steve
thanks for posting this. I need to build one myself.

-- OC down in Costa Rica. come down and see me some time. I'll keep the light on for you [email protected]

View SteveMI's profile


1167 posts in 4373 days

#10 posted 07-25-2009 06:34 PM


I hadn’t really thought about the direction of the inlet tube during the build, but think that this device is an “artifical” forced cyclone with no relationship to the atmosphere. The cyclone reference is just that the dust is forced to rotate until it drops and the shop vac suction isn’t the preferred path.

On my Sears shop vac the inlet to the can has a very minimal horizontal bend inside and the filter is on the same level horizontal as the inlet. Any fine material picked up by the hose seems to go directly to the filter and clog it while the heavier go to the bottom.

Can’t defend the science, only know that this works awesome for me. I’m retired and the reference to coriolis force really took me back a number decades in school. If I remember right, water rotation down a drain in the opposite direction also. Always wondered what the affect is directly on the equator.


View SteveMI's profile


1167 posts in 4373 days

#11 posted 07-25-2009 06:38 PM

Just a tip, if you are building this at a larger scale to use a drum or garbage can, read Phil’s forum as there are some issues with the walls of the can collapsing. I chose these pails due to the ribbing and short distance that wasn’t supported.

View Sandy's profile


245 posts in 5003 days

#12 posted 07-25-2009 11:58 PM


First, coriolis force is not caused by the atmosphere, but by the rotation of the earth. The fact that coriolis force is often associated with the atmosphere is based on the fact that once one gets into the mid-latitudes (around 40 degrees north or south of the equator) the atmosphere is sufficiently affected by coriolis force that we get hurricanes and cyclones (also called “tornados” and “typhoons” which have a clickwise rotation, while the roation of “anticyclones” is counterclockwise). In the southern hemisphere the most notable issue is that when toilets are flushed, the water goes down in a counterclockwise rotation.

While you are correct that the suction of the vacuum provides the first order affect, my question really related to whether you had considered the issue, as the vacuum must overcome the coriolis force if the tube is inserted to cause counterclockwise rotation, whereas it would enhance the coriolois force if reversed. By way of example the next time you flush a toilet (in the northern hemisphere) you will note that the opening is directed to one side of the bowl whereby it acts in conjunction with the coriolis force, rather than against it.

In that you hadn’t really thought about the direction of the inlet tube during your build (and you’re in the northern hemisphere), my suggestion is that others point the tube in the other direction, as the “cyclone reference” really relates to the manner in which the separator works.

In answer to your question, directly (a fine line, indeed) at the equator there is no coriolis force, although on either side the force does exist.


View Karson's profile


35273 posts in 5479 days

#13 posted 07-26-2009 12:16 AM

An interesting solution to dust collection. Nice job.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia [email protected]

View Bullet's profile


150 posts in 4408 days

#14 posted 07-27-2009 06:05 PM

Hi All,
Here is a clarification on the Coriolis Effect from a proffessor at Penn State. It seems that the force is negligible on a small scale – so we don’t really need to worry about it for our dust separators. It’s an interesting read.

-- Anything is possible when you have no idea what you're talking about.

View jayjay's profile


639 posts in 4124 days

#15 posted 02-25-2010 04:18 AM

Thanks for sharing, That’s is great!

-- ~Jason~ , Albuquerque NM

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