A hp single stage collector carried from machine to machine will do essentially nothing for your lungs unless it has a massive fine filter or blows outside that won't clog too quickly.
It will extend the life of your dustpan and broom, though. They both do suck, but a shop vac is designed for low volume at high static pressures -- it creates vacuum pretty readily and is happy to do so. A dust collector is designed for high volume at fairly low static pressure.
This means a shop vac won't pull a lot of air, but it'll do better with duct restrictions and such. It can handle that all day long, and you can go pretty far i have 25' of shop vac hose and it still sucks fine at the other end.
But if you up that to 4", it pretty much is worthless - the larger duct allows the airspeed to fall so low that it really doesn't move a lot of material. Shopvacs seem to thrive on a little static pressure. On the other hand, dust collectors move large volumes of air but don't handle duct restrictions as well. This is why horsepower DOES come into play, but not nearly as much as impeller design. The impeller sets the ceiling and no additional horsepower will help you overcome duct restrictions called static pressure.
This means that the two kind of go hand-in-hand. It takes a good bit of force to move a large volume of air. Best example i can think of is to try carrying a sheet of plywood outside.
If it's calm, just feel the force it takes to spin the sheet. That is stationary air being forced out of the way by the plywood surface. It takes a pretty good bit of force to move all that air not even very fast. On the other hand, take a small scrap of plywood, maybe 1' square and swing it around -- you can feel the air, but it's a whole lot easier to move faster.
That's basically the difference between a shop vac and a dust collector. It takes a big beefy collector to handle the kinds of static pressure that a shop vac can handle. All of this is to say: you won't replace your shop vac with a dust collector. The two work together in most shops for a strategy of capturing dust where each machine does the best job.
On small handheld tools like sanders and such, a shopvac works great because the access is small and they do better with this restricted pathway. If you put a sander on a big dust collector usually you'll get hardly any airflow and dust collection will be bad you won't burn up the DC, though, contrary to some intuition at first. Sorry, this is a big subject - and there is no "Just do this Set your goals first. Then look at the costs to meet those goals. Then readjust your goals lol to align with the budget you have in mind :P.
Join Date Feb Posts 2, You'll never complain about going bigger than you need. Other than from an operational cost standpoint I'm trying to figure out how I want to setup dust collection in a new shop currently. A couple of 15hp single stage in a dog house, a 25hp single stage in a doghouse, or a 30 ish hp cyclone sitting outside.
Too many options, all of which cost too much. There isn't much on the used market for medium sized stuff either. Yeah, I understand that this is a big's subject and a broad topic. Right now, all I have is a shop vac, so that's what I use. I just slapped reducers on everything and did what I could. On my table saw, I can hear it pulling air but I can't feel it. It pulls in some of the sawdust but not very much. Cleaning our filters also opens the pores quickly wearing them out. We can wear them even more quickly if we use vacuum cleaners or compressors that generate so much pressure they tear open the filter pores;.
It takes months for airborne fine dust to blow away and break down. During this time molds, mildews, yeasts, and fungi turn this dust into ever smaller particles and add additional toxins;. Regulated large commercial woodworking facilities blow most of their finest unhealthiest dust away outside.
They have little choice because fire and building codes require them to put their dust collection systems outside or obtain special equipment certified to be fire and explosion proof. Small shop woodworkers have no such standards and our vendors mostly sell us dust collection equipment that should go outside just like the commercial stuff, but is only made for indoor use. Our trapping the finest unhealthiest dust inside allows it to grow to levels in even minimally used shops that far exceed the levels shown my medical research will make almost all develop health problems, some serious.
Almost any airflow from our tools, dust collection equipment and air compressors will launch this previously made dust airborne. Once airborne, it takes hours for the fine dust to settle. Meanwhile it quickly spreads getting carried in any shared air and on our skin, clothes, and hair into our homes, offices, and vehicles to also expose all close to us to significant fine dust.
To work without wearing a mask all the time we need to collect the dust at its source before it escapes then get rid of the dust. Although this tells us what we have to do, it does not tell us how to get that job done when almost none of the existing hobbyist tools, dust collectors, cyclones, ducting, ducting designs, and filters will do the job providing good fine dust protection.
