Created: August 9, 2002
Updated: May 15, 2008

DC Cartridge Conversion

Table of Contents

1. Challenge
2. Warnings
3. Basics
4. FixYourTools
5. Good Solutions
6. Lesser Solutions
7. Cartridge Filter Installation
8. Disclaimer

Challenge

Hey! I already am in enough trouble with the family for spending so much on woodworking tools. Can I convert my existing dust collector to something safer without breaking the bank?
Humm... Don't want much do you? Putting on my shop apron..

Just about any hobbyist dust collector with a real airflow of 450 CFM will do a superior job of collecting chips and keeping our floors clean. Unfortunately, going after the chips does not protect your health or the health of those close to you. The National Institute of Health (NIH), OSHA, and similar organizations in countries throughout the world agree that the fine wood dust particles that go right through most hobbyist dust collector filters, including fine filters, are unhealthy with long-term exposure known to cause sensitivity in almost everyone. Many develop more serious problems including asthma, emphysema, allergic reactions, polyps, and even cancer. Government regulations long ago recognized that chip collection does not protect workers amply, because ongoing medical studies show those who work in shops with good "chip collection" still have such high long-term exposure to fine wood dust that almost all eventually become ill, some seriously. We now have government air quality standards to protect workers.

Hobbyists must fend for ourselves because we have no standards or government protections. The belief that hobbyists receive little exposure compared to professional woodworkers is wrong! Testing in shops using the same tools used by hobbyists shows five to twenty times the dust levels found in most commercial facilities that put their cyclones and bag filter systems outside where most of the finest dust just blows away outdoors. My own shop with cyclone and fine filters looked great with almost no buildup of fine dust on my tools at all. Unfortunately the fine filters I used created a false sense of security because these filters were passing most of the fine near invisible dust. My trapping my shop air inside without blowing all out, let that fine dust that lingers for months build up to dangerous levels. Any airflow from turning on my dust collection equipment, larger tools, and air compressor blew that fine dust right back into my shop air. With my shop connected to my home, the medical air quality testing I had done showed my shop and my home severely contaminated. It also showed my tools blew the finest dust all over before it could be captured. My clean looking shop tested at over the government maximums in terms of total weight of suspended dust. The testing I had done also looked at suspended particle counts, and those test results were scary. The finest particle counts in my shop were over 10,000 times those typically found in large commercial facilities that mostly blow their fine dust away outside. Clearly my tools launching dust combined with too open filters and trapping that dust inside made the air in my shop dangerously unhealthy! Although my inspector said mine was one of the cleaner shops tested, at these levels, just like most other small shop woodworkers that trap our dust inside, we often receive more exposure to the finest 2.5-micron and smaller dust in four hours of woodworking than a professional will in a year of full time work. If you do not think these finest lightest particles are anything to worry about, you might start with my Medical Risks information. Or, you can do your own Google search on “PM 2.5 health risks”. Sadly, almost all close to us also receive too much exposure. With the government maximums now under fire for causing most to eventually develop dust related health problems, this creates a serious concern for us. I strongly suggest doing the homework to make an informed decision on the potential risks.

Many wrongly think all you really need to protect yourself from fine wood dust is a good mask. A good mask only protects you while working. Few leave their masks on long enough. Using an air cleaner or even a modest sized exhaust fan takes about six hours to clean your shop air amply to take off that mask. Few also only put our masks on when doing dusty work not realizing that as soon as we turn on our tools, dust collection equipment or use our air compressors we immediately launch previously made dust back into our shop air. Because fine dust lingers for six months or more before breaking down or getting blown away, it just builds and builds in our small shops unless we figure out how to get rid of it. It travels in any shared air to go into our homes and offices, plus gets carried on our hair, skin and clothes to contaminate our vehicles, offices, and homes to affect all close to us including our pets for months. The only effective ways to control fine dust is to modify our tools to control the dust, move enough air to capture this dust at the source as it is made, then get rid of this dust. Our only other safe alternative is to work outside with a dust mask on! See my Doc’s Orders for specific recommendations. Collecting the fine dust at the source takes far more work and expense than chip collection. You need to move more air which requires a bigger dust collector blower, typically 2 hp and larger. My testing found only the Delta and Jet 1.5 hp dust collectors moved enough air with all other makers needing at least a 2 hp unit. To get rid of the dust, those units need to be put and kept outside with no air coming back into our shops. Unfortunately, many like me cannot put our dust collectors outside because it is illegal, makes too much noise for the neighbors, or is not practical to blow our heated or cooled air away outside. For us, we need to provide better air filtering. My doctor recommends only using independently certified 0.5-micron or better fine filters and blowing out our shops after major dusty operations to get rid of any accumulated dust. He says about the only way to get ample filter area is to use a cartridge filter. That cartridge filter should provide roughly one square foot of filter area for every 2 CFM if you use a typical paper polyester blend certified filter. If you use the more expensive thicker all polyester or special fine fiber blends, you can get by with as little as one square foot of filter for every ten CFM to do the filtering, but will have too frequent cleanings if you choose to use filters this small.



