The wooden impellers even at 1725 RPM kept blowing up so were abandoned as just too dangerous. Most vendors do not want to build a system with this much risk, so few will use a caged impeller. With fine dust spreading rapidly in any shared air and so easily carried on our clothes, skin, and hair we tend to contaminate all areas we visit while woodworking including our homes and vehicles. For those unable to afford the time or money to invest in a cyclone-based system with good cartridge filters, I recommend buying one of these cartridge filtered based dust collectors, or better yet, modifying your own dust collector to use a better cartridge filter (see Adding a cartridge filter to a dust collector). Finding these units too rapidly ruin filters and knowing I cannot blow the air outside, I went back to the physics and engineering to build a better cyclone. That machine has a hood that needs to be placed and shaped just right to control then capture the dust as it is made. This works great in large commercial systems where automatic bin emptying systems keep the cyclone bins clear. My respiratory doctor already knew air cleaners are worthless for protection while you work because they take hours to get the air clean enough to breathe so you still need to work wearing a good NIOSH approved dual cartridge filtered respirator mask. I also had to engineer my own blower then test various motor and impeller combinations to power my cyclone and move enough air to ensure moving the air needed at our larger tools for good fine dust collection. What I am saying is you need to follow the airflow recommendations for your stationary tools. The spinning blades sling the air off sideways with considerable force (note arrows in picture show impeller rotation direction). You used to have links to fellows who made their own blowers and impellers, both wood and metal. With the rates to ship larger items by truck up to five times higher than through the post office, FedEx and UPS, most small shop cyclones end up being compromised in both size and weight to conform to the lower cost shipping restrictions. Download Free Dust Separator Cabinet Plan. Regardless, almost all dust collectors and most cyclones use material movement blowers because of the problems with caged impellers discussed previously. Most of the time we should not be filtering but instead blowing our cyclones outside. With most small shop woodworkers and small shop vendors knowing little to nothing about fine dust collection, small shop tool and dust collection vendors stayed stuck in "chip collection" technology. Cyclones blast incoming air onto the cyclone wall to knock the light material apart from the heavier. In practice a cyclone with a big air leak, open dust bin, or full dust bin ends up pumping everything right through the blower. It turns out that same blower housing is used on the Jet 2 hp DC-1200 blower which uses a 12" diameter instead of your current 11" diameter impeller. I personally built my airfoil blower with clear polycarbonate plastic sides that let me regularly inspect the impeller for build-ups. It minimizes the air turbulence from the parts to dramatically reduce resistance and motor horsepower requirements while significantly increasing fine particle separation efficiency. Better quality motors are totally enclosed fan cooled (TEFC) motors. My friend Jim Halbert came up with his neutral vane that helps traditional outdoor cyclones to move air a little more efficiently, but this does not help much with airborne dust separation. Heavy impellers are hard on motors when coming up to speed. The flex hose or ducting then connects to a blower. Although tough, the material handling impellers made with straight vanes going out from the center creates what are called radial blowers. All of the expert firms who guarantee customer air quality say we need a full 1000 CFM at our stationary tools to get good fine dust collection. My airfoil had incredible suction and the stalling was not a problem until I added a full set of ducting in my shop. What should I do? Our buying a blower big enough to overcome that resistance ends up with our paying for a much larger motor that barely gets used. It also can be expensive to blow our heated or cooled shop air outdoors, so most use filters to return cleaned air to the shop. Dusty air builds up a cake of dust that will overheat the motor resulting in eventual motor failure and possibly a fire. This poor separation also causes our shops to build up dangerously unhealthy dust levels.
Dust collectors blow a very fast moving stream of air into their filters.
