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Jul 28, 2012, 08:22 AM
Proud to eat Kraut ;-)
Julez's Avatar
Thread OP

Dust Captain cyclone separator and DIY water prefilter for workshop dust collection

Hi Guys!

I would like to show you the system I built to cope with the dust in my workshop.

Attention! This setup has seen various improvements and refinements during the years, so be sure to read this thread completely for the latest version!

Here's the product demonstration video of the Dust Captain:

Dust Captain Zyklon Abscheider Demonstration (2 min 45 sec)

Here is a video of my setup. It is a little outdated, as I recently added the Dust Captain cyclone separator not shown in the video. I also cleaned up the connections between the several filter stages.

My workshop vacuum cleaner filter system (9 min 58 sec)

Some time ago, I was annoyed about all the dust in my workshop, and decided to get a vacuum cleaner. I knew, however, that ordinary ones get clogged very quickly by fine dust, and that most filters are not fine enough for the very fine dust, which would be dangerous when grinding glass fibres or else.

I decided to make a pre-filter. I flirted a bit with the idea of a cyclone filter, but learned that these do not get the fine dust as well. Boy, was I wrong! But more on this later.

The first stage is the "Dust Captain" cyclone separator.
It has the advantage that it never clogs and that it can, depending on the bucket capacity, remove huge amounts of dust from the air. This is why cyclone separators are very popular among woodworkers and carpenters, professionals and hobbyists alike. As I do not tend to produce massive amounts of dust, a 20l cooking pot was enough for me. Getting a hole in the lid was lots of work, as stainless steel is difficult to machine. My DIY grinding disc got the job done though. I applied a bead of goop to seal everything while bolting the Dust Captain down. As it is most important to have the bucket totally airtight to be able to remove fine dust, I also put a stip of 10x3mm adhesive cellular rubber around the edge of the lid. The rest of the installation was a breeze. The ports have an outer diameter of about 56mm, and the inner diameter is precisely 50mm. 2 short pieces of 50mm plastic tube are included, which fit snugly into the ports with a little pushing. Now I pushed plastic plumbing adaptors (50mm to 40mm) on the 50mm tubes sticking in the ports. Like this, I can conveniently connect a 40mm vacuum hose or additional 40mm plumbing for the air. It's a very clean solution without messing around with adhesive table, leaks or loose connections. Everything appears as it was made to fit together.
A first test showed amazing results. As expected, heavier dust as metal chips or trimmed-off cable pieces were separated nicely. But when I vacuumed the floor around my workbench, I also found very fine and fluffy dust flakes in the bucket. This really surprized me, as I previously thought that cyclone separators mainly filter rough dust. This one seems to be really well-designed.

As I am paranoid about very fine glass fibre dust, the second stage is a "water-filter" where the air is washed before finally reaching the vacuum cleaner.
So, a water filter shall be built!

I quickly found a perfect base model at Amazon, the "Aqua Jumbo":

They are made of tough, thick plastic, and have an awesome price. On the inside, the tube nozzles connect perfectly to the 40mm PET drainage tubes I got from the hardware store. They also come with a kind of telescopic tube, consisting of 3 pieces of slightly conical tubes. When cut into little pieces, they make great adaptors for the whole system if you need them.

As I said, I used 40mm PET pipes to lead the air where I want it to go.
I just improved my filter system a little.
Previously, I aimed at blowing the dust out of a nozzle below the water surface. This created lots of bubbles, turbulence and spray. Consequently, I had to add a water separator after the water filter to remove the water spray from the exhaust air.
Now, I tried a different approach. The air travels through a pipe in the water, and a gap allows water to enter the airflow. At the end, I added a large pipe to slow down the airflow and allow the spray to settle.
It works really well. The flow is now much more homogenous and predictable, and there is hardly any water spray at the exhaust.
The water filter guts are 40mm, 50mm, and 75mm drain pipes.
The concept is explained in the video.

Instead of pushing adaptors into the ports of the Aquajumbo lid, and thus constricting airflow, I increased their outside diameter a little using fibre tape. This way, I can push on 40mm PET pipes with seals inside, to which other 40mm Pipes of my setup can be connected convenintly.

I am very satisfied now!
This system takes all kind of dirt, raw metal chips from the drill press to very fine dust from the grinding machine. (This dust is now collected by the Dust Captain.) The typical dusty smell some vacuum cleaners produce is totally absent, one only has the faint smell of moist air, like after rain. After some time I checked the filter back in the vacuum cleaner at the end of the system, and there was zero stuff insinde. Not the slightest bit. I guess it will run forever on only one filter bag.

The downside in the lack of mobility, but as I only produce dust on a single table in my workshop, I can live with it.
When the water gets too dirty, I pour the bucket into the nearest toilet, and fill it up 25% with fresh water. This is not more hassle than changing a filter bag.
As I do not grind that much wood, I do not now how wet sawdust will react over the time. Maybe one will have to empty the bucket once a week then.

Edit: Update about the tubing here:


Last edited by Julez; Jun 13, 2021 at 03:53 PM. Reason: Update
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Jul 28, 2012, 10:39 AM
B for Bruce
BMatthews's Avatar
An EXCELLENT project done very nicely and well presented. I've copied and saved your pictures and text for a bit later when it's time to install a dust collector.

It'll be interesting to see if someone tries it for balsa wood dust and how well it works out.

I may also look at trying out a bigger version of your system for a full on wood working collector. The bags and filters found on those systems tend to clog or pass the fines as well. A water bath pre-filter from the sander and other machines that produce the very fine dust might just be the ticket.