Warnings

1. Traditional bag type hobbyist dust collectors are more dangerous than if we went back to brooms and dustpans because these units are dust pumps that recycle the most hazardous particles.

2. Many woodworkers wrongly believe, as I once did, that fine filter bags would be enough. I bought a set of expensive fine filter bags and was proud of myself thinking I had done well, but all in my shop continued to be covered in fine dust. An existing lung injury from ages ago in the military combined with that heavy dust exposure to make me very ill. While recovering, I did a lot of homework and was pretty unhappy to find that many of these so called fine filter bags were rated by the makers. They could claim any level of filtering they want by simply clogging them with so much dust they won't pass air. Three different universities tested my fine filter bags. Each found that unlike cartridge dust filters built for industrial use with certified filtering capacities right out of the box, just like most older style hobbyist dust collector bags, my fine filter bags passed the same 30-micron sized particles all day until they were so caked with air they would barely pass air. With further homework I found a few good filter bag makers. You can call up American Fabric Filter and order up a big top replacement bag then get some thick plastic bottom bags from ShopSmith for about $8 and a nice cam action bag clamp to seal and hold that bag in place from ShopSmith part number 518393 for about $5.60 plus tax and shipping.

3. The good quality bags that actually provide their rated level of filtering are still not a good solution. Like cartridges, fine filter bags provide better filtering and much more airflow by using much finer filtering threads. Unlike cartridges, few bag sets have more than 30 square feet of surface area which is far less area than really needed to keep from having a constant cleaning problem. Cleaning wears out our filters making them more porous so they pass more and larger dust particles. With under one tenth the filter area and roughly double the cost, fine filter bags also have over ten times the resistance and need over ten times the cleaning to stay similarly effective. Resistance kills the airflow we need to capture the fine dust. Cleaning takes time and quickly wears out filters.

4. Although a number of hobbyist vendors now offer cartridge filtered based dust collectors, my hopes for these units providing significant help collapsed. The best of these makers still only use a real 2.0-micron filter allowing most of the finest unhealthiest dust to pass right through. The fancy paddles, flappers, and other cleaning systems offered on these units are there because these units have a basic design flaw. They allow everything to blow right up into the filters. This means that the cartridge filters quickly plug and need constant cleaning. That tradeoff appeared acceptable to me at first until I continued my testing and found the cleaning quickly wore out the filters and the high velocity chips poked holes into the cartridge filters. With thousands of new larger holes after every use and the cleaner making that even worse, soon these fine filters end up passing all that the old dusty bags passed. You can tell when you have a problem when your shop again has a coating of fine dust everywhere. These units need a fine screen in addition to their more coarse support screen to block these hits and much finer 0.5-micron filters before they would get my blessings. Trying to protect a cartridge filter with a traditional trashcan separator does not work useless unless you strangle your collector airflow with 4" pipe. If you use the 6" ducting and 800 CFM that you need to get the finest unhealthiest dust, the airspeed will be so high it will scour the trashcan separators clean of all but large blocks. It takes a trashcan separator that is about 5’2” in diameter and 7’ tall to handle 800 CFM.