Until such time as government oversight requires hobbyist vendors to provide equipment that meets industrial standards, we are on our own. This means the only way to get good fine dust with hobbyist equipment today is to take responsibility for our own system and deal with the following challenges. My doctor started off my research on dust collection.
He said most of our tools use older designs that need considerable modification to keep from spraying fine dust all over. When that fine dust escapes, it becomes near impossible to capture and it takes many hours for typical air cleaners and exhaust fans to bring the dust levels down safe enough to remove our masks.
He said air engineers long ago learned they had to modify our tools, often very extensively to protect, control and capture the fine dust at the source right as it is made at each tool. They also learned they had to move far more air to capture this fine dust with our older tool designs than is required to just capture the heavier sawdust and chips.
Unfortunately, most hobbyist dust collectors move less than half the air needed for good fine dust collection. Worse, in spite of inflated advertising claims most hobbyist dust collector, cyclone, shop vacuum, and even air cleaner filters freely pass most of the finest unhealthiest dust right through turning these units into what my doctor calls "dust pumps".
The finer hobbyist filters clean up the way our shops look creating a false sense of security because they also mostly pass the finest unhealthiest dust right through. This near invisible dust gets trapped in our shops where it build to incredibly unhealthy levels.
Almost any air movement from our dust collection equipment, tools and air compressors launches this finest dust back airborne.
Over many years of too much exposure to this finest dust most develop health problems, many serious. He believes the fine filters on dust collector, cyclone, and air cleaner were so bad they led to my being hospitalized with fine dust related health problems.
He said I would have been better off without any of those units as they just stirred up and kept the fine most dangerous dust airborne and trapped inside my shop. He also said forget relying on vendor help, we each must do the work ourselves to assemble ample protections to minimize the fine dust exposures. Not really believing that my owning and using the very best in cyclone and air cleaner put me in the hospital, I had my shop tested and the results scared me into getting serious about learning about fine dust collection see my Introduction.
He shared the health risks of wood dust exposure and gave me a list of immediate to dos see "Health Risks and Doc's Orders" , and pointed me in some directions to start my research.
I immediately took care of the small stuff he suggested then got busy. My research quickly verified my doctor's comment that fixing my dust collection would be a challenge!
Almost all of the available hobbyist information was contradictory, with much of this information just plain bad. Most small shop woodworkers depend upon many sources for their information and all often give bad dust collection information. Most woodworking is a relatively private hobby, so much of our information comes from books and more recently videos and the Internet.
Almost all of that information was produced well before the awareness that fine wood dust is so dangerous. As a result, most tables, tests, product comparisons, magazine ratings, on and on are based on chip collection, not fine dust collection.
Sadly, the magazine and book editors trust their authors, expert testers, and technical staff to do homework that mostly does not get done. At least three of the most popular magazines have recently shared dust collection articles recommending use of HVAC pipe to make complex ducting solutions with multiple down drop sizes.
These are chip collector solutions at least ten years out of date from being dust collectors. Worse, in the last few years there have been at least three major magazine articles rating dust collectors and cyclones. Each sited vendor flagrantly exaggerated maximum airflow and filtering claims without verifying.
Worse, the dust collector test allowed one winning vendor to supply a test unit with an oversized impeller larger than they ship on that model tested. That makes for great performance but will quickly burn up a motor. That same test killed the performance on the best dust collectors by choking their airflow with too small a test pipe. This same magazine then did the same in reverse on their cyclone tests. They used oversized pipe to give marginal performing units good tests and normal sized test pipe leaving the best performers looking bad.
I decided to never rely upon magazine testing for their information when those magazines depend upon the same vendors advertising for their livelihoods;. Many small shop woodworkers rely upon their intuition and experiences with a lifetime of using vacuum cleaners to configure their dust collection systems. Most of us think about our dust collectors as a giant powerful vacuum cleaner that will pull air around obstructions, through small openings, and through small pipes.
A real vacuum operates at the pressures to do just this. At typical dust collection pressures air will hardly compress at all, so we need to think about airflow being far more like water. Any tiny pipe or obstruction such as a partially open valve will kill flow;.
Many also rely upon communications with their friends, whether through the Internet or in person. Even "old salts" meaning long time woodworkers don't have a clue as to what is really needed for fine dust collection without doing a bunch of homework.