With a little more work I could see a small stand being a handy thing so the canisters sit one over top of each other. It could then be equipped with a small set of wheels and a handle so it can wheel around to whereever it's needed.

It looks like I'll need to find a different set of cannisters. I can't seem to find any reference or supplier for these pre cannisters on our local Amazon or through ebay.

The other thing that I may try is to plumb up an inexpensive wet/dry shop vac to extend the inlet down into some water in the base as the filter and see if I can shield most or all of the water from misting up through the outlet.
Last edited by BMatthews; Jul 28, 2012 at 10:45 AM.
Jul 28, 2012, 11:14 AM
Proud to eat Kraut ;-)
Julez's Avatar
Thread OP
Hi, thanks for your friendly reply.

With a little more work I could see a small stand being a handy thing so the canisters sit one over top of each other. It could then be equipped with a small set of wheels and a handle so it can wheel around to whereever it's needed.
Now that the second stage of the filter is almost superflous, one could also remove all the filter bags from the vaccum cleaner (I have a wet/dry version), and let it catch the trace amount of water. Then one would only have the water filter and the vacuum cleaner, and they could bee mounted on a creeper dolly together.

Here is an example with a cyclone separator:

For large amounts of dirt or lots of sawdust like in a wood workshop, a cyclone separator as in the ling above as a first stage would be best. This would filter out the biggest share of the dust, leaving only the fine dust for the water filter.

In the picture I stole from this thread is the ingenious idea of a fellow from Germany.

Here is also a nice thread about DIY cyclone separators:
Last edited by Julez; Jul 29, 2012 at 04:13 AM.
Jul 28, 2012, 07:54 PM
B for Bruce
BMatthews's Avatar
Yes, between a cyclone separator to get the lumpy stuff and the water filter for the fines you may not need an actual bag just as you say. I'm liking this whole schtick as most of the felt bags used on bigger dust collectors for home shops still do not remove the very finest wood dust. And since I'd LIKE to re-circulate the air back into the shop instead of sending it outside in winter this is looking like a pretty trick setup.
Jun 30, 2013, 11:46 AM
Proud to eat Kraut ;-)
Julez's Avatar
Thread OP
I have put the water filter to good use during the last year, and it worked flawlessly!
I do not know how I got along before having it...
Jun 30, 2013, 06:37 PM
Play that funky music right
kenh3497's Avatar
Five gallon buckets that have a lid on them could be used. I don't know if Home Depot or Lows have the lids. I know they have the buckets.


Just a thought.... Many restaurant foods come in five gallon buckets. You know where to take it from here.
Jul 01, 2013, 11:05 AM
Proud to eat Kraut ;-)
Julez's Avatar
Thread OP
Yeah, basically any container large enough can be used, if one manages to get the pipes through the lid without too many leaks.
Jul 02, 2013, 06:04 PM
B for Bruce
BMatthews's Avatar
Thanks much for the update Julez. I've just about got to the end of my retirement shop renovations and your updating this thread has me interested all over again as the dust collection setup is next.
Mar 22, 2014, 10:23 AM
Proud to eat Kraut ;-)
Julez's Avatar
Thread OP
I just edited the OP with some improvements I installed recently.
Mar 22, 2014, 09:58 PM
Neophyte hacker
portablevcb's Avatar
Similar have been around for a while, at least 30 years.

The home made versions work well if you don't have to move them much. A key is to make the underwater section produce finer bubbles. The rest is just to make it easy to clean out.

Another method is to use wet pads similar to an evaporative cooler.

Mar 24, 2014, 12:37 PM
Proud to eat Kraut ;-)
Julez's Avatar
Thread OP
Yes, my parents use a rainbow for quite a long time!
But these should not rest longer times with the water tank filled, as motor parts can corrode that way. At least this was the situation some time ago.
Mar 24, 2014, 02:58 PM
An itch?. Scratch build.
eflightray's Avatar
Vacuum cleaners ?, water filters ?, heck, you're not a builder if you can still see your feet in the dust and balsa shaving covered floor.

Mar 29, 2014, 11:38 AM
Registered User
Just wondering IF I were to put a gallon or 2 of water into my Shop Vac (most all models are 'Wet 'n Dry' units)
IF... it might do similar dust removal duty ?
Likely not as efficiently ....but Dead simple to fabricate.
Mar 29, 2014, 02:22 PM
B for Bruce
BMatthews's Avatar
Originally Posted by Bare
Just wondering IF I were to put a gallon or 2 of water into my Shop Vac (most all models are 'Wet 'n Dry' units)
IF... it might do similar dust removal duty ?
Likely not as efficiently ....but Dead simple to fabricate.
Since the air comes in at the top and would swirl around somewhat SOME would go into the water but not a whole lot. Most would still be trapped by the required filter you'd need to use.

On the other hand it would not be hard to modify a shop vac to have the inlet go down and into the water so that the dust and chunks exit the end and drive down into the water......

In fact I just did a search and one of the suggestions was for "vacuum cleaner with water filter". When I went to the images for this search the very first one is how a shop vac could be easily modified into a water filter style.

The same setup would work just as well for a pre-filter canister.

Most shop vacs have quite a lot of room from the base to the filter. For those a separate baffle that blocks the water and has spider arms out to the sides to let the air get past would work much like the heavy base.

I'm thinking I might just need to have a go at converting one of my shop vacs. I often have to suck up fine dust such as dry wall sanding. That sort of thing plugs up the $8 bags in a blink. A cheap to refill water filter setup would be just the thing.
Mar 29, 2014, 04:06 PM
AndyKunz's Avatar
You need a wetting agent in the water to make it really work, otherwise the dust just passes through the water. Check out the Rainbow vacuum folks for them.


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