# Making the Jerrjens Mini-Cyclone



## Don (Dec 18, 2006)

In one of my early blogs, I made reference to the dangers inherent in inhaling wood dust. Over the years, I've concluded that any small particulates that find their way into the lungs are a health hazard. We all know the risks to ones health from smoking, airbourne asbestos, coal dust, etc. And the claim is made by some that some species of wood are actually carcinogenic. Regardless of the scientific validity of these claims, any woodworker will attest to the fact that inhaled dust is not a good thing. Most of us will have experienced clogged nasal passages and even blood in our hankies when trying to clear the nostrils. This cannot be a good sign.

There are many steps a prudent woodworker will undertake to prevent dust inhalation. To name a few, there are various dust masks from the simple, inexpensive throw-away paper filters to the positive-pressure air respirators; there are central ceiling mounted air filters, and there are Dust Control Systems that can be simple or very complex. I have posted a link to Bill Pentz' site where he discusses dust extraction systems with a particular emphasis on cyclone extractors. If you spend any regular amount of time in an enclosed workshop environment, it would pay you to spend some time reading the research Bill has done on the subject. He is the woodworker's cyclone guru.

Regardless how good your dust extraction may be, there is still ambient dust that escapes these and settles on the various surfaces in the shop. (As an aside, I frequently don my air respirator and turn on my air filter and start blowing off all of the surfaces in my shop with compressed air. Some of it escapes outside my open door, and some gets cycled through the shop air filter where it is trapped. Unfortunately, some of it resettles back on on the same surfaces.)

This is where a good shop vac comes in. For clarity, I am referring to a portable vacuum cleaner that we use around the shop to pick up wood dust and wood chips; the stuff that gets away from the ducted central DC System. Unfortunately, most small shop vac's suffer from dust clogging, and may eventually burn out. (Think of the dust bag as akin to you lungs.) A good mate of mine, Peter Jurrjens, who has a local reputation amongst woodworkers for being very innovative, borrowed the concept of the cyclone from central DC systems and adapted this to the shop vacuum. It's known locally as the *Jurrjens Mini-Cyclone. *










In essence, he designed a pre-filter to remove the majority of dust and chips before they reached the dust filter bag of the shop vacuum. The benefits are many; a cleaner shop, less frequent bag changes due to the larger storage capacity of the cyclone, no loss of vacuum power due to clogging, and protection of vacuum motor preventing burn-out. This is a relatively easy modification that will take only a few hours to do, and cost probably less that $25.00.










The cyclone consists of a two-stage unit. The top stage is made up from plastic paint buckets and a large plastic funnel to form the cyclone section, the lower section is a metal paint bucket that serves as the waste/dust collector. A look at the schematic will help you visualize this. The hose fittings are common plastic plumbing fittings. Two hoses fit into the top lid. One runs to the shop vac, and the other is used to pick up the dust and waste around the shop. The action of the air circulating around the upper unit is caused by the funnel shape of the top section. When dust and chips are sucked up into the mini-cyclone, the heavier material falls immediately to the lower container. The cyclone action of the air-flow throws slightly lighter particles to the outside walls of the cyclone by centrifugal force. When this lighter material hits the walls, it spirals down the cyclone walls and through to the lower container. Only the very lightest of material finds it way up through the vacuum hose into the vacuum bag. In my experience, you can fill the larger cyclone container two or three times before needing to change the vacuum bag.










I am hoping that the schematic shown here is sufficient to inspire LumberJocks to make their own mini-vac systems. You will never regret taking the time to make this fantastic little shop aid. If you have specific questions regarding this, I will either answer them myself, or have the designer of the mini-vac answer them for you.










I am not bothering changing the metric measurements to Imperial. If you can't relate to metric, then do your own conversion. [1" = 25.4mm]


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## MsDebbieP (Jan 4, 2007)

1. Here's a conversion chart that might help the non-metric people 
2. I admit it - I skipped this one. Why? Well, I've found that the technical information posted on blogs etc here on LJ is "way over my head" generally so I just skip it for now, knowing that when I'm ready I know where to find it. And so I skipped passed this one, not knowing what it was really about. (A lesson for me-read all the messages on LJ.)
3. This is very interesting and yes, very important. I hate the thought of all those tiny particles of wood (and who knows what else) going into my lungs. I'll be printing this one off! Thank you for taking the time to share this with us


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## scottb (Jul 21, 2006)

Can't believe I missed this one… you may have just saved me a bunch of cash over the one you can buy and mount to your own 5 gal bucket, for considerably more $...

and to think I was just at the Big Box store this afternoon, picking up some plumbing fittings to fix a corroded pipe under the kitchen sink. I could have grabbed these when I was there.