5. If you cannot blow the air outside, you really need a good cyclone separator to protect the filters, minimize cleaning, and maximize filter life. Typical early hobbyist cyclone designs are downscaled versions of the large commercial cyclones we see outside most woodworking facilities. These cyclones use very high internal turbulence to do a great job of separating the heavier dust and chips from the fine dust, then just blow the fine airborne dust away outside. This leaves most commercial cyclones actually getting around 85% fine dust separation efficiency. This makes sense because on average commercial woodworking dust is roughly 85% heavier sawdust and chips with about 15% fine airborne dust. This is near identical to the 85% dust separation by weight given by hobbyist trashcan separator lids that only work with smaller blowers. Unfortunately, separation efficiency creates another place where hobbyist vendors put out bad information trying to make their products look better than others. Testing almost any cyclone with nothing but heavy chips ends up with being able to claim near 100% dust separation efficiency. If tested with really fine dust, most hobbyist cyclones would get close to 0% separation efficiency. In the late nineties John Dillbeck spotted the idea of using an extended inlet to reduce internal cyclone turbulence and improve fine dust separation in an obscure cyclone article. He shared that information on the Badger Pond Internet woodworking forum and not long after many hobbyists began modifying their cyclones to improve separation efficiency and use less power because they were not generating so much internal turbulence. Someone coined the misnomer “neutral vane” and the extended inlet has been called this ever since. Putting an inefficient cyclone on a very fine filter is not a good idea. Finding my finer filters put on a hobbyist cyclone quickly plugged those fine filters. Plugged filters kill the airflow needed for good dust collection at our larger tools, plus filter cleaning wears out filters. Wanting more separation efficiency I went back to the swirl tube physics, came up with a better indoor cyclone design that was far more efficient both in terms of separation efficiency and horsepower usage. I shared my research and designs. Now most of the larger hobbyist vendors provide a neutral vane or some of my later suggested enhancements, but as of late 2005 almost all hobbyist cyclones still send about half the airborne dust into their filters except for the WoodSucker II and Clear Vue Cyclone that uses my design. Too many hobbyist cyclone vendors now avoid seeming to have a problem by simply selling their cyclones with very open filters that freely pass the dust their cyclones cannot separate. One goes so far as to say their design is so efficient that most only need to clean the filters a couple of times a year. A good cyclone design will remove over 99% of all wood dust and chips by weight before they get to the filters.

6. Upgrading to a cyclone can be expensive, so many want to add a cartridge to their existing dust collector to keep from recycling the unhealthiest fine dust. Stopping fine dust recirculation helps, but is generally not enough to make your shop air safe because most dust collectors move too little air to capture much of the fine dust as its source. Considerable careful engineering and testing shows most of our larger hobbyist sized tools need hood upgrades and a real 800 CFM to effectively capture the fine dust as it is made. Although many dust collectors claim far higher CFM output, the vendors make their ratings with no hose, no duct, no bags, no filter, and often a special hyperbolic inlet to maximize airflow. Under real working conditions, most hobbyist dust collectors provide about half their advertised airflow, far too little to effectively capture the fine dust at its source. Except for the Delta and Jet 1.5 hp, none of the dust collectors I tested moved enough air for good fine dust collection with anything less than a 12” diameter impeller and 2 hp motor. The Jet and Delta work because they use a more efficient larger impeller than the other units I tested. Unfortunately, getting a 2 hp dust collector does not ensure moving the needed 800 CFM. A number of the 2 hp collectors I tested including the Harbor Freight 2 hp, Grizzly 1029 2 hp, Reliant 2 hp, King 2 hp, and PSI 2 hp dust collectors failed to move the needed 800 CFM due to small impellers, poor blower designs, and restrictions. All of these vendors have since upgraded their 2 hp dust collectors since my pre-2001 testing and claim better performance now. There are far too many to test all over again, but if you do not see a 6” blower inlet, 5” blower outlet and at least 11.5” diameter impeller, then I seriously doubt the real performance at typical shop ducting resistance loads will provide 800 CFM. Although you can significantly reduce the fine dust in your shop air with a cartridge filter upgrade, you are not going to collect that fine dust at the source unless you have a big enough dust collector and upgraded hoods.