I have to admit giving bad advice myself for far too many years before this whole fine dust issue reached up and bit me in the tail hard. Although this advice from friends is often sincere and meant well, it just cannot be trusted; and,. Finally, a few of us are fortunate enough to go to classes and teaching centers, then share our experiences. As wonderful as those experiences often are, frequently the fine dust collection there is either missing or terrible.
That leaves a strong false impression that there really is no concern. With no government oversight and uninformed buyers, hobbyist vendors have long sold "chip collectors" that do a great job gathering chips, but do little to protect our health from fine dust. In the late eighties commercial woodworking concerns had to make change to meet government air quality standards, but our hobbyist market failed to follow.
Hobbyist vendors continued to push out low cost Pacific Rim imported copies of older tools known to be terrible dust generators. Enough direct sales firms market these mostly copied "tools by the pound" to make the competition for entry-level small shop woodworker business beyond fierce. To stay competitive many firms engage in an ugly advertising war. With almost no oversight, many claim whatever they want.
Sadly, even with oversight, our "truth in advertising" laws provide no protection letting vendors legally claim anything they can demonstrate. With the appropriate "tricks" and testing, unscrupulous vendors bombard small shop owners with useless "maximum" performance claims.
Credible vendors find themselves forced to either similarly compete or watch their market share rapidly decline in favor of supposedly better performing lower cost products. Here are a few of the techniques that vendors use to make their outrageous claims. Blowers configured with special hyperbolic inlets and with no filters or ducting move just about double the air that they move under real working conditions.
Vendors advertise these maximums forgetting to tell their customers that the performance is a curve with real maximum in use performance about half the advertised volume. As a result most hobbyist dust collectors, cyclones, vacuums, and air filters provide less than half the advertised airflow and nowhere near the airflow needed for good fine dust protection;. Motors for an instant while starting draw four or more times their maximum working amperage.
By measuring this highest amperage and converting it to horsepower a vendor can advertise a real 1. Standard amp volt household circuits will safely run up to a real 1. With a circuit breaker upgrade of these circuits can run a real 2 hp motor, but most recommend instead using volts for this sized motor and larger. Only those who buy from reputable vendors are going to get home with a motor that actually delivers its promised advertised horsepower;.
Filters can simply build up enough dust cake to prove any level of filtering desired as long as they don't also have to pass any air. The key is never follow standard engineering practices and say what airflow comes with any level of filtering.
Sadly, with far too little filter area many hobbyist filters in our dust collectors, vacuums, and even air cleaners quickly clog and stop moving the air we need for good protection. Even with clean filters, at working airflow levels many hobbyist filters pass dust twenty to thirty times larger than advertised turning our blowers and air cleaners into dust pumps that recirculate these unhealthy fine particles;. Tools are often advertised and come with ports and such that make them look like they have good fine dust collection built in.
When we get these tools home they instead blast dust everywhere. Sadly, any dust port or dust bag added to a tool lets the seller legally advertise the tool as having dust collection built in.
Few vendors mind stretching that fiction further by also saying their tool has good fine dust collection built in. With no standards or legal requirements many tools are designed with just enough dust collection to make the claim without actually working.
Using the rules by which this industry operates, advertising claims are about as useful as my telling you that my car for sale gets 92 miles per gallon. Moreover, I can prove it coasting down a mountain and reading the MPG gauge.
Shoot, I can even sell you an old clunker saying it has a brand new motor and tires by buying a new electric toy car with new tires and tossing it in the glove box.
Although perhaps provable, the information provided fails to give the facts needed to make an informed decision. I learned that we need to capture the fine dust at its source and get rid of it , but our hobbyist tools and dust collection equipment does not do either well. Our tools often have tiny dust ports far too small for our dust collectors and often even too small for our vacuums.
Our tools mostly lack designs and hoods that will control the fine dust before it is captured so spray fine dust everywhere driven by the air from our blades, bits, cutters, belts, motor cooling fans, etc. We need to replace our tools with ones that control that dust or modify our existing tools with hoods, ports, etc. Add hobbyist dust collectors and cyclones that only provide half as much airflow needed to collect the fine dust, plus filters that pass most of the fine dust right through and hobbyist dust collection is a dangerous mess that is hurting people.
