DC Question

[Jeff Cord]

I'm starting to shop for a DC for my shop and have some confusion about the "ratings" (CFM, FPM, etc).
I've got the FWW review from March in front of me but something isn't making sense. I've also read Bill Pentz's web site a couple of times and am still having a hard time following along.
My question relates to static pressure. SP is measured in "inches" (inches of water?)
I understand (I think) that static pressure is like friction in that as the pressure rises the CFM and FPM drop. At a certain point there is so much pressure that the CFM and FPM drop to a point where the DC is no longer doing its job.
Where does the pressure come from? Connectors, hoses, etc. I think I'm OK so far.
So, in order for the DC to work for me I need to be sure I keep the pressure down so that the air flow is high enough.
Now the confusion. Tonight I'm looking in a catalog that lists a DC (cyclone) as having 1900 CFM AND 11.2 (inches I assume) of static pressure. Why does the DC itself have static pressure?
Is this a characteristic of cyclones that non-cyclones don't have?
I'm confused.
jeff

[Kent Fitzgerald]

Yes, SP is measured in inches of water.

If you've read Bill Pentz's pages, you've read about DC performance curves, which show the amount of air (CFM) that a DC can move at a given SP.

When a manufacturer just specs two numbers, they usually represent the extremes of the DC's performance curve: in this case, the DC can move 1900 CFM (at 0" SP), or pull 11.2" of SP (at 0 CFM).

[tod evans]

jeff, you can read and injest information `till you`re blue in the face but all of the advertising gibberish is just that. if you`re wanting a hobby-shop type unit that`ll suck both the clearvue and onida get good reviews here from folks who use `em......02 tod

[Dino Drosas]

Jeff, After going through much of what you describe, I made my decision and bought the ClearVue cyclone. I have just finished installing it using sriral ducting from Penn State and could not be happier with my choice. I have emptied the 30 gal dust container twice and have yet to see even a teaspoon of fine dust at the final filters (this is what really tells the story). I still don't understand all the lingo but after reading Bill Pentz's work I know I made the right choice.

[Jim Becker]

To your original question, "where does the pressure come from": The duct work can only hold so much air at a time and the fan creates a pressure differential which moves said air. As the size of the duct decreases or other "restrictive" features are added, like turns and flex hose, you are making it harder to move air through the system. This increases the pressure differential. At some point, you don't have enough air or can't move enough air at a given velocity to effectively transport chips and dust. This point is generally shown on a graph called a "fan curve" and is the point where the CFM drops below a number, such as 300-350 CFM. The SP listed at that point is the maximum SP for that particular blower/DC combination. CFM below that number just can't move the dust and chips effectively.

A practical example of this is when you hook up a DC to a tool with a very small dust collection port. While it creates a lot of noise, you can't move much air; dust collection is inadequate in most cases. In fact, a shop vac will work better on tools with very small dust ports than a DC system. Shop vacs are designed to operate at very high SP and that is the situation with small ports and small hoses. If your tool has a 4"-6" dust collection port, you can and want to move a lot of air through it to transport the dust and chips. The SP is potentially very low in this case and the big fan of the dust collector can do its job since there is enough air available with little restriction on its movement.

[Bill Pentz]

I believe most already understand much of the basics of dust collection simply from a lifetime of experience with water. At typical dust collection pressures air becomes nearly incompressible, just like water. The amount of water you can move through a garden hose depends upon the hose and the available pressure. At the same pressure a big fire hose will move lots more water than a small garden hose unless the valve is mostly closed. A single point of constriction, in this case a valve will control the flow through the entire hose, so to move maximum air or water we need the hose to not have any small openings which we call ports, no smaller hose meaning duct or flex hose, and no sharp bends or interior pipe roughness. Engineers have long studied all the different ducting components measuring how much resistance each adds. We use a static pressure calculator to total up the resistance of the parts to get a fairly good idea of how much total overhead our system will create.

You then need to use a blower that has ample power to overcome this resistance to be able to move the desired volume of air at the needed duct speed. Blowers sling the air off their blades creating a vacuum. The strength of this vacuum depends upon impeller type, size, and speed. We typically use material handling impellers that are flat plates with blades. The blades are made with heavy metal able to handle hits from small blocks and such. The blades on material handling impellers are also designed to be self cleaning so they do not trap dust or strings that could throw the impeller out of balance and quickly ruin our motor bearings. With our direct drive 3450 RPM motors we typically get blowers that will provide a maximum pressure about six times the motor horsepower. Vacuum cleaners simply put a cap on top of the blades to turn it into what is known as a caged impeller then spin the impeller six to eight times faster creating pressures that are typically about 30 times the motor horsepower.

We measure the “maximum static pressure” a blower can generate by sealing up our duct system tight so there is no air movement. With all sealed and the blower running we connect a tube stuck in water. The “maximum static pressure” is the number of inches that blower pulls the water column up the tube, often abbreviated as W.C. inches This is the maximum possible suction that a blower can produce and defines the available pressure we have to move air. In terms of water this is about the same as how high and big is our storage tank. The taller that tank and more water it holds the higher the available pressure.

This maximum static pressure then needs to be combined with an open duct to measure how much air actually gets moved which we generally measure as cubic feet per minute (CFM). Sadly, “maximum CFM” is a serious problem area with small shop vendors because it is too easy to create test conditions that move a “maximum CFM” that is ridiculous and meaningless except for advertising hype.

To understand why advertised “maximum CFM” becomes pretty much meaningless we need to go back to looking at how our blower is actually sized to meet a specific need. Almost all dust collectors and cyclones use material handling impellers that are near identical except for impeller size. Each size impeller will move a maximum amount of air when there is the least amount of resistance for the air going into the blower and will move less air until hitting “maximum static pressure” when the blower inlet is closed. It takes a certain amount of work measured as horsepower to move any given volume of air, plus the additional horsepower to overcome the resistance that is slowing the air from entering the blower. We plot each blower impeller performance as a “fan curve” that goes from maximum airflow at lowest resistance to minimum airflow at “maximum static pressure”. In addition to needing more horsepower we also need a bigger impeller to generate the additional vacuum to overcome the resistance. Because even a small 1-car garage sized shop with ducting will have a worst case resistance of about 6”, almost all dust collector and cyclone blowers are sized with oversized impellers to address this additional resistance. If you add a typical hobbyist cyclone which takes a lot of power to turn the air in its tight separation spiral, you add up to 3.5” more resistance resulting in needing just over 1 hp larger motor and an impeller that is roughly 2” larger in diameter than a dust collector that would move the same amount of air. So with that long winded explanation, the problem is simple. If a vendor tests their blower without the expected resistance they get huge impressive CFM airflow numbers and will quickly burn out blower motors. Because our heavy duty induction motors can handle a large startup load for a short while, they often can support testing that runs the horsepower to well over double what the motor can sustain without burning out. As both advisor and critic of some of the more recent magazine dust collector and blower testing, I know a lot of blower motors “let the smoke out”, meaning burned up from pulling many times their rated amperage. This is why any “maximum CFM” without knowing the amperage being used at that CFM and the motor’s rated amperage is pretty much meaningless and dangerous. In real use you can figure on only getting about half this “maximum CFM”.

To put this in perspective let’s look at the typical overhead in our shops then what sized motor and blower is needed to overcome this resistance. The ducting and hoods on a typical large stationary tool generates about 2.32” of overhead. Now we add our ducting overhead. Wheeling a portable between machines adds about 1.29” for a typical 6” flex hose and 2.12” for a 4” hose. If we instead use all 6" ducting with smoother walls, etc. our typical 1-car garage sized shop will add a minimum of about 1.69” of resistance, 2-car sized shop about 2.64”, and 3-car garage sized shop about 3.58”. We also need to add the resistance for our filters. Filters start off with minimal resistance when clean and new and that resistance climbs as they “season” meaning build up a thick cake of dust in the pores that does not all come out with normal shaking and cleaning. This caking results in a normal fine bag type filter that comes with most dust collectors and cyclones to have a resistance level that ranges from around 1” to a maximum of about 5”. Although big cartridges can drop this to as low as 0.25”, I choose to use 2.5” because that is average for most of the units we buy. Adding the pieces gives us a total resistance of 6.11” for a small dust collector wheeled between machines, a 1-car garage sized shop with ducting at 6.51”, a the typical average 2-car garage sized shop at 7.46”, and a 3-car garage sized shop at 8.40”. If we use a cyclone or trashcan separator we also need to add that resistance. Figure 3.5” for a typical cyclone and 3” for a cyclone with neutral vane, or about 2.25" for my cyclone design.