7. With it only taking the slightest breeze to move fine dust, many don’t understand why collecting fine dust takes double the airflow needed to collect the chips and sawdust you can get with a broom. Airspeed when blowing falls off slowly as the air travels away. A stream of air can carry many feet before its speed falls so much that it will no longer move fine particles. This is not the case with sucking, because sucking pulls from all directions equally. This causes the airspeed to fall off at 4 times pi times the distance squared which is the area formula for a sphere. We already know how this works. Think about using a shop vacuum. Just a few inches away from a vacuum you can barely feel any air movement at all. To test this wet a finger and see how far you can move it from your lips and still feel blown air. Wet it again and see how far away you can feel sucked air. Most of us can feel our blown air as far as we can reach, but no longer feel sucked air just a tiny distance from our lips. The result is blown air can launch and keep fine dust suspended in our shops air for hours, but to get rid of that airborne dust we have to move a huge amount of sucked air. So in short we need good hoods to control the fine dust before it escapes then move lots of air to capture it before our normal shop air currents blow it all over.

8. The more air a blower impeller pushes, the harder the blower motor works. Trying to move too much air can easily over stress your blower motor. The increased airflow from adding a cartridge filter and larger ducting can potentially burn up a dust collector motor from working too hard trying to move too much air. Cartridge filters have so much surface area that the resistance can fall too low. This can double total airflow. Likewise, moving from smaller to larger ducting can also move so much air we can easily burn up our dust collectors when shifting from 4” to the 6” diameter ducting needed to move enough air at our larger machines for good fine dust collection. I recommend you use an amp meter before and after adding a cartridge to ensure the motor does not draw too much current and burn up. Adding more ducting or a partially closed blast gate before the blower inlet can cure this problem.

9. Not every dust collector can be upgraded by just adding a cartridge. I have not heard of anyone having a problem adding a cartridge filter to 1 hp and smaller dust collectors. I’ve heard that many have successfully added cartridge filters to the 1.5 hp and larger collectors, but almost all have problems. The issue is almost all dust collectors come with a fairly inefficient or just plain no separation ring and poor inlet design. This allows far too many heavier chips and volume of dust to blow up into our cartridge filters. Not only do the chips punch holes, the chips and sawdust gets stuck in the pleats creating a cleaning nightmare. All can be fixed by replacing the bag tree ring with your own separator.

Basics

Just adding a cartridge filter or even a cyclone is not enough. You also have to do a number of other things or your tools will still keep your shop filled with very unhealthy levels of fine dust exposing you and those close to you. To collect the fine unhealthiest dust you also need better tool dust hoods, bigger tool dust ports, larger diameter ducting, and sometimes even better tool designs.

1. The size of blower to move at least 800 CFM at our larger machines depends upon the overhead. Overhead in a dust collection system is resistance measured as static pressure. When using minimal resistance filters and little to no ducting and no separator, it takes at least a 1.5 hp dust collector motor turning at least an 11.5” diameter impeller to move enough air. We need at least a 2 hp motor turning a 12” impeller if you add enough ducting for a two-car garage sized shop. Add the additional overhead of a cyclone with that ducting and we need a real 2.5 hp motor turning at least a 13” diameter impeller, but most find it better to have the additional capacity of a full 3 hp motor turning a 14” impeller. You can get by with smaller units only if you either use a bigger impeller, a more efficient impeller, or increase the motor speed well beyond the normal impeller 3450 rotations per minute speed.

2. Almost all available inexpensive hobbyist dust collection ducting, fittings, and ports on our machines are too small. The standard 2.5” vacuum hose and 4” diameter hobbyist dust collection hose, duct, and fittings work well to collect chips, but are near worthless for collecting fine dust. If you had to change your garden hoses all over to 1/8th inch tubing, you would not be very happy with the result because that tiny pipe would all but kill the water flow. The same is true with airflow. The amount of air moved like water depends upon pressure and the pipe size. When moved at the up to 12” of pressure typical for hobbyist blowers, maximum air volume in a 3” diameter pipe is about 250 CFM, in a 4” pipe about 400 CFM and about 600 CFM in a 5” diameter pipe. It takes roughly a 5 hp motor turning a 16” diameter impeller to move the same amount of air through a 4” pipe that a 1.5 hp motor turning an 11” impeller can easily move through a 6” pipe. Picking pipe with the smoothest interior helps some, but not that much. With the pressures available from hobbyist blowers we need 6” diameter duct to move the 800 CFM that the air engineers have proven is the minimum to get good fine dust collection at our larger tools. Unfortunately this becomes an expensive nightmare as 6” pipe and fittings can cost ten times that of the competitive pricing for hobbyist ducting.

