Click HERE For Special Deal On LEESON 5HP Cyclone Motors

Growing concerns over health issues plus the constant layer of dust over everything in my shop led me to the project of building a DIY cyclone. This is a detailed account of the construction as well as some info that I think will be useful to those starting from scratch. I hope you find the information contained in this page useful. 

CYCLONE (Sheet Metal Work):

TIP: Do NOT use silicone as a sealant for you galvanized metal parts! Silicone will not stick to galvanized long term and will leave you with leaks! Buy a tube of "DUCT SEALANT" from an HVAC distributor. It's an reddish brown goop that sticks like anything and is made for sealing galvanized and other HVAC metals. It cleans up with Acetone. Don't use it on anything you expect would ever need to come apart as it is not easy to get apart once cured.

TIP: If you want to build a cyclone but the metal work has you thinking twice check out my links page! A kit form of Bill Pentz' highly efficient cyclone is under development for sale at a very reasonable cost. This kit might be just the ticket for many of you that have hesitated to step into a cyclone project for lack of skills in metal working!

The metal is 24ga galvanized sheet metal which cost around $50.

I was lucky enough to find a sheet metal guy to fabricate it all for another $50. It's a basic WOOD magazine unit but with a neutral vane added which reduces the static pressure overhead by at least a full inch H2O or better! 

In the second pic I show the WOOD plan framed MDF enclosure which I later decided to scrap. If you look at later finished pic's of my cyclone you will note only 2 MDF rings around the union of the cone and cylinder. This is all that's left of the standard WOOD mounting system! These 2 discs simply hold the 2 tin halves together with a bunch of duct sealant in between for a good seal. The first time I picked up the WOOD box I knew it had to go... MAN it was heavy, far too much for a 1 man installation, especially if I was going to need to pull it down a few times during testing!

I ended up mounting a couple extra wooden discs to the bottom of the blower housing (I made the cylinder 1.5" taller than the plan so my finished height inside was the same as the original with the extra disks inside). The cylinder slides snugly up over these and a few self tapping screws are all that's needed to hold the cone and cylinder in place. Without all that MDF the cone and cylinder are quite light and it's no problem to suspend them off the blower (which gets securely mounted to the ceiling).  Mounting it this way allows easier access should I ever need to disassemble the cyclone. A bead of removable caulking (Bulldog Draftstop) around the blower to cylinder seam helps seal any small leaks there and is still easily removable.

BLOWER:

The fan is from Cincinnati Fan, 14" diameter x 3.25" wide.

Cincinnati Fan PB 14"x3.25" radial blower wheel Spec's.

The motor is a LEESON 5HP single phase with a 'C' face for direct mounting.

The housing is shop made from 3/4" baltic birch ply (13 plys) and a 6" wide, 18ga strip of sheet metal that I had sheared and rolled to the basic shape to fit by hand.

All held together by 15, 3/8"x8" carriage bolts.

I formed the spiral in the plywood with a router, 1/8" bit, template and guide. To make the template I drew the spiral in AutoCAD and plotted it out full scale as I am lucky enough to have a plotter big enough to plot it full scale. 

Click Here -> to see the template drawing.

If you are not able to draw it in CAD there is still and easy way to make this spiral using some reinforced tape and a round can which can be found on Bill Pentz website.

Testing the blower out revealed that I seem to have been able to duplicate almost exactly the results that are shown on the Cincinnati's Fan curve for their factory made blower! With the cyclone off it draws 25A+, way over my 5HP  motor's rated full load amps of 20.8A. With the cyclone attached and neutral vane installed it draws just over 20A... near perfect for a cyclone as the blower will never need to run without the cyclone attached.

At 5HP I am moving about 1700CFM at about 3" H2O which is dead on the factory curve. If my blower follows the curve I should be able to reach my goal of 800CFM at around 12" SP.

This all translates into one powerful shop built cyclone :)

NOISE:

Noise was another worry. At first with the blower clamped to the bench and fired up one thing became crystal clear... this thing was LOUD!!!