Because blower technology is pretty mature, most commercial blowers that turn the same sized impellers at the same speed have near identical performance. This is not true for hobbyists as in all my testing only the Jet and Delta blowers tested with close to commercial airflows, all others tested less, some as little as half due to major design and blower construction errors. Regardless, if we round down to 7” for average sized shops and skip the cyclone or trashcan separator we check a good blower fan table and find our 1.5 hp motor will only move 680 CFM without overloading the motor. Our 2 hp can only move 890 CFM, and our 3 hp can only move 1150 CFM. Adding 3” for a cyclone leaves us with a 1.5 hp motor moving only 570 CFM, yet testing with 1” resistance results in a whopping 1504 CFM pulling 3.56 hp. Likewise, our 2 hp motor at this same 10” resistance level with cyclone added can only move a maximum of about 760 CFM, but when tested with just 1” resistance this same blower moves 1830 CFM drawing a whopping 5.2 hp. Likewise, our 3 hp motor can only move 1005 CFM without over stressing the motor, but when tested with 1” resistance it comes up with a maximum 1984 CFM pulling 6.32 hp. Adding the additional overhead for an average sized shop and maximum filter "seasoning", leaves nothing less than a 3.15 hp motor turning a 14” impeller to move ample air to provide 800 CFM at our larger tools. Since standard motor sizes are 1.5, 2, 3 and 5 hp we can either add a little resistance to make a 3 hp work, use a more efficient cyclone, or step up to a 5 hp motor. I chose to use both a bigger motor and more efficient cyclone because fifteen years of professional air engineering testing shows to get really good fine dust collection we really should move about 1000 CFM at our larger tools and dustier operations. The 800 CFM needed to meet OSHA requirements has already been abandoned due to too many getting ill. ACGIH and the European community recommend far better collection which requires either tools engineered from the ground up to contain and protect the fine dust, or moving more air.

[Jeff Cord]

I am starting to see how I can use the curve in the FWW mag.
I guess the next question is how can I find the curves for other collectors?
I'm trying to be sure I get the collector that gives me enough real performance to capture the dust.

Based on the information in the post above (using the estimates of the SP in small shops) the Delta 760 may be barely sufficient.

Also I'm curious about any opinions regarding the bag used on the Delta 760 (the 1-mil bag) versus the Wynn cartridge?
Is one better than the other at capturing the finer dust?

[Stu Ablett in Tokyo Japan]

I'll not even try to add to what Bill has said, except to the question of bags vs filters.

I just checked Delta's site, and that 760 DC has a total bag area of 20.5 square feet of bag filter area.

There are two filters that Wynn seems to recommend for doing the bag to cartridge conversion, the 35A100SBOL and the 35A274SBOL. the first has 100 sqft of cartridge filter area, and the second has 274 sqft.

The Torit filters I use on my cyclone have 226 sqft each (I have two filters).

With the smaller of the Wynn filters you are still getting nearly 5 times the filter area, thus your possible airflow will be much, better, with the 274 sqft, it is 13 times the filter area.

Now once the bags get dirty, the actual sqft drops a lot.

With a good cyclone, your filters don't see hardly any dust, so you get a constant high potential air flow.

If that makes sense.........:o

Cheers!

[Jim Becker]

I guess the next question is how can I find the curves for other collectors?

Very difficult, if not impossible, unless the unit you are considering was reviewed by a magazine that actually did testing. The fan curves would be almost "anti-marketing" for the manufacturers! Most of this has been with cyclones, not the single stage systems. Most of the single stage systems can move about half of their manufacturer "specification" relative to CFM with appropriately sized duct work, but there is no guarantee of that.

[Bill Pentz]

Jeff, the FWW curves are probably the most accurate comparisons I have seen to date, but you need to remember that this testing leveled the playing field by testing whole dust collectors instead of just the blowers, plus all were tested with the same lower resistance high airflow fine Wynn filter instead of stock filters. I remind all that you need to put a heavy piece of window screen in these units to protect that filter (see my pages for more info).

Prior Wood Magazine and American Woodworker Magazine fan curves and recommendations had problems. They really should have had an engineer look at the fit, finish, design, and construction because most of the import blowers were just plain bad with major copying errors. There also were serious testing problems using inappropriately sized test pipes, failure to use an amp meter, some vendor funny business where motors and impellers were tested that did not match the products being sold, and some serious graphing problems. Careful examination of their graphs showed somehow the individual graphs, probably from MS Excel that automatically scales, were merged without converting each to the same scale. The results rewarded marginal performers and wiped out good performers.

Although the best testing to date, even the FWW tests have some problems. Again, our dust collector and cyclone blower impellers are sized to not burn up the motors in a minimal resistance configuration and still provide as much airflow as possible. This means that if a firm uses a larger impeller risking burning out motors if there is not enough resistance, they get to “win” the magazine rating wars. They will continue to win until the magazines test with an amp meter and throw out all CFM readings that exceed the motors’ rated amperage. FWW failed to use an amp meter so continued the not good practice of publishing portions of the fan curves that we know push the motors far over their maximum rated amperage. If you were to add the minimum resistance for a standard 10' long 6" flex hose connected to a large two port tool, that resistance leaves none of the portable dust collectors able to move the minimum 800 CFM needed for minimal good fine dust collection. It gets worse because that testing also did not adjust down the roughly 10% needed to compensate for only taking a centerline airflow. Still, FWW did a good job blowing through the confusion of just testing blowers. The FWW tests give real performance in a working system with a consistent filter. That saves having to add all of the various resistance overheads that make a huge difference in dust collector and cyclone airflows.

So you are correct, even that “best” Delta portable dust collector with the upgraded lower resistance fine cartridge filter is probably not going to give you the airflow in real use needed for good fine dust collection in spite of these being excellent "chip collectors". If you check, you would see the Grizzly tested has been a top scorer in those tests that looked at larger 2 hp dust collectors. This means most of the 2 hp dust collectors also have a problem moving the needed air if burdened with ducting or more filter resistance.

I published the fan curves for the 2 hp and larger blowers used on most hobbyist dust collectors and cyclones based upon my own testing. For what it is worth, the FWW testing confirmed my own with Jet and Delta getting top ratings because they are the only two firms of the many I have studied in depth that use really well engineered blowers and impellers. My worsening health left me unable to keep up this testing. I finally pulled down my testing curves after getting beat up pretty badly for not keeping that information current. I agree that many of the vendors that had “worst” performances on my curves fixed their problems, but none went the next step to actually move from “chip collection” into good fine dust collection airflows. A commercial blower fan curve will pretty much limit the high end of what you can expect from your dust collector. My below graph gives actual curves for real hobbyist dust collectors, but I pulled the names to save some embarassment. For cyclones you need to add as much as 3.5" for the cyclone overhead in some cases as much as 5" more for filter overhead. So far, I think FWW has the only curves you can trust to get a good idea of performance. I know Michael Standish has already completed his cyclone tests that should be pubhished this fall.


http://BillPentz.com/Woodworking/Cyclone/DCBlowerComparisonGraph.gif

Although most probably do not want to hear me, I said you need a 3 hp dust collector turning a 13” impeller or 5 hp cyclone turning at least a 14” impeller to move the roughly 1000 CFM needed to meet the volumes of air needed to get the air quality standards already adopted in Europe that most medical experts recommend for good fine dust collection at your larger tools. I also said that dust collectors need to go outside and cyclone filters should either be tossed or put outside with fine open flow filter bags because fine bags and cartridges too quickly self-destruct when used indoors on most dust collectors and cyclones.

Hi Stu!

Changes made because I linked to the wrong graph.

[Bob Dodge]

Hi Jeff,

The required static pressure for "small shops", cannot be "generalized". When you look at a static pressure curve, it basically tells you what your dc placement and duct-run options are. In essence, you have control over how you use the available static pressure.

If you decide to place a marginal dc, in a "convenient" location which happens to be at a distance from a machine, you may be short-changing yourself. Part of the available static pressure, will have to deal with the added pipe length and fittings. It's really "in your hands" to decide where you place that dc in relation to your machines.

If you're going to go with a marginal dc, you have to be diligent in grouping specific machines and use short runs. If you do so, you will be no better off with a slightly more powerful dc, which is placed "at a distance".

Set your desired CFM target for the machine in question, look at your static pressure curve, then create the conditions for meeting that static pressure point. Allow some margin for pressure-drop at the filter as it loads. You create that margin by using a large diameter pipe, but not so large that velocity falls below specs. You want at least 3500 FPM through that pipe, or 4000 FPM in a vertical. The type of hood used, will have a profound impact.

Here's an example using the Delta 50-760 that you mentioned, and a large planer that has a 6" hood and an 800 CFM requirement. Let's for the sake of this example, use the FWW Magazine figures. The test result stated 800 CFM @ 4.5" sp.

Well, if you tried pulling that 800 CFM through a 5" pipe, you'd have unnecessarily high velocity in that pipe, which also means a very high static pressure reading. An 11 foot length of reasonably smooth-walled flex, with a 60 degree taper hood, would have 4.5" sp at 800 CFM. (no elbows) Add a 90 degree elbow, and you'd have to shorten your flex-pipe to 7 feet to stay within that 4.5"sp range. That's allowing nothing for pressure-drop at the filter. You'd have to shorten that 5" flex-pipe, to 2 1/2 feet to allow for a 1" pressure-drop at the filter. The point is; your velocity would be at a ridiculously high level. 5870 FPM. That's totally inefficient and unnecessary. So, what do you do? You go to a 6" pipe of course. That'll bring that excess velocity and static pressure, wayyyy down, and you'll STILL have all the velocity you need.