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## Obi (Oct 19, 2006)

Don't feel bad, Don, I read it and instantly tried to figure out how to make one. I woke up thinking about a Cyclone Dust Collector, so it did have an impact. I just didnt want to look stupid but I don't really care now, so here goes:
1) what hooks up to where? And how can i turn my current shop vac into one? the price is good, and can I convert my regular dust collection system into one?


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## Dusty (Jan 8, 2007)

I hadn't seen the post Don, It was one of those days, I found it very informative and useful. thank you.

P.s 
As a side note to your comment "its getting so busy" boy isn't that the truth. any ideas?
There is so much to read-and I find very useful. I just have to find a way to take it all in.


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## Chipncut (Aug 18, 2006)

I seldom use my shopvac as an attachment for dust collection because most of my equipment is attached to my dust collector. Another thing, my shopvac is so noisy.

Thanks Don, it did made me think about making something like this with larger fittings for my dust collector. 
I have a question though, does the cyclone dampen some of the noise?

*Comment:* One thing I never do is use an air hose for cleanup, doing so your just putting more dust into the air, that's why I bought a shopvac.


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## scottb (Jul 21, 2006)

Question about the lenght of the hoses…. should I have this mini-cyclone near the shopvac and make them both mobile, (Dick - I've seen plans where you can make a plywood box, lined with carpet or insulation as a sound buffer - just leave a hole for the air exchange) or can I stash them under a workbench and just get a longer hose?... or perhaps my question is, what is the point where this will loose its efficiency with lengthening the hoses?


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## Don (Dec 18, 2006)

*Quote Obi:* "...what hooks up to where? And how can i turn my current shop vac into one?"

Obi, re-reading my post, I now realizes that I used a term that may have given the wrong impression. I referred to a "shop vac". More specifically, I am referring to any small vacuum cleaner such as a domestic house vacuum cleaner. Of course, it could also be what the big box companies call a shop vac. The main purpose of the Mini-cyclone is to remove as much of the sawdust and larger wood particles before they get to the vacuum's filter. The power of the vacuum cleaner decreases in inverse proportion to the amount of debris that clogs the filter device of the vacuum cleaner. So the mini-cyclone serves as a pre-vacuum separator removing most of this debris.

Now, the plumbing is quite simple.

The hose from the vacuum cleaner is attached to the the through-lid fitting that goes to the long pipe that runs down through the center of the cyclone unit (one of the pictures shows a ruler held next to this pipe - it is about 11 long. It extends down to and level with the top of the plastic funnel that forms the cyclone.

The cyclone and the lower holding tank must be constructed in such a manner that the only air that enters the two stage canister is through the second pipe with a right angle. This pipe is connected to the hose that is used for picking up the dust, dirt and debris. If any air is drawn into the canisters through an unsealed opening, it reduces the effectiveness of the cyclone.

*Quote Dick:* "I have a question though, does the cyclone dampen some of the noise?"

No, the cyclone has no affect on noise. It doesn't dampen or increase it. Peter Jurrjens uses ordinary domestic vacuum cleaners installed in sound-proof housings around his shop. (See Scott's comment on this.) I think he has at least 3 of these. Remember, the mini-cyclone/vacuum system is only used for cleanup. It is not left running like the DC unit. (I have installed my DC unit in a separate space under my house where it cannot be heard in the shop.)

And yes, Dick, the mini-cyclone takes the same principal of a cyclone separator used in line with a DC unit. I also have one of these. But as I stated in my article, the Mini-Cyclone is used with the shop vac when cleaning up around the shop the stuff that escapes from your central DC system.

*Quote Dick*: "Comment: One thing I never do is use an air hose for cleanup, doing so your just putting more dust into the air, that's why I bought a shopvac."

Dick, you are right. Blowing the dust with the air hose does put the dust into the air. That's why I turn on the shop air-filter unit to catch some of this airborne dust. But I also wear my Triton Air Respirator when blowing the dust out of the many awkward hard-to-reach places in my shop. (I plan to write a review on this under a separate blog.)

*Quote Scott:* "Question about the length of the hoses…"

Scott, the hose on my unit between the vac and the mini-cyclone is 2.5 meters. The actual pickup hose is 1.5 meters. There is no apparent loss of power, but I guess this might occur if the hose was exceptionally long.

Your suggestion about the mini-cyclone being on wheels to make it portable is a good one. I've seen woodworking mates put both the shop vac and the mini-cyclone on a small cart to make the whole affair portable.