Now that the ducting is all assembled and the filter is attached it has made a significant improvement in the noise level. So much so that I can talk over it but not so much that  ear protection isn't a very good idea. The most noticeable sound is a medium to high pitched whine. This may be due to the fact that the fan is quite close to the outlet cutoff and or because I have straight fan blades instead of backwards curved ones.  All in all it's quite acceptable. 

At a later date I will add some insulating pipe wrap to the outlet pipe going to the filter and either insulate or spray on some automotive type stone guard on the blower's metal strip to further quiet things down. A further step would be to insulate the cylinder and cone as well and should make for a downright quiet unit. 

ALTERNATE FAN SOURCE:

I have learned that JET sells a replacement 14" fan for their DC-1900 for about $70 US. This might be a cheaper alternative than the Cincinnati fan I used at $175 US approx. I believe the performance is a bit less than my fan but still should be ample for this type of cyclone & duct layout. Thanks to Bill Pentz for this tip.

Ducting - Where do I start???

The discussion of what to use in ducting seems to be an ongoing debate with as many different opinions as there are questions. There are a few common questions that you should know about before starting in on your ducting project.

1) Steel or plastic... which should I use?

This largely depends on your budget. There are 2 types of commonly used steel pipe. One (and undoubtedly the best) is spiral air ducting with the special connectors that go with it. This material is specifically designed for air handling and dust collection and as such is the best option. The drawback is it can be very expensive. Another very common solution is to use standard HVAC pipe or "Snaplok" and the normal home center array of elbows & fittings. While this is economical and readily available it is far from an ideal material for your DC system. The problems are really to do with the fittings and not the pipe itself. HVAC fittings are VERY poorly assembled with many ridges, swivel joints and interlocking tabs that protrude inside. All of these will cause resistance to the air flow and should be dealt with before assembly. A typical 'Y' in HVAC has dozens of little tabs sticking up inside that would need to be hammered down & soldered to get a reasonable smooth internal surface. To me this was just too much of a pain to be bothered with. HVAC pipe also has a seam all the way down that should be taped or sealed. There is also a crimped end on each piece of pipe that while not a huge problem will cause some added pressure losses in the system as the internal diameter decreases a bit at every joint, and there a lots of joints as the typical pipe length is 3' with some available in 5' lengths.

PVC S&D Pipe...

The other choice which you are likely to have heard of but never been able to locate is thin wall PVC. It will be readily available in 4" size at most box stores but VERY scarce in the required 6" size. You will need to find a big wholesaler of plumbing parts to find it. Look around and ask for "NON-perforated", PVC sewer & drain pipe, sometimes called BDS or S&D pipe (A manufacturer is IPEX if that helps them source it). It's white in colour, thin wall (around 1/8") and comes in 10' lengths. Do NOT let them talk you into schedule 40 PVC as it will cost you a fortune and is just too heavy for your needs. PVC has some nice advantages. It comes in 10' lengths, it is seamless, it's fittings make a nice smooth finish inside and if you don't glue it (not necessary) you can easily disassemble it later if need be. On the down side, there is also a healthy static shock that can zap you when using PVC so be aware. 

2)    Grounding

You can not ground PVC as you would metal pipe. A solution for this can be found HERE that involves using 2 strips of aluminum tape applied one inside and one directly outside of the pipe (like a sandwich). You then drill through the outer tape, pipe and internal tape strip and install a ground lug (carriage bolt etc) which gets grounded from the outside. I have not tried this personally as my system was already totally completed when I heard of it but I am told it does work.