Airspeed is measured in feet per minute (FPM). This plugging kills our needed airflow, plus drives the pressure up enough that the fine silica (glass) particles that trees use for strength end up getting pushed to cut and tear their way through turning our fine filters quickly into wide open sieves that pass most of the finest unhealthiest dust. The dust chute is sealed tightly to the bottom of the cyclone with no air leaks to stir up the collected dust. These filters almost always start off doing a much better job and their much smaller fibers allow more airflow, but soon these filters fail. Since it is illegal to exhaust outside in my area I must use filters. Look for a separator with a foam-rubber or soft-rubber gasket that seals the lid against air leaks, ensuring maximum suction. Almost all go with use of a cyclone separator as the only other really viable option other than buying a commercial dust collection system. As vendors moved over to using more cartridge filters they were forced by early filter designs to flow the air from the outside in. Although far more efficient, these designs come with costs. If you go to the publisher's web page it runs about $4 less expensive than buying a copy from eBay. In terms of noise, you are better off with material movement impellers to make that spacing as much as 50% more. Chip collection picks up the same heavy sawdust and chips we would otherwise sweep up with a broom. Most small shop dust hoods are poor quality, use too small of an inlet port, and will have to be rebuilt to protect, control, and deliver the dust. A properly sized trashcan separator will separate off roughly 85% of the dust by weight. I learned that in spite of many confusing terms and more than a little misleading vendor information, we each understand airflow far better than you may realize! With any solid-material bin, we suggest you cut a small view window near the top and attach a piece of clear acrylic or glass.
The typical small shop vacuums that we get from hardware and box stores pull about 30 water column inches of suction and use 1.125" diameter hoses. An impeller is a flat disk with vanes or blades attached to one side. The increased pressures as these filters get dirty pushes the fine dust through the filters tearing open the pores. Small shop blowers are direct drive with fixed speed motors (normally 3450 RPM with 60 cycle current) so need a larger impeller with sometimes a bigger blower housing and motor. Often upgrading impellers immediately voids our dust collector warranty because running a big impeller without enough resistance will quickly burn up a motor.
These designs don't even do a good job of chip collection. Unlike the Festool units these do not need the expensive paper bags that constantly need replaced and still produce far more pressure than almost any other small shop vacuum. Airfoil impellers have one more significant drawback because they stall if the pressure gets too high. Heavy chips in that air stream punch holes in the filters eventually making them too open. Longer cyclone cones also provide better fine dust separation, but the cone needs to be the right proportions to keep the airflow from either sucking collected material from the bins or holding the dust too high where it eventually causes plugging. The problem with cyclones is not just making their normally less than good quality copies. Blowers do the most work with an open unlimited amount of airflow and the least work when all is closed off and there is no airflow. We are proud of the quality of our products, and we stand behind them 100%.
The low-profile-type units rely on the air space inside the collection bin to create the separation action. Each, We proudly stand behind all of our products. I am a retired engineering university instructor, inventor, and pretty senior engineer who dislikes giving out my time or advice to those who are doing foolish things that I know are unhealthy for them and their families. Almost any blower shroud will work to move air. Otherwise, any small ducting runs or restrictions will get severely kill the airflow just like partially opening a water valve. And, pressure is measured in terms of suction pressure, known as static pressure. This makes for some incredible maximum airflow test results as reported in the woodworking magazines, but in testing with an amp meter at these airflows most of these units will burn up their motors within minutes. As a result, much of the advice from fellow small shop workers and even small shop vendors is geared to collect the same stuff that you would get with a broom. Too much ducting, large cyclone, etc.
Unlike commercial units, most small shop dust collectors use a lower bag that is also a filter to help make up for the filters being so small in area. In short, if you use small shop vendor filter bags, your dust collection system needs to be outside. Although just about any cyclone design will separate the heavier particles needed for venting just the airborne dust outside, it takes considerable engineering skill and work to build an efficient indoor fine dust separating cyclone design that will work with the normal challenges found in small woodshops. from clogging and punching holes in our filters.
Their disadvantages are they cannot take direct material hits and will clog quickly unless you use a pre-filter or separator. The resulting very high turbulence breaks the heavier and lighter materials apart. Designing a good fine dust separation into a cyclone compatible with indoor use with fine filters requires a whole different design and considerable work. Almost all small shop dust collectors use an electric induction motor with its shaft directly turning an impeller that turns at about 3450 rotations per minute (RPM). Three-phase motors don't have this problem, as they don't need the capacitors to shift the fields for startup. A cone too long ends up plugging because the airflow keeps the dust from dropping. Heavier particles get trapped in the slower moving air and gravity slowly pulls these heavier particles down. Most sized with 3 hp motors do not move the air needed for good fine dust collection at our larger tools. Even when protected by a cyclone our impellers can be hit with heavy blocks and debris whenever we have a bad air leak or full collection drum. 
