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Richard Butler
04-02-2007, 2:04 AM
I bought a new 50-760 DC. I now have to make some decisions and need a little advice.

My shop is 15'x30'.

The DC inlet port is 5"

I have included a not-to-scale drawing of my shop and the proposed DC runs.

The big questions are do I


1) make the run(s) using 5" dia pipe
2) make the run(s) using 6" dia. pipe.
4) make the run(s) 4" dia.

It would be best to place the DC centrally but that is just not possible.

Thanks

Wilbur Pan
04-02-2007, 8:50 AM
In general, it's best to make your duct runs with as large diameter pipe as possible. So if you can run 6" pipe, do so, and make the transitions as close to the machine and dust collector as possible.

Just to put some numbers on this, I'm guesstimating your long run from your router to your dust collector to be about 35-40 feet of ducting. You'll drop your resistance by at least 20% by using 5" pipe instead of 4" pipe, and by about 45% by using 6" pipe instead of 4" pipe.

Paul Dwight
04-02-2007, 2:10 PM
If it's possible, I might run a single main trunk line diagonally across the room, ending with drops for the router table and jointer. The tablesaw, planer and workbench could probably have simple drops directly off of the trunk line. Getting to the bandsaw would likely require a Y off of the trunk and a short section of pipe. The advantage of this layout would be minimizing the number of right angle turns, plus it would use less pipe.

If you can't make a diagonal trunk line work, I suggest you use the center line (planer-workbench-tablesaw-router table) as the single main trunk, and Y off of that trunk with short sections of pipe to get to the bandsaw and the jointer. This option would be even better if you could move the DC "south" along the wall so the main trunk can feed the DC without going through that first 90-degree elbow.

Good luck! -- Paul

Cary Swoveland
04-03-2007, 2:11 AM
Richard,

I'm concerned that, after you have put a lot of time and money into building a DC system, you're going to be disappointed with the results. You've started with the choice of dust collector, which really can't be selected until you've determined your DC layout and CFM requirements, and calculated static pressures. It's a little like buying a pickup truck and trailer, and asking what type of hitch you need to pull the trailer. It could be that your truck is just not big enough to pull the trailer, regardless of the choice of hitch.

You need to educate yourself about DC systems, and there is a quite a bit to learn. Fortunately, there is a lot of useful information on the internet. A good starting place is http://www.oneida-air.com/design/main.htm .

For a shop the size of yours, I think you'll need a cyclone DC that has at least 2hp, and ducting from the cyclone that is at least 6" in diameter (with 3hp and 7" or 8" being better).

I don't think the efficiency of the Delta DC you bought compares very favorable with that of a quality 2hp cyclone (e.g., Oneida or ClearVue). Consequently, I don't think the Delta is going to work in your app. The Delta might be OK if connected directly to nearby machines, but I just don't think it has the power to pull air through a network of flex hose, elbows and straight pipe, even if the network is properly-sized.

I think you have two basic choices. The first is to keep the Delta unit close to the machines it serves, and have a minimal DC network. This means you'll have to either buy additional DC's for distant machines, or move the Delta unit around the shop. The second choice is to have a shop-wide DC system, in which case I think you'll need a 2 or 3 hp cyclone.

If, after you've researched the subject, you are uncomfortable designing your own system, consider having Oneida-Air design it for you. I think they do it for free if you buy a 3+ hp system from them; otherwise, you can pay for the service. That's what I did when I bought a 2hp cylone and ducting from them about three years ago. (It's OK, but I regret not having bought their 3hp cyclone.) As it turned out, I completely revised Oneida's plan, but it was very helpful to have it as a starting point.

Cary

Rob Platt
03-30-2008, 11:13 PM
Richard - I've got a Delta 50-760 also, and for now have just taken it from tool to tool. I have thought about a couple of permanent runs in my shop, and have the same dilemma with the 4" vs 5" vs 6" thing, given the inlet size of this DC.