The static shocks are more annoying if you touch the pipe than anything. In the past there was much talk and fear of dust explosion due to static discharge. Dr Rod Cole published an article entitled "PVC Pipe Dangers Debunked" in Fine Woodworking #153. Dr Cole says that "it is very close to impossible" regarding the possibility of ignition of dust in a 4" PVC pipe. He goes on to say that "dust collectors with 3HP or less pose little danger". The NFPA puts no regulations on dust collection systems of 1500CFM or less according to Dr. Cole's article. Larger ducts do pose greater risk of sparks however there still does not seem to be much concern with home systems under 1500CFM and 3HP. Since our ducts are typically restricted in maximum CFM by cyclones, fittings and dust hood overhead to something closer to 800CFM even the larger blowers like mine do not seem to fall into the "over 1500CFM" category. His article also mentions to the effect that there is in fact a greater risk of sparks in the typical DC bag than in a 4" duct.

2)    What SIZE pipe should I buy?

This is another hot topic of discussion. You will hear many opinions ranging from 4", 6", "whatever your DC inlet is" to "start big and reduce the size as you get further from the DC" etc... Many of these suggestions have there merits depending on the end goal of the system and on what type of system they are being installed. 

The old standard for DC was 400CFM which will pick up the sawdust and planer shavings. It is not sufficient to collect the truly harmful dust on your larger machines, for that you should shoot for 800CFM, DOUBLE the old rule of thumb! With the old DC mentality 4" pipe was fine. When you try to pull 800CFM however, it will become quickly obvious that 4" is just too small given our limited blower capacity on your typical hobbyist DC.

The key to moving more air through a small pipe is STATIC PRESSURE (or suction). Here's a chart (thanks to Bill Pentz) that show the approximate capacity of hobby type blowers based on fan size and HP. BLOWER CHART

Take an 11" fan as an example from the chart. At 5" SP the fan will pull 760CFM. At 7" it is down to 481CFM and is now pulling an unacceptable volume of air to do the job we need done.

Plugging some numbers into Bill's static calc shows that a typical 20' run of 4" with two 90's one 'Y' and 3' of flex requires 12.25" static pressure to move 800CFM. Obviously there's no way our little blower will deliver 800CFM under that load (it needs less than 5" to show us 800CFM). If we step this up to 6" pipe our total SP becomes only 1.8"!! Now our little 11" fan can happily pull 800CFM and more! I think you can see the importance of using larger duct sizes:)

Another consideration aside from the CFM is duct velocity. Your blower must be capable of moving the 800CFM in your ducts to keep the speed of the air at around 3500-4000FPM. As you drop below 3000FPM heavier chips tend to hang in the vertical airstreams and there is a danger of clogging if the velocity gets too low. At 800CFM the internal velocity just happens to be 4074FPM which is about bang on what we need and if you keep the SP losses low a normal 2HP DC with 12" fan will easily maintain the proper duct velocity.

3)    BUT MY DC INLET IS SMALLER THAN 6"?

You should not size your piping based on the size of the DC inlet. It is more prudent to size it based on the chart above and your ACTUAL fan diameter. Air will compress and squeeze around a restriction with a minimal SP impact but if you make ALL your pipe to the smaller ID there will be a large price to pay in terms of SP and as we have seen, this will kill your CFM. If you have an 11" or larger fan you should stay with 6" pipe to as close to the machine as possible and keep the use of flex hose to a minimum. 6" flex is also available that will make further improvements over 4" or 5" if you must use flex.

4)    SHOULD I RUN 6" HEADERS AND TAKE OFF WITH 4" TO MY MACHINES?

Do not reduce the size of your pipe as you get further away from the blower! As near as I can figure this idea has migrated from large industrial type installations. In BIG plants they may have dozens of small lines (6") and the systems are typically designed to have ALL the lines open at the same time! If you follow the path of the ducting from the furthest point away to the blower inlet you will find that the main header ducting keeps getting larger and larger as it approaches the inlet of the blower (this is also viewed as REDUCING as you move AWAY from the blower). There is a valid reason for doing this as I will try to explain. Let's assume the small drop lines to all machines are 6" and are carrying 800CFM. At the furthest point from the blower there is ONE solitary line. As we move toward the blower more & more lines connect to the header, each carrying 800CFM. With 5 of those 6" lines the CFM in the header is now 4000CFM so the pipe obviously must be big enough to handle 4000CFM. As we move closer still more and more 6" lines join the header and it must be upped in size again & again. Assume we needed 24 of the 6" lines for a plant that's 19,200CFM! They would stick in a blower capable of at least that plus some margin of safety so the system can run quite happily with all 24 pipes open. With big diameter blowers come big CFM numbers but also BIG SP numbers. A big industrial blower can easily have 20-30" SP or more which offers a lot more flexibility to the designer than we have with our little fans. These systems are in a totally different league from your 1 man shop DC system.