Using the same figures of 800 CFM at 4.5" sp, you could run a 45 foot long 6" galvanized pipe, with the same tapered hood, and that same 90 degree turn, AND, that would be allowing for a 1" pressure-drop as the filter loads. The ducting I mentioned, would by itself produce only 3.5" sp.at 800 CFM. Velocity would be 4076 FPM.

What's important here, is to not allow yourself and your dc's capacity, to be controlled by components like cheap $3. plastic hoods with 4" ports, and inexpensive 4" flex-pipe. Plan those pipes properly, and you'll get a heck of a lot more out of your dc than you could have imagined. That convenient trip to the borg for 4" flex and fittings, costs you a lot more than you think.

Bob

[Bob Dodge]

Stu,

The filters have very little impact on the overall outlet resistance. That limitation occurs primarily at the blower outlet. Here's an example.

The Jet DC-1100, flowed roughly 900 CFM WITH the cartridge filter. Without the cartridge filter, and only a single 14 sq.ft. filter-bag, it flows 860 CFM. The difference, was only 40 CFM. Roughly a 4% improvement.

The Delta 50-760's needle-felt filter, is roughly 50% larger than the Jet's, at 20.5 sq.ft.

Bob

[Bob Dodge]

Very difficult, if not impossible, unless the unit you are considering was reviewed by a magazine that actually did testing. The fan curves would be almost "anti-marketing" for the manufacturers! Most of this has been with cyclones, not the single stage systems. Most of the single stage systems can move about half of their manufacturer "specification" relative to CFM with appropriately sized duct work, but there is no guarantee of that.
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Jim,

As a general rule-of-thumb, you could generally state that CFM would be 1/2 of the "FREE-AIR" rating would be, but not 1/2 of a "test-result". You have to be careful though. "Claimed" free-air delivery ratings can vary widely with the "colour" and "manufacturer/re-sellers" brand label, even though both dc's are identical in every respect. Free-air delivery, is a useless, meaningless rating.

While there are few test results available out there for consumer-model single-stages, they are available with a little detective work. The June 2000 American Woodworker test-result, is one example. The recent Fine Woodworking Magazine test, is another.

While the test procedures themselves may have produced some higher-than-actual CFM results, they were accurate in the sense of the static pressure generated in the test-pipe, and, to illustrate the "difference" between one dc and another. All dc's were tested using the same method.

Bob

PS. The dc's were also tested with the same "seasoned" filter.

[Jim Becker]

-As a general rule-of-thumb, you could generally state that CFM would be 1/2 of the "FREE-AIR" rating would be, but not 1/2 of a "test-result".

Correct. I misspoke...and actually meant what you said. Sorry...

[Jeff Cord]

I'm already planning on keepig the DC portable and moving it to the machines.
So hopefully that will simplify things somewhat.
It also sounds like, since for the moment I'm looking for a more portable machine, I should stick with a Jet or Delta as those have better engineering.
I also plan on purchasing the hose from Wynn (smooth walled type).

I'm getting a feeling from some of the comments that having too little SP is also not ideal. That you want to get a balance from all elements of the system (hoods, ducts, connectors, DC) so that you don't get too much air velocity either.

I guess this type of confusion is typical for beginners?

[Bill Pentz]

Jeff,

Your confusion is normal. We have no less than four formal standards for air quality, at least four different approaches and minimums for picking up sawdust, and more opinions on filters than you can shake a stick at. My recommendations are based on landing in the hospital after buying the best available cyclone and top quality filter.

I think whether you have $200 in hand tools or a shop full of dedicated stationary power tools you should provide ample dust collection to protect your health and the health of those close to you. The risks are very similar to smoking tobacco where it takes one or more decades for the damage done by fine dust to build into serious health problems, but almost all are affected. My own testing has me convinced that moving less than 800 CFM at our larger tools will miss much of the finest most dangerous dust. My own testing also showed me that almost all available hobbyist and small shop dust collectors and cyclones come with filters that are far undersized so will soon self destruct, and lack ample filtering to provide good protection from the 2.5-micron and smaller particles known to cause the most long term health damage.

I advocate the medical air quality standards that are already the requirement in Europe. Reaching these requires fixing our tools with appropriate hoods and ports that don’t let the dust spray all over before it can be collected, moving roughly 1000 CFM to our larger tools and dustier operations to collect that dust, and then getting rid of it. Most hobbyist portable dust collectors claim huge airflows, but as shown and discussed, most when challenged by the overhead of minimal ducting will not even move the 800 CFM needed to meet OSHA standards. I recommend either working outside or blowing the fine dust away outside, but if you can’t do that use at least 0.5-micron filters with a surface area of one square foot of all polyester felt filter area for every 4 CFM of airflow or double that if you use paper poly blended filters.

[Bill Pentz]

Jeff,

I have additional information that may be of use, but we need to take that off-line. Email me if you would like to discuss this further.

bill
bpentz@cnets.net

[Bob Dodge]

I'm basically in agreement with Bill, although there are a few points worth mentioning.

Re. Amp-Draw.

It may be a good thing to include amp-draw in test results, however, in my experience, most consumer-level dc's will never exceed the motor's full-load amperage to begin with. Many are severly restricted at the outlet, precisely to limit airflow. Why "limit" airflow if you're designing a dc? Simple. Warranty repairs. The limitation, is placed where the end-user is least likely to defeat it. Anyone can remove filters and vent outdoors, but not everyone is going to perform metal-surgery on a bag-tree, to increase the port diameter to 6" instead of 5". Also, there has been a recent appearance of two-piece clamshell blower housings. No "removeable" 5" outlet transition-flange.

Small industrial single-stage dc's, routinely deliver beyond full-load amperage levels with a 10 foot test-pipe. Why? Because they use far superior motors, and are "optimized" to deliver full BHP capacity to the machine. In other words, they'll run at full-load amperage even with a 20 foot length of flex-pipe. These guys warn you also. Use the dc unrestricted, and you'll void the warranty. Many of those dc's have service factor ratings of 1.15, and have "continuous" duty-cycle operation levels. They can be run all day long, with a 15% overload, and no adverse thermal effects.

I recently tested my own small industrial single-stage dc. A Pyradia/Belfab 2hp unit with 12.5" impeller, and 2 hp Baldor Industrial Premium Efficiency motor. With a 10 foot test pipe, 6" diameter "plain-end", the unit flowed just under 1100 ACFM (actual CFM) at 4.7" sp. This was with a "dirty" but shaken filter, Amp-draw was 10.7 amps. The motor's F.L.A. is 8.5 amps.
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Re. Bill's Blower Test Chart,

The figures for the 1 1/2 hp dc on that graph, are really "off". That would have to be one poooorly designed 1 1/2 hp dc, to pull a max 600 CFM at 1" sp. Even a decent 1 hp dc will whoop that figure.

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Re, "Euro Standards".

I'm in FULL agreement, but, to a point. I would never categorically state a figure like 1000 CFM at all machines. I'd much rather have 800 CFM of "Effective" collection, than 1000 CFM of general airflow. The hoods and efficiency of the collection points, is paramount. There's no point getting a 1000 CFM sucked through the base and the handle-slots on a table-saw, then, having no overarm blade-cover on that saw. 1000 CFM would be a useless and inefficient flow without that blade-cover. Ask anyone who's used an Excalibur, or a well-ported shop-built unit. If you work MDF, Melamine, or particle-board, you'll know what I mean.

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In conclusion, when someone comes to me for ducting advice, I'll do my darndest to help that fellow get the most from his dc, regardless of whether that's a small dc, or a big honking dc. To me, it's irrelevant. I'm neither "impressed", nor "un-impressed". All I see is "static pressure" and I go from there. We all grow our shops at a rate we can afford or as our requirements change. I'd rather see a guy at least get started with dc's by purchasing something like that Delta 50-760. Nothing will touch it in this price range, or hp category. Use it wisely, and within it's limitations, and you'll be a happy camper 'til the need comes to up-grade. Anyone with respiratory issues, who's not working with an appropriate dust-mask, is asking for trouble with ANY dc.

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Oops, a few more points;
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Re. recommending 3hp, 1000+CFM dc's,

In a heart-beat, "IF" you have the machines, the budget, the power source and the space. Most exceed the 8 foot ceilings that limit so many of us. 9 1/2'- 10 feet is common. Aside from that, there is machine-port sizing, and lack-of-availability of single-phase motors. These units are the back-bone of many small commercial one-man shops, with 6" ported machinery. If you got 'em, go for it. A 3hp Pyradia/Belfab "LW" for example, will pull 1400 ACFM at 8.5" Static. All blowers are AMCA accredited ratings.

Would I recommend that 3hp/ 1000 CFM dc to a guy with a 12" lunch-box planer, a 6" Home-Depot jointer, and a contractor saw? Not on your life.