What did you end up doing, and how is it working out?

Thanks,

Rob

Dave MacArthur
03-31-2008, 2:04 AM
Richard, I 100% agree with Cary Swoveland up above. I also have the Delta 50-760, and the sad truth is that this machine is just not powerful enough to be a central system--that's why they put a 4' tube on it and made it mobile.

The recent FWW review on 1.5 HP DC rated it the #1 version, but also showed that it's maximum length of run to still meet minimum CFM and static pressure nums was around 6' of flex tube.

I highly recommend you go to Mr. Bill Pentz' site and read up on the engineering / calculating side of this, as the TUBES and PIPING is actually sometimes the most expensive part of it... and you really need to know the right nums before you even begin designing the tubes.
http://billpentz.com//woodworking/cyclone/index.cfm

Richard and Rob both-- the 6" tube will be better than going with 5", even though the inlet is 5". A short neck-down (the 5" inlet) gives much much less static and CFM drop than a length of the same size--running 6" is much better if you're trying to make a longer run than the machine is really designed for, EVEN THOUGH it has that 5" inlet for just a few inches.

Good luck! I really wish there WAS a magic answer that let a 1.5 HP DC do central DC work, as I have the same one.... but if there was, no one would buy a cyclone.

Regards, Dave

Scott Vigder
03-31-2008, 7:22 AM
With all due respect to the previous posts, I also have the 50-760. I have about 30 feet of solid tubing with flexible 4" branches to the TS, BS, router table, jointer, CSMS, and a flexible branch for scooping chips from the mortiser, drill press, drum sander or planer. I have a chip separator as well.

I have blastgates to control the various arms of the octopus, as well as a remote control.

The system works quite well. I have to empty the chip separator can when it gets about 2/3 full. I must vacuum out the inside of the filter bag three or four times a year to keep the air flowing.

Aside from a 2 1/2" reducer line to the router table, none of my branches use more than 3-4 feet of flexible tubing from the main trunk to the respective tool.

It's a bit of a pain having to modulate the blastgates, and I occasionally leave the remote at the other end of the setup, but I have not had any problems from lack of suction at any machine.

I wrapped all the junctions with a flexible tape that completely sealed the connection points. I cannot remember the brand name off hand but I sure remember it was about $12 for a single roll of 3" wide tape.

I would estimate that I have invested between $100- $150 in the "octopus" which does not include the cost of the Delta 50-760.

Finally, I will admit that I am in the process of slowly replacing the plastic blastgates with metal ones. The plastic tends to warp and twist and separate, and even with the sealer tape around the housing they don't seem to last more than a year.

Good luck with your design!

Phil Thien
03-31-2008, 8:31 AM
+1 what Scott says above, I think there are quite a few shops using 50-760 DC's as a central dust collector, piped with 4" PVC.

If the various Dylos tests have proven anything, it is that a big cyclone isn't the answer to fine dust collection. Plenty of shops out there with big cyclones and 6" ducting found a huge spike in fines when cutting wood using the Dylos meter. I believe the single biggest improvements comes from better hoods (like a blade-guard connection). There were at least a couple of shops using a blade-guard connection to a single-stage DC that outperformed shops with large cyclones.

That being said, I believe it is perfectly satisfactory to use your 50-760 to collect chips using a suitably designed network, and later add an air filter to control the fines that escape your DC system.

Matt Day
03-31-2008, 9:08 AM
Another +1 to Scott's reply. My 50-760 works just fine with blast gates. I only run about 12' of 4", but I'd think that two or even three times that length would still suck up the chips.

Quesne Ouaques
03-31-2008, 12:27 PM
I am in agreement with Scott. With all due respect to those who say otherwise, I can verify from experience that the 50-760 is an absolutely adequate central DC for a shop of this size. It is an excellent choice IMHO, requiring very little compromise between performance, size, cost and decibels.