Finally, most hobbyist woodworking stores and tool vendors reinforce these poor ducting designs by mostly only carrying inappropriate ducting and dust collection equipment.
They mostly only sell 4" diameter sized ducting with sharp ninety-degree bends, Ts, and very rough interior walled flexible hose. This stuff does fine job keeping the shop floor clean and looks sharp, but it cannot move enough air to capture most of the fine dust from our larger machines.
With the pressures available from most hobbyist sized blowers anything less than 6" hoses, flex hose, duct, fittings, and ports will choke the airflow quickly below the CFM we need. Far more information is available on my Equipment and Ducting pages. Dust collection manufacturers provide dust collection design firms with both Air Volume Requirements tables and Airspeed Requirements tables so these firms can design commercial air systems that will carry materials without plugging or building up piles in the ducting.
Air engineers who work for these manufacturers have done considerable work as have many of the universities to build careful tables that show just how much air needs to be moved and at what speed for each different type of material.
For wood dust and chips, careful testing shows airspeed of between to FPM is needed to pull in the chips and heavier sawdust from our machine hoods. We then need about FPM to keep our horizontal ducting runs clear and about FPM to keep our vertical ducting runs from plugging. Wanting to ensure good dust collection without buying and paying for running too large of a blower, most air engineers recommend we design our dust collection systems to maintain a duct speed of FPM in our mains to keep our ducting clear and keep the chips and sawdust entrained, meaning airborne.
This FPM has become an industry standard that is well tested and proven solidly to work to move the dust, but it does not collect the dust. We also need to know how big of a volume of air is needed to be moved at each machine to collect the dust. We can then measure the area of each machine that needs collection, convert to square feet and then multiply by FPM to get the required CFM.
This theory approach works fairly well and shows most large hobbyist stationary tools need between to CFM of air volume for good chip collection. Verifying these calculations with testing is expensive and takes lots of work. We need to test each different type and size of woodworking machine working a variety of materials. Fortunately, almost all of this work was done for us and published ages ago. Since larger hobbyist vendor tools are the same as smaller commercial tools, we can use these same test results.
Good chip collection on almost all hobbyist larger stationary tools requires between to CFM just as calculated. To comply with government standards to also provide good fine dust collection, these same large equipment vendors and university staff went back to work. Their testing showed that airspeed of at least 50 FPM effectively moves airborne dust.
This makes sense because we all know from watching dust particles in a beam of sunlight that it takes very little air to move the airborne particles. With tools designed and built from the ground up to protect and control that fine dust for collection, the prior "chip collection" air volumes work well.
Festool and a few other brands have shown with their special tools engineered from the ground up with good fine dust collection built in that totally controls the airflow around where the wood is being machined actually get good fine dust collection with an oversized shop vacuum.
Unfortunately, most of us use tools with minimal or no "chip collection" built in. Our tools and their open cutting areas allow the airstreams from our blades, bits, cutters, belts, motors, etc.
Almost all air engineers say the only way to provide good fine dust collection for most hobbyist and older tool designs requires us to replace the hoods, sometimes remake the tools and provide nearly double the air volume to collect the finest dust as it did to collect the heavier chips and sawdust.
The calculations show the same thing because collecting the finest dust at most current tool designs requires delivering our airflow over a much larger area than just at the port at the end of a hood. Both the math and testing show we need to provide close to CFM air volume movement to get good fine dust collection. At first these larger air volumes do not make sense because we know it takes 50 FPM to move the fine dust and FPM to move the heavier sawdust and chips.
We already know from experience why it takes more air. When we use our shop vacuums they only pickup up right next to the end of the hose. The reason is unlike blown air that holds together for quite a distance, air being pulled or sucked by a vacuum comes from all directions at once.
This means that the area being pulled from is roughly a sphere. It also means that our airspeed will fall off at roughly the same rate as that sphere area grows. Most air engineers target for a duct speed of roughly FPM because this is what we need to pickup most woodworking dust and keep our vertical ducts from plugging. We can then divide those airflows by 50 FPM to see how big of an area each will cover, translate into square inches then convert to the surface of a sphere. Although the math is fun, the bottom line is airspeed drops below the 50 FPM we need for good fine dust collection very quickly.