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What are my "Pet Peeves" regarding home-shop dc's? Using undersized ducting and inefficient hoods at chop-saws, radial-arm saws, drum sanders, and above all else,,,,,,,,, 4" porting on down-draft tables. That's a real "no-no" in my books. ALL of these machines and devices are notoriously "dirty". We need to re-examine our views at these stations.

Lathes, are in a caregory of their own.

Bob

[Jesse Cloud]

Jeff,
As you have probably figured out by now, Dust Collection generates as many arguments as religion and politics (which are both banned on this site).
If you have a small shop, I would recommend two things: 1)get a decent portable unit (Delta, Jet, Penn State) and plan to hook it up to whatever machine you are running at the time. This will give you some experience with the pros and cons of different DC techniques. If this doesn't solve your problem, then sell it in a year (you can usually recoup about 50% of the sales price on used tools) and put the proceeds toward a central system. I have an Oneida and I am constantly fooling with ports and pipes years later, but I wouldn't want to be without it.
The second reco is to get an air filtration unit - this guy picks up dust in the air that DC misses. You need this because no DC I have ever seen comes close to 100% efficiency on miter saws, routers, sanders, etc. The air filtration unit should cost about $200 and you will notice the difference.
Main thing is don't let the gurus intimidate you into analysis paralysis. Do something!
My two cents.

[Bill Pentz]

Jesse Cloud hit the nail on the head about dust collection generating plenty of controversy. Like smoking tobacco most are affected over time, with some suffering seriously. Unless you have a violent allergic reaction, most need a few decades before getting ill, so dust collection becomes something we can easily ignore. Jessie is also right that dust collection becomes a never ending project as I have been messing with my dust collection for at least eight years with no relief in sight.

I don’t agree with Jesse’s recommended temporary or his personal solution any more than I agree with much of Bob Dodge's practical solutions. Arguing and telling people they are wrong just hurts feelings and wastes time. Small shop dust collection is now in transition and things will continue to get uglier before they get better. I also had to use an air cleaner with my Oneida-Air cyclone and fine filters, but just wish I had been smart enough to realize the dust that was not collected or went right through the filters continued to build to dangerously unhealthy as my respiratory doctor later said. I diligently wore my 3M NIOSH dual cartridge mask when making fine dust while working on Christmas gifts made from fairly toxic wood. What I did not realize is every time I went back into my shop, the air from my tools, dust collector, vacuum, and air compressor launched airborne the mostly invisible “fugitive” dust that previously escaped collection. I probably would have been just fine had I kept using the big exhaust fan and regularly blowing my shop out with my compressor or leaf blower after working. I did not and landed in the hospital. My “clean” shop went unused for three months before I had a medical air quality test run to see if my doctor was right. My inspector's test equipment showed before doing any woodworking, just turning on my cyclone and air cleaner pushed enough of that “fugitive” dust airborne that the airborne particle count went in excess of 12,000 times higher than considered medically safe. Just a little woodworking busted the OSHA 15 minute maximum and pushed the overall eight hour average airborne dust level to more than double the allowed OSHA maximum. It took over six more hours for my air cleaner to pull the dust level down enough to be considered safe enough to work without a mask.

If you get serious about better protecting your health and the health of those close to you, then you need to decide on how much fine dust protection is enough, and put it in place for yourself. I don’t think any vendor can deliver a working solution that does not take quite a bit of effort on our parts to make viable. For at least five years my web pages have consistently said good fine dust collection requires fixing our tools so they don’t spray dust all over, moving enough air which takes a big enough blower and ducting, and then getting rid of the fine dust. I prefer to see the fine dust get separated by a cyclone and then blown away outside, but many like me must filter. Because few dust collectors or cyclones move enough air and most fine filters are so small and open they fail to protect our health and quickly self destruct, I suggest you do your homework.

Sorry I don’t have a simple buy that one solution that is cheap and easy.

[Stu Ablett in Tokyo Japan]

Jeff, the solution is simple.

Buy or build a cyclone, the only ones that are using Bill's design are the one you build (like I did) or the Clear Vue, which uses Bill design.

Buy a motor, buy an impeller, and build the blower, it is easy to do, our very own Julio, down in Florida has done this.

Once you have a well built blower, with a good impeller and a good motor, then you add a good cyclone to it, and you are set.

Or you can do as I did, I bought a used "good" (HA!) DC, and filled my lungs and Dungeon with dust, then, I built the Pentz cyclone.

Check out my website, I put a bit of work into the cyclone and I documented it fairly well, I think.

You can pay a little now, for the portable Delta or Jet, but it is just a chip collector, it will NOT get all the fine dangerous dust. If you can open all your windows and your garage door, and run a big fan, while wearing a good respirator, you should be fine, but if you want to do it one time, and one time that will last a very long time, do it right from the start, you WILL save money, and your health.

Your call, but if I can build a cyclone in my Dungeon workshop in the middle of freaking Tokyo Japan, TRUST me you can do it where you are (I am assuming you are in the US or Canada).

There, off my soap box, not trying to start a fight with anyone, I'm only trying to give you the benefit of myself going through exactly what you are starting.

Cheers!

[Bob Dodge]

Konichiwa Stu,

Are you still using the same blower you had on the old dc? Did you ever get that 6" blower outlet issue resolved?

Bob

[Stu Ablett in Tokyo Japan]

Konichiwa Stu,

Are you still using the same blower you had on the old dc? Did you ever get that 6" blower outlet issue resolved?

Bob
HI Bob

I've not had to do anything to it, the performance of the unit is more than satisfactory, the only machine that does not work so well is the Bandsaw, but that is not a fault of the cyclone, but of the Bandsaw design, as it is completely open on the back, but the cyclone still gets most of the dust, and the fine dust for sure.

I'm VERY please with it, and the separation is out standing.

I've now run over 2500 liters of dust through it, and I've yet to reach the 1/2 teaspoon level of dust in the clean out, and that is after banging the filter stack, and using compressed air to back clean the filters.

I'm getting darn near no dust reaching my filter stack.

http://www.ablett.jp/workshop/images/cyclone/filter_stack_cleanout_drawer_check.jpg
Clean out

http://www.ablett.jp/workshop/images/cyclone/bags_of_sawdust.JPG
Bags of sawdust.

Cheers!

[Bob Dodge]

Stu-pendous Stu-ff Stu,:D

What size impeller does that blower have? Inlet/outlet were both 6" weren't they? Been a while. I know a guy who wants to add a passive cyclone stage to his old 12" impeller blower. You're set up in "push-through" mode, aren't you?

Bob

[Stu Ablett in Tokyo Japan]

Hi again Bob.

It is pull through, we looked at doing the push through, but due to space limits.......

The impeller is a big one, 38cm if I recall, just a tad below 15", the motor is 2.2 Kw three phase...
http://www.ablett.jp/workshop/images/dc/dc_motor_plate.jpg
I wish the RPMs were higher, but it seems to work very well.

I know I could tweak it some, and I may one day, but for now it works very well, and I'm dust free, so I have other things to spend my time on.

Cheers!

[Gerard Pauwels]

Stu

Read a post on another board re: Clear Vue that fine dust was collecting on "ramp leading down into cyclone." Wondered if you had ever disconnected your cyclone from duct and if you found similar build-up?

Gerry

[Bill Pentz]

Gerard,

With my cyclone design there is too much airflow for dust to collect on the air ramp upper surface and no problem with dust accumulation.

The lower surface of the air ramp in a cyclone encloses a dead air space where there is almost no airflow. We can keep all dust out of that space by sealing it tightly, but that means we could not take our cyclone apart easily if we need to clean. After mine stole a long stick that jammed in the air ramp, I decided they had to be made to come apart. This means my design, whether made by Clear Vue or from my plans, seals the outside edge of that ramp and leaves the inside edge where there is almost no dust travel open. Some fine dust can seep through this gap into that dead airspace. Because I left the bottom of that ramp open, it will just fall out. With the Clear Vue showing all, some have noted that they can see a tiny amount of this dust in that dead air area. It eventually drops out the opening at the bottom of the ramp that exits on the outside surface of the cyclone to be separated away. There is nothing to worry about at all. I am sure Stu gets a little of this fine dust, but without clear sides he would never see it. His dust bin confirms it does get separated off nicely.

[Bob Dodge]

Interesting Stu,

I remember we had talked about the 2860 rpm 50 hz motor, but I didn't remember talking specifically about the impeller diameter. The tip-speed on that 38 cm impeller, would be roughly 127.5 mph. Roughly the same as a 3450 rpm 12" impeller. (123.1 mph) The 12.5" impeller on my dc, is 128.23 mph (3450 rpm)

I don't suppose you'd know the blade-height off-hand? What about the number of blades?

Bob

[Stu Ablett in Tokyo Japan]

Interesting Stu,

I remember we had talked about the 2860 rpm 50 hz motor, but I didn't remember talking specifically about the impeller diameter. The tip-speed on that 38 cm impeller, would be roughly 127.5 mph. Roughly the same as a 3450 rpm 12" impeller. (123.1 mph) The 12.5" impeller on my dc, is 128.23 mph (3450 rpm)

I don't suppose you'd know the blade-height off-hand? What about the number of blades?