3. The classic ducting design that works well for chip collection hardly works at all for hobbyist fine dust collection. Traditional dust collection system designs use down drops that are smaller than their main. These 3”, 4”, and 5” down drops make no difference in commercial systems because almost all of the ducts are open at once and there is plenty of airflow. This is not the case with hobbyist systems that normally only have one duct open at a time. A length of smaller duct will in about ten diameters reduce the volume to the maximum that sized pipe can support at the available pressure. This causes no problems in vertical runs because the airflow speeds up in that smaller pipe. However, when the air gets back to the main with only that single small pipe feeding the main, the airflow in the main slows badly. A main that supports an optimized 4000 feet per minute (FPM) duct speed will drop to 2100 FPM after about a 4’ length of 4” duct. When the main air velocity drops below 3000 feet per minute (FPM) we build little dust piles in the mains that pose a serious fire hazard and can damage our equipment. These piles constrict the airflow until the air speed builds amply to get by. That keeps the pile from growing taller, but it just keeps growing longer and longer. Any spark from say cutting a nail or staple ends up with a potentially serious problem because the high airflow acts like a bellows fanning that spark into a potentially major problem. When you open a larger gate downstream then all the piles go slamming down the line. They get so large they will shoot through a separator and hit the impeller so hard they over time can ruin motor bearings, cause plastic and aluminum impellers to fail, and then ruin filters with holes, plugging, and reduced filter life.

Fix Your Tools

Economics have turned most hobbyist woodworking tools into copies of older professional woodworking tools that are now made in third world countries. Most of these older tools either had no dust collection or at best limited chip collection. To successfully collect fine dust from these tools they mostly require some modifications to control fine dust as it is made and permit moving enough air to capture that dust. You must also do your homework followed by making needed changes to your tools.

1. We also mostly only have 4” dust collection connections known as ports on our tools. Convincing ourselves to voluntary tear up our expensive tools to replace the too small tool small dust ports with the bigger ports we need is not fun or easy to do.

2. Likewise, we must also replace or change our tool hoods to control and allow capturing the fine dust at the source, or we are wasting our time and money.

Suggested Solutions

Hopefully at this point you are comfortable that we must upgrade our hoods and use all 6” ducting or we are not going to control the fine dust and move enough air to capture it. We also need a big enough blower to overcome the resistance of our filters and ducting. It takes a blower that will move a real 1100 CFM maximum to provide ample airflow with no ducting. It takes a blower able to generate a real 1200 CFM maximum to power the ducting for a small shop. For most hobbyist sized shops it takes a blower able to move a maximum of 1900 CFM or more to power the additional ducting. Providing less than this much blower will only end up in compromise solutions that do not move enough air to capture the fine dust at the source. Likewise, we either need to keep our dust collector outside and not return the air to our shop, or we need to provide at least 0.5-micron filters and preferably 0.3-micron filters for better protection. Here is my list of potential solutions for collecting the fine dust at the source and getting rid of it in order of effectiveness along with comments.

Good Solutions

1. I believe the best approach is to build an efficient cyclone and use ample 0.2 or 0.5-micron filters. This is the only solution that will not quickly plug our fine filters killing needed airflow and quickly wearing out the fine filters. Only my cyclone design, Clear Vue Cyclones, and the WoodSucker II meet these requirements. All other hobbyist cyclones use a combination of inefficient cyclone separation designs, too small of blowers, and too open filters.

2. The next best approach is to use a 1900 CFM or better dust collector placed outside without returning any of the air inside. This presumes you have no gas, wood, or coal fired appliances in your shop that could fill it with deadly carbon monoxide and that you do not have a problem sending all your conditioned air outside.

3. The next best approach is to use an existing dust collector replacing any old 30 micron bags with fine filter bags, build an airtight enclosure for your bag tree, and then come off of that enclosure with a fine cartridge filter. If you do not go with the finer bags that permit more airflow, this approach will kill your airflow. Don’t forget to make your enclosure with a door that will let you beat the upper bag and empty the lower. For this to be effective in moving enough air to capture the fine dust you need a 1200 CFM rated dust collector that you move between machines with no ducting except a short length of 6” flex hose. To use this solution with ducting you need a 1900 CFM or larger dust collector. I find this solution better than just adding a fine filter because the dust collector bags keep most of the stuff out of the fine filters greatly extending their life and amount of airflow between cleanings.