In our hobby systems we usually have just ONE blast gate open at any given time, primarily because we usually don't have the blower capacity to handle more and secondarily because we just don't need more than that. Because of this we need to treat each separate machine's duct line as if were the only pipe in the system. Because of this you should calculate the total duct pressure losses at 800CFM for each line of your system separately, treating it as the ONLY duct in the system and make sure your blower's expected SP limit is not reached. If all your runs of ducting stay below your blower's SP rating @ 800CFM then you are where you need to be. In other words, looking at our 11" fan example with 5"SP at 760CFM it is safe to say that if the SP from the ducting on any given leg is less than 5" then you will have around 800CFM. 

The only time I would consider reducing is if you have a long run and/or a low powered blower where the SP in that run is such that you will surely drop below 600CFM. In that case the vertical drop may be subject to clogging. To avoid this you could use a smaller diameter pipe which in turn will increase the internal velocity (FPM) and not let the chips precipitate out of the air stream. Be careful here though as using smaller ID pipe further increases your SP load and in turn reduces the CFM again! It is a balancing act that you should not need to worry about if you have a decent 2HP x 12" fan DC or better and a reasonable length of 6" ducting. What's "reasonable" you say? Well, for example; 60' of 6" with 90's, 'Y' and flex from our example above would have only 3.6" static pressure and a good 2HP DC is more than capable of handling that.

5)    BUT WHAT ABOUT ADDING A CYCLONE?

I have been talking about DC blowers specifically without a cyclone attached. A cyclone will have a BIG impact on the SP. In fact, it will typically eat up 3-4" SP without ANY duct work attached. One must take this into consideration if a cyclone is being added to the system. You can see that in the case of our 11" fan @ 800CFM and 5" SP that adding a cyclone that imparts 4"SP on its own will leave you only 1"SP  available for your ducting!!

It is widely accepted by those that I have encountered who have researched or experimented with hobby cyclone applications that a good 12" DC type fan is the MINIMUM requirement for a cyclone separator! IF you have a smaller 10" or 11" do not waste your time & money, Sell that DC and build a fan similar to what I did, you will not be sorry! Bill Pentz website has a couple options for building your own fan including the airfoil and the "Budget" blower. You will end up with a far superior blower for a reasonable cost when all is said & done. Another option is to just go an buy a bigger DC, say a 3HP or 5HP with 13" or 14" fan. While this is perfectly fine you will pay a pretty hefty price for the bigger DC and you can build one for MUCH less. Most of us are DIY types and will have no trouble building either of these blowers!

My Ducting:

I used 6" BDS (PVC) sewer & drain pipe wherever possible.

When I built my dedicated workshop I sunk 4" pipe in the floor for dust collection but that was before I met Bill and learned the truth about DC requirements.  You really need to shoot for 800CFM but with a typical hobby cyclone and any appreciable amount of 4" ducting, you will have a VERY hard time getting anywhere near this number. The desire to use this in-slab pipe is what led me to sourcing my blower arrangement. Since I have to work with 4" pipe I need a big SP capability in the area of 10-12" to squeeze 800CFM through my undersized 4" pipes. It should now be obvious that a normal 12" DC blower will just not cut it.

In theory my blower should be able to make my medium run of 11' of 4" pull just about 800CFM.  My shortest one (5 feet) will be up around 900CFM and my longest (28') will be down to only 500CFM @ 13" SP. 500CFM. This is just too low for catching the really fine dust. For this run I chose to bite the bullet and install an overhead run of 45 feet of 6" to service the far wall of my shop .