Bob
I think I have a pic of it somewhere Bob, but I do not remember off hand.

The system works very well, it separates the all the dust, even the super fine stuff.

My filters are nice an clean, and and I'm very happy about it. :D

Cheers!

[Stu Ablett in Tokyo Japan]

Stu

Read a post on another board re: Clear Vue that fine dust was collecting on "ramp leading down into cyclone." Wondered if you had ever disconnected your cyclone from duct and if you found similar build-up?

Gerry
No I have not, and Bill addresses your question better than I could.

Cheers!

[Rob Wilson]

Bill,
In your graph what exactly is an Airfoil vs. an Impeller?

[Stu Ablett in Tokyo Japan]

I'm not Bill, but I think I know the answer....;)

It is a type of impeller.

38126
This is the typical material handling backwards vane impeller, it is made from steel, and has the fins riveted on. It can take hits from small pieces of wood and such that can get sucked into the system.

38127
This is an airfoil impeller, it is much more like a caged fan, and is much more efficient, but it is not nearly as robust, and would not take hits from chunks of wood very well.

If you are building a pull through cyclone, that means the blower is pulling the air through the cyclone on the out side of the cyclone, the filter side, after the dust gets separated from the air stream, so you have very clean air going over the blower, an airfoil would be good, if you are building a push through type of cyclone, where the blower is before the cyclone, and all the chips and dust will hit the impeller, then the airfoil is not a good choice.

Bill has extensive pics and text on this subject on his site, you can Google Bill Pentz Cyclone and find it.

Cheers!

[Bill Pentz]

Thanks Stu for sharing the impeller pictures. A picture is worth a thousand words.

The blue airfoil in your pictures is the unit I had custom made to permit powering my cyclone with a smaller motor. It was made with far heavier steel blades than most airfoil impellers so those blades can handle material hits, plus it has a special additional center blade to help deal with the problem of airfoil impellers stalling at around 7” of pressure. Stalling generates nasty vibrations that will ruin motor bearings if allowed to continue. Because of this stalling problem and because airfoil impellers also must be regularly inspected and cleaned to make sure they do not build up debris that could put them out of balance, most use self cleaning material handling impellers like the red Jet impeller pictured. If you are willing to do that inspection and cleaning, plus have a small enough shop that the resistance does not cause a problem, airfoils at almost double the efficiency will let you move more air with a 2 hp motor than you could move with a big 3 hp.

[Bob Dodge]

Here's some info on a line of airfoil impeller blowers from Cincinatti Fan.

Basically, an airfoil impeller resembles a caged back-inclined impeller. On the B.I. the blades are flat, and the airfoil's blades, when viewed in cross-section, are shaped like an airplane's wing. (Curved top surface). The airfoil is more efficient, but is used strictly for "clean-side" operation. An example would be on a bag-house dc, where the filtration stage occurs before the blower stage. Commercial industrial cyclones tend to use back-inclined impellers.

http://www.cincinnatifan.com/NEWPDFs/HDAFinternet.pdf

I have a fairly large airfoil impeller, with roughly 16" fan-wheel. It's rated to 2400-2700 CFM, and powered by a 1/2 hp Leeson motor. Belt-drive, and currently set -up for roughly 1125 rpm. Static pressure configuration is quite low, at probably 1" sp or less. (15" pipe flange) The bell-mouth entry, is actually smaller, at roughly 10" across, and narrowing to roughly 7 1/2"-8".

I'll be replacing the current motor for use in a large down-draft table, and rpm will be set at roughly 1800-2000 rpm, for 3000 CFM at 3" sp. A 3 hp motor will do. (roughly 2.4 - 2.6 bhp)

All waste will be contained and handled within the down-draft table, with a built-in pre-blower filtration stage.

Bob

[Bill Pentz]

Here is a simple picture from my web pages that shows the various types of impellers used in dust collection: http://billpentz.com/woodworking/cyclone/airfoil.gif The backward inclined (B.I) and backward curved (B.C.) impellers make less noise than the radial impellers. Most use curved impellers blades because they cut the noise and are more efficient than the straight. If the blades are airfoil shaped they generate high and low pressure areas that actually move more air more efficiently. Unfortunately, the air will spill off the top of the blades unless we trap it with a cap, better known as an impeller cage. The top that sits on the airfoil pictured is an example of an impeller cage.

You can put this kind of cage on the other impeller types, spin the impeller a lot faster, and build much higher pressures. In fact, this is exactly how a vacuum cleaner blower works and the type of impeller they mostly use. Caged impellers will build up strings and shavings creating balance problems that will soon destroy motor bearings, so are mostly used after the filters or in heavy duty ventilation and air conditioning (HVAC) systems in clean air because they are so efficient. This same efficiency makes them one of the best to also use in dust collection, but this requires heavier blades and regular cleaning to ensure they do not go out of balance. The airfoil impeller I helped custom engineer generates a maximum of about 9” of static pressure, but should be run at under 8” because even with the special center vane, it stalls at higher pressures.

[Alan DuBoff]

Bill, was just curious, could you enlighten me about the motor? I have an area which can be used for the dust collector in my garage/shop, which has a 220 outlet by the area.

I was reading on your site about the motor, and it seemed you reccomend a Delta 2HP motor which can be bought off ebay. I get the impression from your posts that getting a 3HP or even a 5HP is desirable.

Since the motor is the base of this project, it seems wise to get the best motor as possible.

I only have single phase on the 220, I believe, so would like to find a motor that is single phase to accomodate it. Any advice on the actual motor, and getting one with more than 2HP so the fine dust gets picked up nicely?

[Stu Ablett in Tokyo Japan]

Bill, I for one greatly appreciate you honest, factual research and constant desire to learn more about all of this.

You have taken your very unfortunate personal circumstances and looked for the silver lining, or you got lemons and made lemonade, and the hobbyist world of woodworking is MUCH better off for it.

I know that without your tremendous help and your willingness to share your hard gained knowledge and info on this subject, I'd be saddled with a really dusty shop, and I would not be able to run most of the tools that I have for the long term in my Dungeon. In fact, I have no doubt that without your very generous commitment to "Spread the word" I would have remained ignorant of the health risks and I could very well have destroyed my lungs down there in the Dungeon.

Kudos to you Bill for your honesty and your help.

You are "Da Man" when it comes to this stuff, and I have the proof sitting in my Dungeon.

http://www.ablett.jp/workshop/images/cyclone/cyclone_finished%21.jpg

Cheers!

[Bill Pentz]

Alan,

The heavy duty 2 hp Delta motor recommended on my web pages is for those who would like to power my smaller airfoil impeller design. Eric who used to sell these new motors on eBay (TheGoodMemeber) for around $89 is out of inventory. He is trying to find more, but not having much luck.

If you are going to go with a material handling impeller as most do please get the best quality motor you can afford because it will be the most heavily used in your shop. Ideally a big industrial 3-phased motor with variable speed control and oversized impeller would give you the most control, but providing 3 phase power and speed control is way too pricey for most. Although I know by wheeling my 1.5 hp dust collector right next to my machines and using 6” duct will almost do the job, I still suggest using either an outdoor dust collector with 3 hp 240V motor or a cyclone vented outside using a 5 hp motor. I personally like Baldor and Leeson compressor grade motors. Both are near silent running and will give years of service. Electric Motor Warehouse has very good buys on the bigger 5 hp Leeson compressor motors all setup and converted for a face frame mount at the best price I have found anywhere. You can also buy the motor, impeller, and blower housing from Clear Vue Cyclones.

Many find that the larger pump motors make excellent dust collector motors and really excellent units are available rebuilt from pump shops, swimming pool suppliers, etc. for under $100. Adding a good quality impeller such as Ed Morgano sells, or the other suppliers recommended on my web pages will let you build either a nice dust collector or cyclone and still have less invested than a new good quality 1.5 hp portable dust collector.

[Bill Pentz]

Thanks Stu, I do try my best.

[Chris Padilla]

http://www.sawmillcreek.org/showthread.php?t=9933

Check out my build of the BP/CE cyclone. It is a thread worth going through and I may one day continue to update the sucker! LOL :)

[Alan DuBoff]

Bill, I'm about to show some of my ignorance. I am not exactly sure of the difference between single and three phase circits, and all I know is that I have a 220v circit that was run to my garage, and one in the home for the washer/dryer. Turns out I'm not using the washer dryer plug, since I do not have an electric dryer and my gas dryer uses 110v. The washer only uses 110v. In my recent quest to organize my garage, I found yet another 220v plug, and actually a double 220v outlet (i.e., 2 female plugs). Is this like pennies from heaven or what?

I am assuming this is single phase, and a friend mentioned it costs quite a bit for a 3 phase converter. This implies that most probably use single phase, but I wasn't sure.