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## scottb (Jul 21, 2006)

Thanks Don… I was planning to do just that (make a cart - with some sort of silencer) but would have made a built in unit under a bench if a longer hose would have worked. Didn't think so, but was hoping. Most of my tools aren't that scattered, but a 4-5 foot hose won't cut it.


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## Don (Dec 18, 2006)

Of course, Scott my setup has 4 meters = 13', and I've had as much as 18' all up with absolutely no deterioration is vacuum that I notice.


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## Karson (May 9, 2006)

Just a little bit of different information.

I've bought Hepa filters for my shop-vacs. A Ridgid and a Lowes brand. They are different size filters but I don't have any noticable dust come out of the back. I've used the Lowes one, attached to a drywall sanding attachment and It seems to stop all of the dust from getting through. They are suppose to be rated at a low Micron range.

The Ridgid vac I've had full where the hose got full and it was still sucking as if nothing was in the vac. Thats why I kept sweeping up. It didn't seem full. I'm quite happy with those filters. The dust just knocks off when you tap the filter against the trash bin. If you hit them with an air gun I've noticed some pealing of the filter material.


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## Don (Dec 18, 2006)

Karson, it depends on the configuration of the filtering device. Some lose efficiency when the filter clogs, others simply pass the dust right through and the whole process is counter-productive. Still others use a kind of mini-cyclone built within the vacuum.

__Peter Jurrjens has been monitoring the responses here and sent me the following.

Don,

I've been reading the postings at Lumberjocks. In regard to
Scott's comments of length of hose I think the hose can
be much longer.

Firstly if he puts the mini cyclone next to the vac in
a permanent situation he can shorten the connecting
hose and then use a longer hose for pickup.

The unit we took photos of has a hose that can reach
anywhere in the main part of the workshop and I have
regularly used an extension hose to reach up into the
far reaches of the back part of the workshop which
would be at least 8 meters.

When I use it for cleaning I have the reducing hand
wand attached to the hose which helps to concentrate
suction , this normally comes with the vac.

Another point that you haven't mentioned is that with
the appropriate adapter the mini cyclone hose can be
attached to hand held tools like a sander or router or
as I intend to do attached to the CSM Saw or to the
overhead guard on the TS.

With the appropriate wiring the vac can be controlled
from a central location especially if the vac is built
into a soundproofing box.


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## Karson (May 9, 2006)

Don: I think what I was trying to relate was that the hepa filter didn't seem to clog at all and it had full vacuum use even when the vac was full. Here is a web site that talks about HEPA Filters that filter down to 0.3 Micron


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## Obi (Oct 19, 2006)

O.K. All I want is to see a picture of the entire set-up.


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## Don (Dec 18, 2006)

Thanks for this, Karson. Very interesting. Imagine combining a HEPA filter with the mini-cyclone - I think you would have the perfect setup. The first stage being the cyclone would filter out all of the larger particles and the HEPA filter would capture all of the microscopic particles.

*Quote Obi:* "All I want is to see a picture of the entire set-up."

Obi, this one shows a modified Triton Dust Bucket. Whilst it differs in detail from the pictured above, it is essentially the same modification. The upper chamber is the Triton bucket (substitute any similarly sized bucket), and the lower chamber is the paint tin (usually available free from a paint supplier) which serves as the dust container.

You can clearly see the funnel, and the two through top-pipes. The one with the elbow is attached to the pickup hose and the other one with the long pipe extending down to the top of the funnel is connected to the vacuum hose.

One other point; the lid through which the pipes feed only needs to be tight. It everything is sealed, the vacuum creates a tight fit making it next to impossible to remove the lid when the vacuum is on. The lower connection between the two sections is sealed with the lower lid clamp.


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## Obi (Oct 19, 2006)

Thanks Don, now I can see what plugs into where and with the detailed information, I can probably figure out how to put all this information together.

I thought the angled piece went to the vacuume and the strait one went to the attachments… that way the stuff that was sucked up would be lower than the one that went to the vacuum and the filter.

Does hooking it up backwards change the operation, or has anybody else tried that?


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## Don (Dec 18, 2006)

It simply won't work if hooked up backwards (even in OZ). The long pipe creates the vortex in the funnel.


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## oscorner (Aug 7, 2006)

http://www.woodcraft.com/articles.aspx?articleid=408: Check this site out! I built one of these and it works like a charm. The only thing that gets to my dust collector is dust, now. Before building this, my 4" flexible hose would plug up when using my planer. Emptying the can is a lot easier than removing the bag on the collector, too.


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## Don (Dec 18, 2006)

Mark, this is exactly the same idea only on a larger scale. And Obi, this will help you to visualize the setup for the mini-vac. I also have one of these on my DC System; the head of the pre-separator comes from Lee Valley.


