an easy-to-build small cyclone system that might work out very well for the entire place

[Bob Hammond]

Hi,

This past summer's flood gave me an 'Opportunity' to rearrange things in the basement shop, and one thing that needed change was the dust collection system. I'd built my first cyclone in the '90s before they were common (see in the library), but after reading Bill Pentz' thoughts, I agreed that my single-stage Jet DC-650/cyclone was marginally effective at best. More than that, I needed dust abatement in other areas that were remote from the main area. So I built this mini-cyclone system that seems to work well, at a total cost of about $75 (raw materials, vac, and HEPA filter, but without the stretchy hose). I think I'm going to abandon the old ducted system and use the Jet DC with the sub-2-micron filter as a general aircleaner. Instead I'll build several of these with fixed mountings, with each serving 1-4 machines.

In brief, the dust passes through the hose into the cyclone (6" diameter x 7" height, with an 18" funnel) then to the white collection bucket, and then the separated air enters the grey bucket with the 'buckethead vac' where it passes through a HEPA filter and thus back into the room.

Now I know what you're thinking -- when it comes time to clean the fine dust from the grey bucket, it's going to be a mess. Ah, we'll see: I put a funnel inside the grey bucket too, so that when the motor is shut off then the fine dust will fall down through the cyclone into the white collection bucket. Hmm, I've been wondering if I could help the fine dust fall by applying a very gentle reverse air pressure and few judicially light taps on the motor unit.

[Bob Hammond]

Of course, I took some photos during the construction. As soon as I can shrink them to 150k and write up a description, I'll post them.

[Bob Hammond]

diameters cut: cylinder parts at right foreground, funnel parts left background

(Sorry, I can't seem to arrange the pics in the proper order!)

Hi, here's the details.

While reviewing shop-vac cyclone systems that I saw on the internet, there were a few things that I thought were not optimal. Most appeared somewhat bulky and unstable to move around, and usually the plumbing connection between the vac and the cyclone was likely more complicated and longer than I thought necessary. So I decided to make a wall-mounted system that is stable, compact, and with minimal plumbing.

I lack the fabricating skills and tools of a sheetmetal worker, i.e. drafting patterns for shape & seam allowances, and folding the seams and soldering them. Besides that, a sheetmetal worker usually would construct the cyclone first, and then attach the finished cyclone to a supporting structure. I decided to use the support structure as an armature to shape the cyclone. I made the cylinder diameter 6", and the funnel length 18", and the inlet was 2.5"D and the outlet 3" D First I cut 8"x9" rectangles, marked the centers, and then cut out the centers.

[Bob Hammond]

After fixing the supports rectangles at their stations with pocket screws, then I cut the sheetmetal for the funnel to the approximate shape and inserted it into the support. I then traced around the support to mark the exact cutlines, removed the sheetmetal and cut it. Then I put it back in the form, and used aluminum duct tape to fasten and seal the seam (this makes a smooth seam, and is strong enough because the supports hold the shape.) I fitted the sheetmetal for the cylinder but waited to tape the seam until the tangential inlet hole was cut out. (The sheetmetal on the bench is the approximate shape for the funnel, to be used on the next cyclone).

[Bob Hammond]

Shaping the inlet is the most difficult part. I found an old textbook 'Sheet Metal Work by Neubecker that is freely availble online (interest to look at!), and learned how to draw a pattern for the inlet tube (p. 136). I cut the tube, and then held it up to the sheetmetal to trace the hole's shape, and then I removed the sheetmetal and sheared through the metal with utility knife by placing the metal over the crack in the bench. I then cleaned up the hole with a hammer and file, and refitted the metal into the supporting form.

[Bob Hammond]

The inlet tube was attached with Devon Plastic Welder epoxy, which worked surprisingly well. I first abraded the plastic and metal with 100 grit paper, and carefully degreased the metal. With other epoxies, especially putty types, I often smooth it with spoon or gloved finger that I dipped in denatured alcohol, but since this is the first time that I've used this formulation, I didn't do so.

After this, the rest of the construction was straightforward. I caulked around at the wood to metal transitions, and also between the cylinder and funnel assemblies before they were screwed together. The same was done for the plastic fittings between the cyclone and buckets. To accommodate the larger diameter of the buckets, I made standoffs where I screwed the cyclone to the wall.

[Bob Francis]

Thanks for posting this Bob.
I like the wall mount and more slender aspects a lot.