Both Stu and Chris have very nice DC units from what I can tell. I lived about 5-10 minutes from Stu's dungeon for about 5 years, and I agree with one of Stu's comments...that if he can build one of these units, most folks should have no problem, given some of the limitations of living in Tokyo. :eek:

However, Stu does have access to Akihabara, a great resource to electronic parts. Not sure if he got his motor there, haven't got to reading his DC web page yet.

Ironically, I am within spittin' distance of Chris, and I'll be picking Chris' brain for certain! ;) Luckily, we're all only a inet connection away these days and I'm grateful for those that have posted info on not just DCs, but all the information on the web, it helps and makes many of our lives easier, and Bill Pentz has one of the most talked about sites on DC that I know of, wether he is right or wrong there seems to be a lot of grateful readers of his site. The great thing is that we all get to draw our own conclusion.

I will check out the Electric Motor Warehouse, Bill, and see what type of prices the motors sell for. Maybe I can find a used one locally, or on ebay, I don't know.

[Stu Ablett in Tokyo Japan]

Allan, I very, VERY much doubt that you have three phase, it is an industrial thing.

I have it in the Dungeon, because we have it in the building to run the elevator, I just had them give me one three phase circuit for the Dungeon, as I knew that used industrial equipment is cheap here, as only factory kind of guys can use it, well that and nutty Canucks in Dungeons ;)



Bob, can I see the pics of you cyclone that you designed and built? Really, I'm interested in how yours differs from mine.

Cheers!

[Alan DuBoff]

Allan, I very, VERY much doubt that you have three phase, it is an industrial thing.Yeah, I didn't think so, but I'm not really good at electrical, and in fact I spent 2 weekends to make sure I was wiring a switch correctly for an exterior door light, wanting to make sure I didn't end up burning down the house.

Bob, can I see the pics of you cyclone that you designed and built? Really, I'm interested in how yours differs from mine.I'd like to see also. I like the looks of the clear vue cyclone, but it seems pricey at almost $400 for the cyclone alone, so I may be forced out of budget to build my own as you and Chris did.

Would like to see if Bob built one out of sheet metal/aluminum or went another route.

[Stu Ablett in Tokyo Japan]

Alan, I'll gladly answer any questions for you, I'm just no longer responding to Bob, as I don't think it is doing anyone any good, Bob, Bill, Jeff, you or me.

I'm not really exactly sure, the ceilings are less than 8', but I'd have to go measure them.

I've seen somewhere that Ed (it is Ed, right?) at ClearVue has put a cyclone at an angle, says it works good as long as the angle is not too much, maybe you could gain some ceiling height that way? Just thinking out loud here :D


Cheers!

[Alan DuBoff]

Stu, I think I have at least 8', and even some extra, I need to measure it. I am slightly constrained as it will go between the garage wall and the garage door (about 2 feet, I need to measure that). It looked big enough and has the 220v outlet by there.

I guess you'd get a bit more out of your motor if you took it to Osaka... :rolleyes:
<rant on="" japanese="" voltage=""></rant>

[Stu Ablett in Tokyo Japan]

What Osaka.......?

Man, I'll buy a step up converter before I move to Osaka.......... ;) (If you don't know, there is a H-U-G-E rivalry between the two cities).

Cheers!

[Bill Pentz]

I did not invent the air ramp, tilted inlet, or basic cyclone function. What I did was throw money at my dust collection problem, land in the hospital because the “best” cyclone, fine filter and ducting solution totally failed to protect me. Instead of whining I went to work to figure out what happened and how to make repair. I was shocked to discover my vendor lied badly because my cyclone was zero percent better at fine dust separation than my dust collector, moved less than half the advertised airflow, and passed almost all of the finest unhealthiest dust right into my shop air. That dust then built to dangerously unhealthy. My friends and I did the air engineering to improve the average small shop and hobbyist woodworking cyclone from close to 0% separation efficiency on 30-micron and smaller particles that ruin fine filters to about 48% separation by weight. That still ruined my new fine filters quickly, so I started over. Starting with the basic cyclone physics and engineering I designed a new cyclone from the ground up that used the best of the existing cyclone features, plus my own innovations that stabilized the airflow and reduced turbulence amply to push that fine dust separation efficiency to over 98%. Although I am not an air engineer, motor expert, medical doctor, or many other things, I did start off my career as a rocket motor engineer and in the following 39 years of engineering and university engineering teaching have picked a little real experience innovating air quality and vehicle emissions equipment. The cyclone engineering was hard work that took considerable time and money while creating a small mountain of almost good enough parts. I gave the results away for free so others could hopefully avoid some of the resulting health problems that I still live with.

Sharing my plans on woodworking forums got me buried in emails. Most had little problem with my cyclone design or engineering, but almost all needed relief on the very high costs for parts to step up to good fine dust collection, plus help with the incredible confusion and contradictory information. Getting better pricing took a lot of work to gather together vendors willing to help, but that was easy compared to responding to the information requests. There were at least four different airborne dust collection standards and many contradictory approaches. This field is also buried in its specialized language, terminology, and complex technical stuff that even with my engineering background and lots of help took about two years work before much of that confusion began to make sense. Once I knew what was needed, figuring out what equipment would meet these needs was near impossible because all small shop vendors provided near useless maximum performance claims, and many flagrantly lied. When people asked me questions I could not answer, instead of blowing hot air, I took the time to understand, test, and get help to make my answers viable and accurate.

The more I shared the more people wanted until more emails came in than I could possibly address. In self defense I shared my initial dust collection articles and cyclone design along with a FAQ on my web pages in March 2000. I fully admit my web pages were written by an ignorant university research engineer who often drops into teaching mode when explaining, but most seemed to understand and know I meant well with a goal of reducing the confusion, plus give affordable solutions that others could implement to protect their own health. I fully admit many mistakes and early confusion, plus am most thankful that many firms including Donaldson-Torit, Dust Vent, AAF, and many others including a large number of air engineers were kind and patient enough to help me through my confusion and help make that site more accurate and helpful. My goal was to make it easier for others to understand their risks, the risks to those close to us, and what the professionals have found provides the minimum to make repair.

I have formally helped WMH Tools (Jet, Powermatic, and Wilton), PSI, Wood Magazine, Fine Woodworking, and Grizzly consulting on their cyclone design, plus helped with many other dust collector and small shop cyclone efforts. Grizzly’s owner requested the WoodNet thread referenced be pulled down after finding his President did in fact use my help adopting my inlet design, blower recommendations, and part of my air ramp design. Although my friends and I were never paid or given credit, most current hobbyist cyclones now use the changes that I freely share on my Cyclone Modification web pages.

I personally started powering my own cyclone with a large Cincinnati Fan blower and impeller. It worked well, but was far beyond what most could afford, so I did the work to find viable alternatives. The Jet impellers proved to provide almost as good airflow as my Cincinnati Fan impeller, but the similar sized Grizzly and Delta replacement impellers did not do as well. That is why I recommended Jet and did the work to build a blower design you can easily build based on this impeller. When Jet ran out of inventory and people needed an alternative impeller source, I contracted with Sheldon’s Engineering to build an identical performing impeller with a much better compression arbor to hold the motor shaft. In the interim, many bought “clean air” aluminum light Cincinnati Fan impellers. These do move a little more air but some learned the hard way why I strongly recommended against them. A few exploded when hammered with the stuff that goes through a blower if the cyclone dust bin becomes full. A few also slid down their motor shafts because the set screws were not ample to carry the weight of an impeller on a vertical shaft. “Swing weight” introduces expertise to confuse that has little to do with actual impeller weight. The 14” Cincinnati Fan, Jet, Grizzly, and Sheldon’s are near identical in physical weight and swing weight.

A 3 hp motor proved too small to turn this sized impeller without risking burning up the motor with short big ducting runs, so I chose to upgrade to the 5 hp Leeson compressor motor. It had the needed quality, power, cost less than many of the 3 hp motors, and came configured with a face frame mount. Motor hp with vacuums and air compressors is a controversial topic that actually referred to a comment I made on the less expensive Harbor Freight compressor motors. Since putting up my web pages new amp/hp tables were issued and I recommend a top quality 5hp Leeson motor. After nearly a year of testing to ensure this was a viable solution, I finally upgraded to a larger 15” impeller to better use the available capacity with this Leeson motor.

Buy Filters is the retail arm for Donaldson-Torit, the dust collection firm considered the best in the industry by large woodworking facilities and those who do air quality testing. They manufacture a wide range of filters. I chose for my personal use and recommended a set of their filters based upon using their technical charts to match my expected dust loading and airflow, plus their advice to maximize surface area to extend filter life, reduce resistance, and reduce cleaning needs.




Edited to fix some careless errors and typos. Lunch was good and friends better.

[Steven Wilson]

...I can go on and refuse every single thing said by Bob Dodge, but instead I am going to move on and go visit with a friend for lunch.
Sounds like a much better use of your time :p Have a good lunch and thanks for all of your posts.

[Julio Navarro]

In reference to building the Pentz cyclone I can tell you first hand it can be done relatively easy.