   

Lesser Solutions

1. The next best approach is to convert your older dust collector to a cartridge filter. The problems with this approach is many early and less expensive dust collectors do not move enough air and they do not have a usable separation ring, so the filters will get plugged and ruined quickly. The best conversion is to follow my directions below with a large surface area fine filter using a fine screen to keep the larger chips from plugging the filter and punching holes in it. Replacing the original bags with a top quality cartridge filter from the various hobbyist vendors made for these conversions works, but all of the existing conversion cartridges and new hobbyist units are only offering 2-micron or worse filtering. With the worst health damage caused by 2.5-micron and smaller sized particles, these don’t offer much protection. That’s why I recommend using certified 0.5-micron or better yet 0.2-micron cartridge filters. With my support Wynn Environmental developed a new 0.5-micron wide pleated filter designed to mount right on most 1.5 hp to 2 hp dust collectors. They make this filter in the same paper poly blend that most other makers offer, and offer it in the far superior all poly version. Take a look at their solution by clicking here!

   

Cartridge Filter Installation

1. Now that these units have been out for a while, we have learned quite a bit about their strengths and weaknesses. Cartridge filters can provide better respiratory protection than bag type dust collectors, but each also shares some problems. Even with filters prepared with a dust “release agent” the increased airflow of these more open filters with far more surface area carries chips and dust into the filter leaving the pleats plugged. And, this increased airflow also causes some of the larger chips to hit the filter so hard they jam in place and can make holes that quickly ruin a filter. Cleaning the fine dust can be done with a vacuum or compressed air. CAUTION! When using compressed air to clean a cartridge do not go over 60 PSI or you will blow your filter apart! Unfortunately, neither compressed air or a vacuum do much good at getting the larger chips loose from the filters. These chips often require cleaning by hand.

2. Although you can either buy a pricey cartridge filter kit to convert an existing dust collector, it is less expensive to do your own conversion. I initially shared a wide-pleated conversion. It works about the same as the commercial cartridge collectors suffering from the same clogging problems. To address that clogging I added a simple piece of window screen. It worked so well, I tried that screen with a finer filter. It worked even better. Now instead of recommending a wide pleated cartridge coated with a release agent, I now recommend use of a fine pleated cartridge filter protected with a screen. The Wynn and Farr compatible fine pleated filters I recommend provides real 0.5-micron filtering instead of the roughly 2-micron offered by the wider pleated filters. These have at least triple the area of the wide pleated filters that generally run under 100 square feet in area. This larger surface area greatly improves airflow, reduces filter resistance, and lets us go much longer between cleanings. We can also use the same filters that we use with our cyclones allowing us to later upgrade to a cyclone without having to buy new filters.

3. Even these fine filters are not ideal as much of the finer dust will go up and stick to the filter. Still, unlike the wider pleated filters, the chips cannot hit the pleats and as soon as you turn the motor off and give the filter a tap or two, the majority of the dust will fall.

4. There are many types of fine pleated filters used in dust collection. Sadly, most of the larger filter suppliers such as Farr Filter USA Dealers apparently will not do business with hobbyists. I recommend and buy my cartridge filters from Wynn Environmental because they have good filters, like working with hobbyists and have good prices. They also carry good inexpensive 6” flex hose.
   
   I started using and recommended a pair of the Torit compatible cartridge filters (2A226BLFROL) that have about 224 square feet of filter area and come in a 12.75" diameter 26" tall unit. We can also buy these same sized cartridges in a more expensive washable polyester material. These come in 100 square foot units (#2A100SBOL), 140 square foot (28A140SBOL), and 202 square foot (29A202SBOL). Although pricey, these washable filters can be cleaned with compressed air like a paper/poly-blended cartridge. Then when that stops working, instead of having to replace the filter, they can be washed with a light soap and water giving it a total life of three to four times the less expensive units. These washable cartridges are what I recommended before discovering how to use the finer filters.
   