Our 2. This explains why we see almost no pickup just 2" inches from the end of our vacuum hoses. Many round this to 9" and use this as the standard for 4" duct. In short we need to move a lot of air to ensure capturing the fine dust.
This unfortunately creates some controversy that is very important to small shop woodworkers. One group of hobbyist vendors would like for us to believe that we can get great fine dust collection by just fixing our tools to control and protect that fine dust. Air engineering testing shows that even with the best recommended changes, we really do have to move this additional air if we are going to have successful fine dust collection.
Otherwise, we remain stuck with good "chip collection". I believe as we move toward the far more stringent medical air quality standards already adopted by the European community, the only way for commercial firms to meet these standards will be to buy new tools with good fine dust collection built in. Meanwhile, I continue to agree with and support the standards from those who want to replace the hoods and move more air because my pocketbook is not up to replacing my tools.
Frankly, the price of the newer tools with dust collection built in remains so ridiculously high they have not yet earned my interest. It takes a lot of work on our part to get good fine dust collection with our current tools.
Each of us must modify our tools to keep the fine dust protected from being blown away, controlled until it can be captured and then directed for delivery right into our dust collection hoods. We also must use a blower large enough to ensure moving ample air at our tools. The following CFM requirements table gives the airflows required at each size and type of stationary woodworking tool to meet different dust collection standards. These tables are not provided by the standards organizations, but instead like tool hood designs are closely guarded industry secrets as the hood designs and these table values are what permit a professional dust collection firm to ensure their systems will meet a particular standard.
When I built these web pages our small shop vendors were throwing a wide range of numbers around with little to no clue as to what those numbers meant and they badly confused the different airflows needed to provide good fine dust collection. Specifically, the top magazine rated small shop dust collector provider who continues to pretend an authority role in dust collection which is not borne out by either their information or actual performance of their products said the CFM numbers to meet "chip collection" standards were more than enough to pull in the fine dust.
They assumed without checking their facts that because it takes so little airflow to move airborne dust, that the much higher airspeeds required for "chip collection" were more than ample to also pull in the fine dust. They were dead wrong, but so few knew anything about dust collection that we ended up with most of the magazines and even the two books on small shop dust collection following that same wrong lead leaving a mess today where most end up confused.
For what it is worth, after reading over my web pages that same firm now has copied my information without permission and sadly has had the audacity to blame me for creating some of this confusion that they caused.
American Air Filter AAF was one of the leading firms who built fine dust collection systems and filters to meet government air quality requirements. They were kind enough to allow me to share their proprietary airflow tables to counter some of the massive confusion over airflow requirements for small shop woodworkers. Remember this below table is useless unless you start by upgrading your hoods. The above CFM requirements table only provides the airflow required for good fine dust collection at our larger stationary tools.
This table intentionally does not address the airflow needed to capture the fine dust at smaller and hand held tools. There is a huge difference in collection requirements for smaller tools. Getting good fine dust collection on our hand held tools is often a matter of using good judgment. If your smaller tools spray fine dust all over like my electric and air powered sanders, then you need to provide better dust controls and often move far more air to capture the fine dust particles.
The only way to get good fine dust from some of my hand and stationary power tools with built in tiny ports, is to use a vacuum hooked to the small port plus dust collector hooked to a portable hood that draws the air from right next to the where working. Often I also need to use my downdraft table with sideboards up. Whenever I find myself needing the downdraft table to control fine dust, I try to put on my mask and work outside , or wear my mask with the exhaust fan running, then leave when done work and stay away until the air clears!
If you look closely at this table, you will see that we really need about CFM at most of our larger stationary tools to get good "chip collection", meaning picking up the same sawdust and chips that we would otherwise sweep up with a broom. The European Union has already adopted this medical recommendation as its own standard and it is what I recommend for most small shop woodworkers. CFM Caution Please realize that this table shows the airflows needed for the different levels of collection for larger tools.
For smaller shop tools with smaller ports we often need far less airflow, but at much higher pressures than can be delivered by dust collection systems.
For these smaller tools we often need a powerful shop vacuum with fine filter, sometimes a down draft table, and often a portable hood connected to our main dust collection that we can move to where we are making sawdust and chips.