[Bob Hammond]

In the first post, you can see a 'temporary' toolcart that I built 20 years ago when I was putting an addition on the house. Somehow it's been so handy that it's still here, in part because the sloped sides maintain a stable, safe center of gravity. This made it less 'tippy' when it is moved around on unfinished floors and through doorways, and it actually makes it easier to see and reach the tools too. I'm now about to build a new version, that carries not only a toolchest with fitted tool holders, but it also will contain a cyclone/vac system, the architect's lamp, and a couple of other conveniences.

[Bob Hammond]

I discovered a limitation that didn't occur to me before. The mini-cyclone's outlet became clogged by a paper towel that I'd sucked up. Since there is no air pressure/flow from the cyclone into the collection bucket, then all debris, e.g. paper towels, must simply fall by gravity into the bucket. The big cyclone that I built back in the '90s has a 5 or 6" outlet, so it passes larger debris easily. I wonder if this might become a problem with a larger volume and size shavings from the planer or maybe the jointer.

[Bob Francis]

Seems to me that any of the high volume sawdust makers would be likely to clog the vac assembly.
Saws and sanders not too bad but planers or drum sanders I'm thinking would be a heavy load.

[Bob Hammond]

The feedrate and depth of cut of the materials will be important; going slower and taking light cuts usually produces the best results anyway. But perhaps I'll keep the big cyclone/DC around for a while longer, and dedicate it to the high-volume machines with the shortest possible ductwork.

[bill pentz]

Sadly, almost all who first start using a cyclone are so happy with how well they work compared to their prior dust collection efforts that it often takes years before they start looking for refinements. I know a bit about designing woodworking cyclones and suggest that if you want to make something similar you would be much better served to follow the free plans shared on my Cyclone and Dust Collection Research web pages http://billpentz.com//woodworking/cyclo ... e_plan.cfm. I have been doing research and woodworking cyclone engineering since 1994. I solved the problems that almost all cyclones had with their cones plugging and not dropping all the debris into the collection bins. I solved the airflow problems that robbed most small shop cyclones of roughly one third of their airflow. I also came up with much more efficient blower and impeller designs to better power cyclones. Today, all but JDS and Laguna now use my innovations. I went further and also figured out how to reduce internal turbulence that kills fine dust separation. I also figured out how to get at least six times better separation of the fine airborne dust that constantly clogs and quickly ruins fine filters. These refinements are well worth the little extra work to upgrade a basic design as this to something that will make a big difference. Most who use my latest cyclone design find that they go from having to replace their fine filters every three months of full time woodworking or yearly for most small shop workers, to going six or more years before their particle meters show they need to do a filter replacement. I strongly recommend making my 18" diameter if you are using a dust collection blower up to 5 hp and my 6" vacuum sized cyclone if working with a shop vacuum.

[David King]

Hi Bill,

A real honor to have you find this thread and stop in at the MIMF. I now have a clue as to why my JDS cyclone is such a worthless piece of junk. Thanks again for providing such a wealth of free and accurate information to help us wood workers around the world and to bring the dangers of fine wood dust to our attention.

[Bob Hammond]

Thanks for the critique and suggestions. I'll review the material again.

[Matthew Lau]

Hey Bill,

Good to see you here. Build any instruments?
I'd love to see your work, as I've had a lot of respect for your cyclone info for years.

[Bob Howell]

I found plans for this in "Shop Notes" Dec 1993 and built it so I could handle a thickness planer. Its just made of sheet metal found in HVAC dept at HD. I sure better plans are around but this was so easy. 1 1/2 hp fan on top. The bag was made from singed polyester bought by the yard from an industrial supplier in Chattanooga Tenn. Got a nice lady on the phone and she sent me 2-3 yds for chump change. Told friends 2-3 years later and on calling they said they stop small orders. It is surly available somewhere.. It is thick as old wool blanket and stops most everything. Dumps into a 5 gal bucket and only fills up when I forget to empty the chip collection box at the bottom. I've emptied it 4-5 times since 93; but it is

a mess to do. The piping is another issue and books around explain it.

The chip box fills up every 6-12 months.

The bag is glued up using construction cement, Liquid Nails. A 15" sq of plywood forms the top which the material is attached to. Shoe shop man said it was too thick.

[Bob Howell]

I want to add this is just the first step in dust control. Working out collection at each source of dust and the general air filtration is next, but box fans and furnace filters are simple and big help . 5 years ago I moved all sanding machines outside under cover because I could never collect all the dust.

[Eric Baack]

I have a Thien baffle setup on a 50 gallon drum and it works very well. I just run that with a shop vac to pull dust/chips off of my cnc and it does an excellent job both of keeping the part clean and keeping all but the finest dust out of the shop vac.