   Today, I prefer the Wynn and Farr filters. The Wynn information is on their conversion page mentioned above. The Farr is Part# 125154-005 compatible 300 square foot filter that is 99.4% efficiency at 0.5 microns when moving 1000 CFM. It is 12.75" in diameter by 34" long. I buy these as the Wynn compatible Farr filters (9E300BLFR). If you have the ceiling height, using two of these works better, but you should also get one with both ends open (9L300BL). Make sure you ask for the filter with the external metal grid, not the internal as I got as mine is much harder to clean! Talk to Wynn Environmental for the one best for you. In this case bigger is better! (Thanks Jack Diemer for introducing me to Wynn Environmental and Dick Bryan Polinski for pointing out the larger sizes!)

   Note that I also recommend the fire retardant filters and filters coated with a release agent. Make sure you have both before buying.

5. We would get a little better performance by making a filter canister that sits on top of our dust collectors to hold the filter. A canister would push the air through the filter the way it was designed to work from the outside to the center and let us clean by vacuuming the filter outside. I don’t bother because making a canister is much more work for little gain.

6. Regardless of which you decide to go with, make sure you let Wynn know what you will be using it for so they don't send you a fine filter for the cyclone as that will not work!

7. Required Parts: Torit style filter, threaded rod, matching threaded knob, fine metal screen, two nuts, two lock washers, and a small cross bar.
   or
   Farr style filter with wood doughnut, fine metal screen, and four bolts with t-nuts in the wood doughnut.
   
   

   

8. Construction: The filters from Wynn Environmental, are near ideal as they are wide enough and have a seal that sits right on the donut shaped plate in the center of most dust collector bag trees without having to make a board or anything. To hold it in place, slip the rod through the sealed top hole and tighten up against the cross bar from the above picture. The cross bar needs to be as short as possible and still span the opening. Making it sit in the circling air stream will cause lots of turbulence and seriously degrade separation causing far more material to go up into your filter. Add your lower plastic bags and your modification is complete.

   

9. Anyhow, at this point a few people had trouble with converting over their Delta 1.5 hp and Grizzly 1029 dust collectors. They work fine except when planning and joining. Joiners and planers create a heavy load of large sail like chips that end up jamming into the pleats causing a cleaning problem.
   
   It turns out that you can greatly improve the performance of these units with three fixes (thanks to Bryan Danner):

   1. If your dust collector does not have a separator ring, you need to add one. It should be tapered so the dust falls down into the bottom bag. The hole diameter should be 1/2 the diameter of your round bag tree assembly.

   2. Shorten the mounting bracket. Rather then simply crosscutting the board, miter cut it so that it's bottom edge extends into the air stream as little as possible.

   3. Mount a cleaning paddle to the threaded rod running down the center of the cartridge. It's 7 or so inches in diameter, extends the entire length of the filter, but does NOT touch the filter itself. It's made out of 1/4 inch plywood. If you get a plug, simply turn the threaded rod, and the paddle breaks the clog up and it drops into the lower bag.

   4. Install a neutral vane.
      
      

      


Disclaimer

The drawings, procedures and words shared on these pages are for information only. Your actions are your responsibility - VERIFY and CHECK information out before proceeding, and don't attempt anything without the required skills. Although I've taken every care to ensure what I have done and presented is safe, dust collection equipment uses electrical components and blowers that when improperly built, used, or maintained may cause serious injury or even death, so USE THIS INFORMATION AT YOUR OWN RISK! At the same time, unless you as a woodworker provide appropriate protections for the fine wood dust you make, you put your health, the health of those close to you, and even the health of your pets at risk. Long term exposure to fine wood dust eventually harms most woodworkers. Please take the time to protect yourself and those close to you. HIRE A PROFESSIONAL ENGINEER to design, specify, test, and certify performance of any dust collection system if you have a commercial or an industrial application, allergies, other medical problems, people working for you, a large shop, work with hazardous materials, or are subject to regulatory oversight. Neither I (Bill Pentz) nor any other references or links on these pages will accept any liability for any damages or injury caused to people or property from the using of this information or from any associated links. No claims are expressed or implied as to the safety, usefulness, or accuracy of this information.