The piping is all done and the results right around what was anticipated.

With the 4" in-floor runs connected, the amp draw on my motor showed about 16Amps for the 11' run and 17Amps for the 5' run. By extrapolation this corresponds to about 1300CFM and 1400CFM respectively, far better than originally anticipated from the manufacturers fan curve.  Excellent performance for 4" ducts and all made possible by the 14" / 5HP blower. My test method is relatively crude so I may be out a far bit on these figures. Even so, if I was 40% off I would still be dead on my anticipated results from the system which is all I can ask for.

NOTE: Unfortunately the only measurements I am equipped to do is the amp draw on the motor so the CFM & SP numbers I am stating are extrapolated from the stock Cincinnati fan curve. I compare the actual HP draw as calculated from my measurements and find the relative CFM on the Cinci curve for that HP. Although amp draw is related to CFM, it would not be true to state that the numbers I have estimated are accurate. Again, I have done no actual CFM/SP tests on my cyclone and ALL data is derived from this fan curve.  These numbers represent what I consider at best an 'educated' guess. 

BLAST GATES:

I made a bunch of very low cost 6" blast gates out of scrap materials mostly. I have drawn a dimensioned CAD drawing of them and it's available on my website for FREE download in .PDF or .DXF format. Click HERE for the blast gates page!

The FILTER:

A Camfill Farr pleated cellulose air filter originally designed for intakes on gas turbines. This sucker is BIG!! For a bit of perspective here's a pic of it beside my General 350 tablesaw.

Specs are:

~ 300ft²

~ 13" diameter by  34" long!!

~ 99.4% efficiency at 0.5 microns

~ 1000 CFM at 0.5" SP

It was a real chore to locate them so here's the contact info for the Ottawa area. They do have offices in major cities so try your phone book or yellow pages first. If you can't find an office near you call them in Ottawa to get a local phone number.

Camfill Farr, Old Innes Rd., Ottawa, Ont. Canada.

Tel: 613-521-5555

Part# 125154-005

Price paid (2001): $64.00 CDN$ plus taxes.

The FILTER Enclosure:

If you would like a .PDF or .DWG copy of my filter enclosure drawing email your me your request.

Although some (like Dizzy) made a really neat installation by ducting the air from inside to outside of his filter, any cartridge filter will work better and be much easier to clean if you pass the air from outside-to-inside. This requires some sort of an enclosure, in my case a box. I put in a lexan window just for curiosity sake to see the filter in action and to tell me at a glance if I'm getting large particles if I let the chip bin over-fill.

The filter sits on top of a shelf that is dadoed into the box sides and has a 13.25" hole cut in it and on top of this shelf sits a second piece of 3/4" PCB with a rectangular cutout sized to fit the flange on the FARR filter. This piece locates the filter dead center of the hole for easier assembly.

The FARR has a 5/8" thick foam gasket on top. I located the dado in the sides to allow about 3/16" of compression of that foam gasket. That and the rectangular flange is all that holds the filter in place. Wing nuts allow quick removal of the filter. I originally planned to blow off the dust from the inside of the filter and remove it through the cleanout at the bottom of the box. In use this is not very practical as there is so little dust that gets to the filter there is no real need for a cleanout. Every so often I just pull the filter out, take it outside and fire up the leaf blower (shop vac with blower exhaust feature) and blow all the fine dust out that way. It's more effective than trying to do it with compressed air as you need a BIG volume to be of any use.

IS ONE FILTER ENOUGH?

It works for me. Now I don't argue that using 2 of these would be even better as there is a measurable drop in CFM (AMP draw) when you install the filter. The rating is .5" at 1000CFM but that's CLEAN pressure drop. Since they don't stay clean for long in our application the use of a second filter will buy you time between  cleanings. Honestly, with my extra powerful blower I only have ever cleaned it when I let the chip drum overflow and the filter box gets half filled with shavings... DOH! Don't laugh, it WILL happen to you too:) Bottom line, if you have the room and budget by all means put in 2, if not, one filter will work nicely for you as well.