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## Obi (Oct 19, 2006)

That's what I was looking for. I just love what pictures do to a tired mind. Trash can, and some 4" PVC plumbing.

Thanks for everyone's help


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## Don (Dec 18, 2006)

Perhaps I'm reading too much between the lines. But there seems to be a slight misunderstanding about the Jerrjins Mini-Cyclone unit.

*It is not a replacement for a central DC* [*D*ust *C*ollection] *System*. It doesn't do the same job, nor is it intended to be the primary dust extraction device in the shop.

It's primary purpose is twofold.

1. To clean up dust, woodchips, and miscellaneous debris around the shop, i.e. shavings from carving , using a hand plane, drilling, etc.

2. It is ideal for use with portable devices that have a dust port, like a sander, electric hand plane, etc.

The central DC unit removes dust and debris from their source of origin by directionally moving large volumes of air, i.e. from the planner or table saw to the dust collection unit. It is essential that there be an opening into a planner of TS that is as large as the opening where the air departs from these machines. This is usually not a problem because both of these example have openings as large or larger than the size of the exit ducting.

This is why central DC systems do not work well when you restrict the hose size to a diameter smaller that the main hose. If you have 4" or 6" ducting, a reduction to 2" greatly impedes the flow of air thus reducing the effectiveness of the DC's performance.

A general rule applies to both systems. *Maintain the same diameter ducting/hose throughout the system. * With vacuum units, this is normally 2". When it comes to central DC systems, Bill Pentz highly recommends the use of 6" rather than the commonly used 4" ducting.

On the other hand, a shop vacuum works by sucking rather than blowing the air. The vacuum created by the vac unit sucks air at a high velocity. To maintain the effectiveness of the vacuum, it is essential to keep the "ducting" at the same diameter of the hose going into the vacuum unit. That's why the hose going into the mini-cyclone is the same size as the hose going out. If you used a larger diameter pickup hose it would lose its vacuum and wouldn't pick up the debris.

So, it is erroneous to make a comparison between the two systems (central DC & Min-Cyclone/Vac). They don't do the same job, but serve entirely different function. If this subject confuses you, and/or interests you, spend time reading Bill Pentz very learned treatise on this subject.


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## oscorner (Aug 7, 2006)

Don, I didn't mean to cause any confusion or to compare the seperator I made to yours. You just gave me a venue to share this plan with the LumberJocks. Since they both work on the same principle, the design causes a swirling of the air in the chamber allowing the larger particles to fall out of the air stream before it reaches the vacuum, I thought it would help those looking to build a larger version of your mini cyclone.


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## Don (Dec 18, 2006)

Actually, Mark, your comment and picture was very helpful as it clearly showed the configuration of a cyclone.

As I said, I was probably reading too much between the lines. Because the cyclone separator works with both a central DC system and a shop vac is easy to conclude that the mini version can do the job of the DC, which it can't. It's a matter of scale. The former is designed to move a large volume of air at relatively slow speed, whilst the latter draws a restricted volume of air at high speed. The former uses fixed ducting to stationery machines, whilst the latter uses flexible movable ducting to portable machines and to all shop surfaces.

I'm sure that there is no longer any room for confusion between these two complimentary systems. *Enough said by me unless there are specific questions. *


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## Obi (Oct 19, 2006)

I'm glad you helped clear up several things for me Don.
1) It won't work at all if you hook it up backwards.
2) You'll lose power if you try to interchange the hose sizes.

My main question (which you answered) was can I hook that up to my shopvac. My main DC has 4" hose but I want to hook up something over the table saw to get the dust that flies right up in my face. I have a respirator, but sometime fail to use it because I'm just making two or three cuts, but habit makes me turn on the dust collection every time i turn on the saw.


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## Karson (May 9, 2006)

I found the web site that is from the MFG of the filter that I use on my shop vac. They state that the filter traps 99.7% of 0.3 Micron dust which is the rating required to be classified as HEPA .

They have a video that shows the filter in action using equilivant DryWall dust.

Its here


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## Steelwinky (Jan 14, 2007)

Any suggestions on making the actual funnel portion? Do they sell funnels that large, the same size as the inside dimensions of the bucket?


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## Don (Dec 18, 2006)

*Quote Steelwinky:* "Any suggestions on making the actual funnel portion? Do they sell funnels that large, the same size as the inside dimensions of the bucket?"

Yes. You may have to do a little searching, but they are definitely out there. I purchased mine at a big box hardware store, Bunnings Home Hardware, equivalent to your Home Depot.


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