Follow the instructions on Bill's site and you will not only enjoy and learn a few new skills but you will have built it your self.

As soon as I can get off my bum I will post my pictures.

[Ken Salisbury]

http://www.oldrebelworkshop.com/referee.jpg


I hate to have to take the time to be a referee.

However, This thread has evolved into personal and professional attacks and references to those attacks. I have edited content from several posts and deleted some posts which would have taken more editing than I was willing to do.

Lets remember to abide by the Terms of Service.

2. Disagreements, Flaming, and Personal or Professional Attacks
Disagreements are almost certain to occur. Members shall be respectful of dissenting opinions and refrain from name-calling, personal or professional attacks. Messages that contain critical content must provide all factual information pertinent to the problem and enough data to support any claims or complaints.

If you have a personal issue with any posters please handle it via e-mail or private messages. Any further posts referencing the attacks will be summarily deleted.



http://www.oldrebelworkshop.com/misc/moderator.gif

[Alan DuBoff]

Thanks Ken, right when I was starting to get to the heart of the info, attacks started to break out...hope it wasn't something I said, I don't think so.

What Osaka.......?

Man, I'll buy a step up converter before I move to Osaka.......... ;) (If you don't know, there is a H-U-G-E rivalry between the two cities).Oh, I know...but watch what you say about Osaka, that's the sister city to San Francisco! ;) And I love Namba, very similar to the Kabuki-cho in Shinjuku. One of the oldest resturaunts I've been to in Japan is located in Namba, it's an old oden resturaunt. Very cool place.

To be honest, I reccomend to folks that if they can get to Osaka, the voltage and cycles is the same as the U.S., so the products do not require transformers. Many products have multiple selectable transformers inside, to handle 100v, 120v, and 220v. It would not be so wise to have seperate manufacturing lines for each country. Problem is getting the schematics in some cases to figure out the wiring, if it's not obvious.

However, with this said, I am trying to get my head around building one of these, and there is a lot of options, so understanding this stuff seems to take a while to soak in, not only for me but most.

I will try to stop by and see Chris's cyclone in person, and be able to hear the noise level of the unit. Chris used the leeson 5hp and Sheldon 14" if I'm not mistaken. That seems to be one of the more popular setups, and seems that Allan Johansen used the same.

My other option was the 2hp, single stage unit from Penn State, it's on sale for $369 w/canister filter, not a bad price and would probably handle my needs. Just seems that the price to build a cyclone could be similar by the time I get the Penn State, and I would most likely have a much better unit by going with the cyclone. Seems a bit of time invested to build one can provide big payoffs.

Let's face it, I don't know one woodworker that doesn't care about having less dust, and a healthier environment in their shop, but to talk about DCs is much like talking religion for some reason...really gets folks blood all pumped up... :(

[Allan Johanson]

Ironically, I am within spittin' distance of Chris, and I'll be picking Chris' brain for certain! ;)
Chris loves BMWs so he must be a great guy. :D Definitely hook up with him and check out his cyclone.


Luckily, we're all only a inet connection away these days and I'm grateful for those that have posted info on not just DCs, but all the information on the web, it helps and makes many of our lives easier, and Bill Pentz has one of the most talked about sites on DC that I know of, wether he is right or wrong there seems to be a lot of grateful readers of his site.
I'm certainly grateful for all that Bill has done. He has not only come up with a great solution for us hobbyists to build ourselves but more importantly with the education aspect has helped kick the industry in the butt to help make better machines that will capture more of those nasty particles. People are able to make more informed decisions compared to several years ago.


The great thing is that we all get to draw our own conclusion.
Definitely. As you can see from the varying points in this thread, folks have different points of view which is cool. My only advice for the people out there who feel this topic is extremely important to them and trying to sort through all this, is to keep doing your homework.

Interpreting magazine testing articles can be problematic and from my own airflow testing I'm finding that the articles published in AWW or FWW are using peak airflow numbers. Subtract 10% for something closer to reality. Also, don't get blinded by the max numbers on the graph too. You won't see those in your shop when you get the ducting in place and the tool hooked up. So for those folks who have a certain airflow target in mind, be wary of magazine articles.

BTW, that not only applies to single-stage machines but to cyclones too. Using my Pentz cyclone for example, following magazine testing standards my cyclone will flow over 1700cfm. Wow!!!! Impressive, right? But let's focus on reality. I've measured the airflow at all the tools in my shop and with my combo of factory ports and homemade ones, the airflow at the tools will vary from 700cfm to about 1200cfm. That's a long way away from the 1700cfm a magazine would report.

Another conclusion I've formed through my own airflow testing is that filters do matter. I've tested typical working dust cake levels on a stock filter bag and an aftermarket filter bag on the same 2HP DC.

Bag #1 flowed approx 700cfm (peak) or 630cfm (average).
Bag #2 flowed approx 870cfm (peak) or 783cfm (average).

Comparing clean filter bags or going by marketing numbers of bags that will flow a certain amount of air per square foot - keep in mind that's when it's clean. Add on a dust cake and the airflow will drop. I don't see much use in looking at the airflow of a clean bag since it'll only be that way for a few minutes in a typical shop. :p

Alan, you got it right that I built my own cyclone with a 5HP Leeson motor and a 14" Sheldon fan. It's a great combo that makes for a very powerful DC. I really love the performance. In my situation with medical issues (both current and a concern for the future), I went big rather than try to get by with something smaller. If I was in the market for a DC today, here are my top three choices:

#1) Clearvue. To me, it's the clear (hee, hee) leader in the hobbyist market. Outstanding performance and a great value ($).
#2) Build your own Bill Pentz cyclone with a 14-15" fan. I went this route (before the Clearvue was available) and the performance is amazing.
#3) Oneida 3HP Super Dust Gorilla. Big machine by a big name in dust collection.

To reiterate, if dust collection is important to you and you want to take it seriously, start reading Bill's web site. Or you can skip ahead to the end and buy or build your own large cyclone and run 6" ducting to all your tools. Where appropriate, split the 6" pipe to two hoods on a tool like the tablesaw with an overhead DC port in addition to the port in the cabinet.

Done. :cool:

Cheers,

Allan

[Alan DuBoff]

Chris loves BMWs so he must be a great guy. :DHonestly, this is only because he's probably never driven a Porsche! :D But I do know Chris and he is a great guy, and he's got a cute kid to boot! (I have a soft spot in my heart for kids;-).

Definitely hook up with him and check out his cyclone.I'm gonna try to get to see it next week.

Definitely. As you can see from the varying points in this thread, folks have different points of view which is cool. My only advice for the people out there who feel this topic is extremely important to them and trying to sort through all this, is to keep doing your homework.Yeah, this probably can't be over emphasized, there's a lot of homework on this topic.

Alan, you got it right that I built my own cyclone with a 5HP Leeson motor and a 14" Sheldon fan.This looks like a great combination. This is what Chris has.

#1) Clearvue. To me, it's the clear (hee, hee) leader in the hobbyist market. Outstanding performance and a great value ($).
#2) Build your own Bill Pentz cyclone with a 14-15" fan. I went this route (before the Clearvue was available) and the performance is amazing.
#3) Oneida 3HP Super Dust Gorilla. Big machine by a big name in dust collection.I'll be honest, the ClearVue is not such a bad deal, considering you get a quality kit with all the components ready to go. As one starts to add up the cost of parts, buying similar parts will push things up close, if not more than the ClearVue, at least as I start breaking things down. The motor is about $250 from Electric Motor Wharehouse. The one area I could save money is in the cyclone, opposed to the nice plastic one supplied by Ed on the ClearVue, but Ed's unit is not gouging folks, IMO, and is a clean looking solution. For me the ClearVue is worth considering at $895 while I wait to do my taxes and hopefully get some $$$s back... :D

To reiterate, if dust collection is important to you and you want to take it seriously, start reading Bill's web site. Or you can skip ahead to the end and buy or build your own large cyclone and run 6" ducting to all your tools. Where appropriate, split the 6" pipe to two hoods on a tool like the tablesaw with an overhead DC port in addition to the port in the cabinet.Thanks for your input on this thread, and for your PMs, you've certainly helped me wade through some of this, and I do appreciate it.

[Stu Ablett in Tokyo Japan]

Stu, I think I have at least 8', and even some extra, I need to measure it. I am slightly constrained as it will go between the garage wall and the garage door (about 2 feet, I need to measure that). It looked big enough and has the 220v outlet by there.

I guess you'd get a bit more out of your motor if you took it to Osaka... :rolleyes:
<rant on="" japanese="" voltage=""></rant>

Hey, I checked, 248cm or 97 5/8".

Cheers!

[Alan DuBoff]

Hey, I checked, 248cm or 97 5/8".Darn if your dungeon isn't taller than it looks. The reason I asked is that I thought it was less than 8' for certain. I think I have similar, or can wiggle it, I think it's 8' to the rafters (open garage) but the motor should be able to tuck up in there.