In most commercial dust collectors the dirty air after the bigger chips and blocks are removed by the separation ring goes up into a large bag filter. For good dust collection and noise control we need a well engineered blower housing. Custom Doors, Drawers & Glass Accessories. With a good cyclone almost nothing goes into our filters most of the time. He did a great job both on his design and special more efficient blower.
Collect and store dust in metal cans to avoid fires. The smaller the cyclone the better the fine dust separation, but it takes a much bigger and more powerful blower to push air in smaller circles. A vendor that makes a dust collector that works well for a large shop full of ducting will have their dust collectors burning up when used in a shop with minimal to no ducting. Eventually I added a weighted trap door that opened when the pressure got too high to keep my airfoil blower from stalling. These fans sit inside ducting and push the air through. Because filter material makers also give the filtering level on fully seasoned filters, many vendors claim that as their filtering level. Much of the safety and efficiency of a blower as well as how much noise it makes depends upon the shape and design of its housing. In addition to the airborne dust cyclones also blow right through things like strings and long shavings that have lots of surface area. For lots more information visit my Ducting Page.
You can order that bigger impeller from Jet directly. Air coming into the blower is controlled by the size of the blower opening. Blowing out to in requires a filter box to route the air. Most fans look like common table, box and ceiling fans that use fan blades to push air through the blades. If the blower is on the clean side of the filters, a much more efficient clean air caged or airfoil blower can be used. These odd shaped pieces act like sails and go right through our cyclones. Cyclone separators can go longer between dumpings because all separation occurs above the collection bin. Although the most powerful and perhaps the nicest are the larger Festool vacuums, I instead recommend the slightly less powerful but still expensive big Fein vacuums with the cartridge filter. I also added quite a few additional improvements to these types of designs detailed on my "Cyclone Modifications" page that many vendors are now copying, but even with all these enhancements those remain outdoor units in my opinion only suitable for blowing the fine dust away outdoors with no filtering and no return of the air into our shops. With that all said is a filter box what I recommend? Let Mother Nature be your co-designer as you build dazzling projects with wavy edges, bristly burrs, bark inclusions, and other flaws that give wood a look of unrefined beauty.
The heavy all poly felt material is great stuff and exactly what I recommend in a 30-micron material for outside use. We like steel collection drums for their durability, but they're costly and can be heavy to dump. Dust collection blowers come in two flavors, material movement blowers or clean air blowers.
I found four industrial suppliers carry them. Dust collection firms have for over fifty years relied upon the extensive agricultural cyclone research to size and configure their cyclones to separate airborne dust from heavier material. Using a small separator with a large 3-hp dust collector could overpower the separator, pulling large debris right through it or collapse it. Because the bulk of debris never reaches the collector's small collection/filter bag, an affordable 4" portable collector, such as the 1-hp unit shown in the opening photo, operates more efficiently than it would without the separator. Also, woodworking makes so much dust and chips that buying a small vacuum means you spend lots more time emptying the vacuum. An impeller jam not only ruins the impeller, it often ruins the motor by slamming it into such an abrupt stop that the internals slide on the shaft. We were unable to find perfect garbage-can matches for two common lid separators, so buy at your own risk. Filters in dust collection were originally used in outdoor systems to capture chips and larger sawdust particles that don't just blow away into the outside air. star silver series air dryer chillers developed efficiently innovative cooling called range Because air will barely compress at all at dust collection pressures you also need to have large enough ducting to carry this air volume. The impeller turns in a spiral shaped blower housing that needs to be very smooth to minimize the disruption of airflow. I know because one of the test units I was evaluating blew and exploded right through the 18 gauge steel blower sidewall. The sucked air generally enters the side of the collection tank and is often directed to swirl around inside the drum causing a little cyclonic action that minimizes the amount of dust that goes to the filter. Many woodworker forum posts and some magazine reviews agree his Jet is one of the best. Blessed with an eye for potential, David Willett looked at his dark, unfinished 112-car garage built in 1956 and saw the bones of a workshop. If you had to recommend three, which hand planes should I start with? As we move from "chip" to fine dust collection, the chances of making a bad blower mistake increase greatly. My concern is the offset of the impeller in the housing, I know it