You also should notice from this table than many tools such as the table saw requirements are given with upper and lower pickup requirements. If you don't use two pickup hoods on your same tools as shown in this table, you need to follow the song's advice and change your evil ways! Moving enough air is not enough. To capture the fine dust at the source the air engineering firms who deliver systems guaranteed to meet air quality standards found most tool hoods need upgraded.
The tips of our saw blades and cutters are launching dust at over miles per hour and a typical dust collection system has the air moving at less than sixty miles an hour. This difference in speed means if we don't have hoods that either catch the dust or block it from getting launched it will escape. CFM Experiment At this point many are not quite ready to believe that we need to move more air volume to collect the finest dust. Here is a simple game experiment to help you be more comfortable.
Airflow requirements for good dust collection seem a paradox. It takes very little airflow to move really fine dust, yet we need far more airflow to capture that same fine dust than we need to pick up the same dust we get with a broom. To make sense of this on my other pages I share a simple game that tries to use air and two straws to move a balloon. One person is only allowed to blow and the other to only suck. The one who blows always wins because they move a directed stream of air that can push that balloon all over.
That directed stream of air goes quite a distance before friction will slow down the air. Sucking pulls air from all directions, so airspeed drops off at the same rate as the area of a sphere. That formula is 4 times pi times the radius squared, so it takes moving a huge volume of air make any effect even a tiny distance away. Most of us already know this from using our shop vacuums that will only vacuum up right next to the hose nozzle, but on blow will send dust everywhere. The same thing happens with our fine dust collection.
In addition to the low cost, PVC is available at most home centers. And as you can see in the photos below, elbows, Y-fittings, and connectors can be used with straight pipe to build a complete collection system. The key to putting together a PVC system is a special adapter from Rockler to make the initial connection to the collector.
After that, it's easy to build just about any configuration. One concern about using PVC is the possibility of static electricity building up and causing a spark in your collector.
Studies suggest this is highly unlikely to happen with dust collectors in a home shop. To alleviate any fears, you can always use copper wire to ground the ducts. In fact, grounding kits, like the one shown above, are available for this very purpose.
You'll find grounding the system helps prevent annoying shocks as well. No matter which type of material you choose, adding ducting isn't difficult.
But it does require a good plan before you begin. And the planning process might make you rethink the way you lay out the tools in your shop. You'll find any collection system works best when you keep the duct runs as short as possible. A good place to start is to make a scale drawing of your shop and tools to experiment with different layouts. The drawing above is a good example.
Try to keep the biggest dust producers closest to the collector and add a blast gate for each tool. To channel your dust collector's airflow from a particular tool, you need to be able to close off the unused portions of the network. The easiest way to do this is to incorporate blast gates photo below into the design. Blast gates are simply sliding doors that fit between two sections of pipe.
By closing the door, you reduce the airflow in the network, focusing it on an open gate. I find it's best to place a gate on each stationary tool, positioning it for easy accessibility. Sometimes this means placing it on a branch in the duct work, as shown above. But there are times when it pays to have the gate right at the tool's dust port for convenience and ease of use.
A gradual bend is also less likely to get clogged with debris. The photo below shows you what I mean. No matter how careful you are about laying out and installing the ductwork, there are still things that can cause it to lose some of its collection power over time. Fortunately, most of these can be prevented with simple checks and maintenance. For example, any blockages in the ductwork will cause a severe restriction. That's why I leave a few connections with only a friction fit and no glue.
Start by determining what the maximum airflow through the system will be. To do this, list the tools that you'll connect to the system.
Beside each one, jot down the dust-collection airflow it requires in cubic feet per minute CFM. You can come up with this figure several ways:. The single largest CFM figure on your list represents the maximum airflow your dust-collection system will have to support.
This assumes that airflow from each machine can be shut off with a blast gate. If you will have more than one machine operating at once or if a single blast gate serves more than one machine, add together the figures for those machines to find the maximum flow.
The speed of air movement through a dust-collection system is critical. For systems carrying woodshop dust and chips, engineers recommend minimum air velocity of 4, FPM in branch lines that's about a 45 mph breeze and 3, FPM in the main duct. The speed of the air moving in the system may exceed these figures, but shouldn't fall below them.
Maintaining the velocity at or above the minimum value ensures that dust and chips will remain in suspension as the air flows through the system. Velocity of an airflow depends on duct size.
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