Electrical:

The fact that I used a 5HP motor meant my old 220Volt, X10 remote would not live long if I tried to spark this baby up directly. I ended up buying a 30A dedicated purpose contactor for about $50 that had a switching coil @ 220V. I put the contactor in a small hinged lid metal enclosure, wired the switching coil to a 220v cord and plug which then plugs into the X10 module. Works like a charm!! Dedicated contactors vs magnetic starter, which one is best?? While a mag starter is the best it is also the most expensive and in my case I weighed the cost difference and came up with the following...

The dedicated purpose contactor at about $50 CDN is about 1/3 the cost of a magnetic starter. The life of the contactor is rated at 500,000 cycles. On average shop use of 2-3 days per week and estimating about 30 on/off  cycles per day (that's 60 contacts total) will mean 9360 contacts per year.  Do the math and at that rate it will last over FIFTY THREE YEARS! Since I can buy three of these for the price of ONE magnetic starter it is pretty obvious why I went this route;)

$$ COST $$

In total the cost for this project without the ducting has been between $900 and $1000 CDN. Considering the price of DC's it's a good deal cheaper than a 5HP (running $1500 @ Busy Bee) and even a 2HP at around $500 with an aftermarket bag is barely half the price. I could have built Bill's airfoil impeller for about $150 less cash than mine so for a properly sized 6" duct system you could get away for under $800 complete.

Final Impression:

This thing SUCKS! It pulls harder with 3 gates open than my old 1.5HP, 10" fan DC did with 1 gate open! As compared to my old trashcan lid the cyclone separator is absolutely fantastic! I started testing it with the filter not even attached. I fed half a barrel of shavings and sawdust into it and I could see NOTHING leaving the blower outlet! After upgrading to a 45gallon barrel and empting it 4 times I have to say I am even more pleased with the operation of my cyclone than ever. I can open at least 2-3 blast gates (4") at once with no noticeable drop in suction! I get absolutely ZERO chips coming back at me out of my 15" planer, even when hogging off full width and depth! There is no tendency to clog in the cyclone due to my "short" 20" cone however I do hear some chips swirling around the cylinder walls that won't drop into the barrel until the cyclone is shut down or more chips come through and help carry the rest down. Regardless, I get NO large particulate in the filter box whatsoever. It even does a decent job collecting a great deal of sanding dust before it reaches the FARR filter. 

Still have not bothered to insulate it yet. Guess the noise can't be that bad;)

In a word the cyclone is Remarkable!!!!!

When I first fired up the cyclone I opened the blast gate at the emptied the base of my cabinet saw which had been used for about 2 months cutting particle board and plywood with NO dust collection at all and was pretty full! I took out the filter and I could barely detect any dust on the filter at all! Amazing! Most importantly I know there is ZERO harmful dust coming out the outlet of that filter so I can rest assured I'll be breathing easier in the shop from now on.

This has to be the most useful project I have done for the shop bar none.

I totally recommend building or buying a cyclone over a standard DC any day.

Even if you buy a retail version like the Woodsucker or find someone to do the tin work like I did or even buy a prefab cyclone and convert it to cartridge filters it's worth it for your health.

I see Woodsucker now comes with a cartridge type filter. 

DISCLAIMER!

USE THIS SITE AT YOUR OWN RISK! 

The information and links contained in these pages is believed to be accurate however, neither I (Steve Cater) nor anyone associated with the links on this site guarantee any level of accuracy and will not accept any liability for damages to persons or property from the use or misuse, either accidental or intentional, of any information contained herein. It is the users responsibility to verify all information for accuracy, usefulness and safety.  Do not attempt anything that is beyond your skill level and if you don't feel comfortable with something, DON'T DO IT!