I need to measure it, but I think I can get a couple extra inches on my 8' also. Then again, the footing might push it over 8' to the top of the wall, that I don't know.

[tod evans]

allen, is there some reason you must mount the pump to the cyclone top? it seems to me that mounting the pump either on the push or pull side of the cyclone would give you room for a larger collection container under the unit and alleviate some of your headroom issues...02 tod

[Chris Padilla]

My ears are burning with all this talk! LOL....geez, I didn't know you wanted to HEAR the cyclone running..... ;)

[Allan Johanson]

Honestly, this is only because he's probably never driven a Porsche! :D
Being a Porsche owner I know what you mean. ;) I give him a lot of credit for buying cars from the right part of the world though. How are your ears now, Chris? :D


The one area I could save money is in the cyclone, opposed to the nice plastic one supplied by Ed on the ClearVue, but Ed's unit is not gouging folks, IMO, and is a clean looking solution. For me the ClearVue is worth considering at $895 while I wait to do my taxes and hopefully get some $$$s back... :D
Taxes....ugh. :eek: I hope they work out for you. The Clearvue is a great solution for many folks so if you're thinking of that or making your own, there are lots of folks here that can help you get these set up. I have a ton of pics I can e-mail anyone who is thinking of making a cyclone (just drop me a line) and I'm starting to make a web page detailing the construction process since I get so many questions about it. It's not meant to replace Bill's or anyone else's, but rather a companion piece for more ideas on how to do this. For any person thinking of building their own cyclone I'd advise them to read as many different web pages as possible to see all the different kinds of approaches people have done. Then find a combination that works for you.

With all the resources out there nobody should feel alone when it comes to building a cyclone.


Thanks for your input on this thread, and for your PMs, you've certainly helped me wade through some of this, and I do appreciate it.
You're very welcome, Alan. My pleasure.

Allan

[Allan Johanson]

allen, is there some reason you must mount the pump to the cyclone top? it seems to me that mounting the pump either on the push or pull side of the cyclone would give you room for a larger collection container under the unit and alleviate some of your headroom issues...02 tod
Tod, this is a fine idea. I seem to recall either on Bill's site or on one of the forums out there an idea where the cyclone outlet tube that normally comes straight out the top of the upper cylinder, comes out the side of the cyclone for the ultimate in headroom help.

Later this year I might help one of my friends build something like this, but it probably won't be in time for Alan. When I do build one I'll document the process with plenty of pics and post it on the web.

Cheers,

Allan

[Bob Dodge]

Allan J. said;

"Another conclusion I've formed through my own airflow testing is that filters do matter. I've tested typical working dust cake levels on a stock filter bag and an aftermarket filter bag on the same 2HP DC.

Bag #1 flowed approx 700cfm (peak) or 630cfm (average).
Bag #2 flowed approx 870cfm (peak) or 783cfm (average).

Comparing clean filter bags or going by marketing numbers of bags that will flow a certain amount of air per square foot - keep in mind that's when it's clean. Add on a dust cake and the airflow will drop. I don't see much use in looking at the airflow of a clean bag since it'll only be that way for a few minutes in a typical shop. :p
-----------------------------------------------------------------------

Allan,

That must have been quite the 2hp dc you "tested":D

I tested a 2 hp Belfab JJ, with a top filter that had never been removed for cleaning, other than shaking it on the dc. 16 oz. needle-felt/ 32 sq.ft. Airflow with a 10 foot long, 6" diameter pipe, was just under 1100 ACFM, at 4.7" SP. The Baldor motor, was drawing 10.7 amps at that point, a full 2.2 amps beyond full-load amperage for that motor.

For comparison purposes, I totally removed the top filter to see what the "difference" would be with "zero" back-pressure from a filter. Motor amperage increased by an insignificant 0.4 amps, at 11.1 amps. The filter had been on that dc for 2 years at that point. I chose not to continue with an air-test, since I was well into the danger-zone. Full load amperage for that Baldor Industrial Premium Efficiency motor, was 8.5 amps/220v. S.F. rating 1.15, and 1.0 duty-cycle rating.(continuous)

The "difference" between a dirty filter, and no filter at all, probably places the clean filter about midway between those two points.

So, you're correct. "Filters" DO matter. "good" filters, vs cheap filters. Also, "good dc", vs cheap dc and so on. Concluding that "all bag filter dc's are the same",,,,,priceless.:D

Bob

[Julio Navarro]

Finally got some time to post some pics of the cyclone almost finished.

38286
The first is a pic of the main body being welded together.

38287
Painting, please note the SMC official colors:)

38288
I attached the motor and impeller and moved the blower and cyclone up under them. This was a BEAR...my son and daughter helped move the contraption I built under the cyclone.

38289
this is the contraption. Its on wheels.

38290
Here it is all installed!! Finally got there!!

[Julio Navarro]

...to continue.
38291
A side view

I will need to rotqte the cyclone towards the wall a bit as you can see the inlet is pointing to the middle of the shop. I thought it might be more efficient to go directly to the machines but after giving it some thought I've decided to run the ducts along the wall and then extend out towards the middle of the shop. I will experiment a little with bending the plastic pipe instead of using connections. I have an idea of how to heat the pipe to make sweaping bends using the heating elements from old toaster ovens. Wish me luck.

And of course I will also need the transition from 6" dia duct to 4x10 inlet. I will be getting the steel tomorrow and using the transition calculator on Bill Pentz' site links page. This is a nifty little tool!

38292
The bracket holding the motor. I got such good welds! This thing is solid!

The screws that seem to stick out of the top of the blower are extra holes I did not need, I will seal them when I do the ducting

[Frank Chaffee]

Julio,
Did you weld galvanized steel?
Frank

[Julio Navarro]

I scrapped to bare metal with a steel wire wheel on an angle grinder. But yes, to answer your question , I did weld galvanized steel. (was that a mistake? I read up on several welding forums and I didnt see any warnings except to wear a mask which I did)

[Frank Chaffee]

Julio,
First let me say that I have been very impressed with the progressions of your cyclone for as long as you have been posting it here. I love opportunities to layout conical sections on steel, and I envy you for having made your own cyclone, while I bought mine.

So glad you scraped to bare metal before welding, and that you wore a mask while doing it.

Speaking not from a medical background, but as one who welded for many years, I learned (?) that fine particles of zinc, freed by welding heat or even sanding, can be inhaled and become embedded in one’s lungs in much the same way that asbestos can. These inhaled particles will never be cleansed from one’s body, as they are barbed somewhat similarly to a fish hook.

I know that this is an aside to the DC theme of this thread, but I feel that it is important enuf a question to request opinions and commentary from qualified scientists.

Maybee im so goofy now cuz I did things like spray with leaded gasoline thinned paint, prepped steel for painting w/ lacquer thinner while clothed in a dust mask, and welded galvanized bolts.

I just hope that in my old age, I can help prevent debilitating shop practices for our progeny, who face enough challenges as it is.

Frank

[Julio Navarro]

Frank:
Your comment is much appreciated. I did read about the dangers of welding galvanized steel and I think I did follow good practices I used a good face mask and had what I thought was good ventilation around me while not dirtectly into the weld.

[Alan DuBoff]

Julio, that looks good!

[Allan Johanson]

Frank:
Your comment is much appreciated. I did read about the dangers of welding galvanized steel and I think I did follow good practices I used a good face mask and had what I thought was good ventilation around me while not dirtectly into the weld.
You did good, Julio. Frank, thanks for bringing this up. Welding galvanized metal is a bad thing. I did that once for a little bit of welding and I was messed up for three days. I then promptly bought a proper welding fume mask that would fit under my helmet.

Julio, I like your paint job on your cyclone too. It's fun having fun! :D One of these days I'm going to buy an airbrush (watched too many Overhaulin' TV shows with that darned Chip Foose) and let loose on my cyclone. It's solid black right now in preparation for the airbrush work. Since it's a very strong Bill Pentz design that will suck up anything, I'm going to honor it with the following idea:

I'll paint part of a solar system on it with a black hole in the middle. Above and below the painting will be:


Nothing escapes

[painting of solar system]

a black hole!


:D :D :D

Ya gotta have fun.

Allan

[Julio Navarro]

Nothing escapes

[painting of solar system]

a black hole!


:D :D :D

Ya gotta have fun.

Allan

EXCELLENT IDEA!!!

I was going to name mine the Hurriclone or the Cycane. Living in Florida I am intimately familiar with loud sucking sounds. LOL...

We have a flea market near by that has a booth run by a guy that does vinyl graphics for hot rods I think I am going to ask him to do a cyclone decal for me. If I see any planitary graphics I will let you know. He can do them any size, color font..you name it. May even be able to use as stencils for airbrushing, never know, I'll get back to you.

[Allan Johanson]

May even be able to use as stencils for airbrushing, never know, I'll get back to you.
Thanks Julio, that would be very cool.

I went on NASA's site today and spent about an hour looking at a ton of pics. Some of those pics are simply amazing. I'm getting inspired now....and that usually means trouble! :D

Thanks!

Allan