is not centered, but where does it go? The problem is when brought indoors these types of filters which are still the standard on most small shop equipment are "dust pumps" that fill our air with huge amounts of fine dust. Although this works well, letting stuff slip off the impeller blades also lets the air also slip off hurting blower efficiency. Tilting the vanes away from the direction of rotation creates what are called backward inclined (BI) blowers. I trusted what I believed to be reputable small shop vendors to provide a cyclone and filters that worked as they advertised. An air cleaner is set up to stir the whole volume of air in a room. It turns out that the airspeed generated by sucking air falls at about the same rate as the area of a sphere grows, roughly 4 times Pi times the distance squared. This keeps the airfoil blades from stalling but when that door opened it so reduced the airflow at my distant machines I got very poor collection. The result still left me with a cyclone that separated so poorly I spent more time cleaning my fine filters than doing woodworking. Most of these tools require a full 1000 CFM for good fine dust collection. Vacuums use universal motors turning at very high speeds, typically 18,000 rotations per minute and faster. Each wanted over $250 for quantity one plus a hefty shipping and handling charge. The impeller is a spinning large flat disk with vanes. Almost all dust collectors and cyclones use a special fan known as a centrifugal pressure blower. this link is to an external site that may or may not meet accessibility guidelines. Dustopper separator kit, no. Divide that by 3 to get the minimum sized exhaust fan, but more is better.
In practice the airflow inside a dust collector is so violently turbulent that chips and even small blocks constantly crash into and frequently poke holes into our filters. Vacuums only provide good dust collection for tools engineered from the ground up with good fine dust collection built in, meaning the tool protects, directs, and delivers all the fine dust right to the vacuum connection before it can be blown away by air streams from our blades, bits, cutters, belts, motors, sandpaper, room air currents, etc.
Not only is airborne wood dust unhealthy, larger facilities create potentially explosive dust to air ratios so it is important to separate off the airborne dust to avoid explosions. Building a filter box is fairly easy. Squirrel cage blowers have a round slotted cylinder that sucks the air in from the sides into the center then pushes it out a blower outlet. Vacuum fans are called caged impellers because they put the fan blades (spirals) between a top and bottom plate that keeps the air from escaping while turning. That makes airfoils inappropriate for any shop with considerable ducting, an inefficient cyclone, or plugged filters. vapour separator seperator knockout Unfortunately, this fine dust problem does not just go away after we finish our woodworking, but instead builds to often very dangerously unhealthy levels. Most small shop "fine" dust collector bags pass between twenty to thirty times larger particles than small shop vendors advertise until so clogged they barely pass air. Almost all dust collectors instead use material movement blowers with impellers that only get a maximum of about 45% power efficiency. We still need larger dust collectors and cyclones because vacuums do not move enough air volume to be good for capturing dust from machines that emit dust over a larger area. 
pressure will hurt your filters!). Many said making my design to use a smaller motor was a waste of time because fine filters only need cleaned a couple of times a year with existing cyclone designs. As of late 2005 not one mainstream small shop cyclone vendor offered a 2 hp or smaller cyclone that moved the air needed for good "chip collection". Vacuums do an excellent job of cleaning up small areas and vacuums are the only way to get good collection and avoid some little known fire risks. The blower connects either through a muffler or directly to the filters with a cleanout below to return clean air to your shop or the blower vents outside. The less honest vendors make things worse by making up their own filtering claims and forgetting to include the needed airflow information. For maximum health protection we need to use cartridge filters rated by a certified lab with ample surface area. Then the internal airflow and turbulence is maintained to keep the light material airborne so it can blow out the top of the cyclone. Fortunately, most shop vacuum brands can be reconfigured with these somewhat pricey fine cartridge filters. These designs known as either material movement or material handling impellers limit the buildup of wood strings, shavings, and other material that could cause the impeller to become unbalanced. Oneida 4" Super Dust Deputy deluxe cyclone kit. Government standards left hobbyists, the six out of seven small shop woodworkers, and small shop vendors that sell us our tools and dust collection with no standards or oversight except what we force with our purchases. Unfortunately, this leads to some interesting advertizing claims where many firms ignore the airborne dust and simply claim 99% separation efficiency in spite of their cyclones freely passing close to 100% of the airborne dust and odd shaped things like long shavings right through.