My shop is 30' x 15' with a stationary 50-760 pulling from 6" mains and 4" drops. As an example, my 13 inch planer sits at the end of a 17 foot duct-run from the DC intake, and it gets cleared as neat as a pin. I chose 6" snap-lock for the mains after reading Sandor's "Dust Collection" book.

Due to some concrete "rafters" in my basement, I was not able to pass a diagonal main, so I used a layout nearly identical to the one you have in mind, Richard. My DC unit is near the bottom of a "horseshoe" layout, with 6" mains running up each side of my shop. I also have an auxiliary main running up and over the table for fine sanding dust pickup and other stuff.

FWIW, here is a to-scale Sketchup diagram of my shop with the DC unit and all of my tool stations. I used it for planning and research and it came in very handy:

http://74.94.15.133/Photos/AfricaPhotos.nsf/08DC146C2DB8D3EE8525720C000CE543/E977968A9E0C687B8525741D0056DE21?OpenDocument

Also, I chatted with some folks about my proposed setup in some previous posts:

http://sawmillcreek.org/showthread.php?p=783988#poststop

http://sawmillcreek.org/showthread.php?p=758664#poststop

http://www.sawmillcreek.org/showthread.php?t=63798

Brandon Shew
03-31-2008, 12:38 PM
Richard,

For a shop the size of yours, I think you'll need a cyclone DC that has at least 2hp, and ducting from the cyclone that is at least 6" in diameter (with 3hp and 7" or 8" being better).

I don't think the efficiency of the Delta DC you bought compares very favorable with that of a quality 2hp cyclone (e.g., Oneida or ClearVue). Consequently, I don't think the Delta is going to work in your app. The Delta might be OK if connected directly to nearby machines, but I just don't think it has the power to pull air through a network of flex hose, elbows and straight pipe, even if the network is properly-sized.


I was thinking the same thing.

As much as I hate to say it, you'll have to roll the Delta around for maximum efficiency. I'm speaking from experience. I have a 1 1/2 HP dust collector mounted stationary in my 12' x 16' shop. I have only one leg on it that feeds to the center of my workshop. Whenever I use a tool, I roll it to the center of the shop and connect the hose to it.

On that one leg is about 8' of rigid pipe, 8' of flex hose and two 45's on it. I'm working fine now, but if I had any more pipe, or any more 45's or 90's then I wouldn't be getting the collection that I need to run my jointer, 12" planer, or contractor's saw. You are looking at 20+ feet of rigid pipe from that back corner to some of those machines.

FWW article from last year indicates that in order to maintain 800 CFM and 4000 linear fpm (are these Pentz specs?), this is what you can use w/ the following.

1 1/2 HP, Single Stage Collector - 4' flex hose

2 HP, Single Stage Collector -18' flex hose, or 24 feet rigid pipe, one elbow, one y, and 6' flex hose.

2 HP, 2 Stage Cyclone - 68' rigid pipe, 1 elbow, 1 y, and 6' flex hose.

Based on this, I'm not getting 800 cfm/4000 linear fpm with my setup on a 1 1/2, and my setup works pretty good. I'm guessing that I am in the 500-600 range. With runs as long as yours, that Delta isn't going to cut it as a stationary machine. You may have better luck if you center it in the shop, but even then...

Dave MacArthur
03-31-2008, 1:55 PM
Last night I spent 6 hours re-reading every post by Bill Pentz on this forum going back 2 years, and every thread from start to finish with a post by him in it. A lot of info. Here are some basic thoughts that jump out at me, which apply to this thread:
1. Any DC that will do 350 CFM will make you happy with VISIBLE chip and dust collection--that means any 1.5 HP mobile, even on long runs. Anyone hooking one up and looking at it will post "does a great job!", which it does for large particles, keeps shop clean.
2. The primary danger to health is not from any of the visible stuff. It is from invisible sub-micron particles and fines--looking at a clean shop or a Delta 50-760 running on 50 feet of network which seems to pull all the dust and chips does not supply much valid data on whether it's working or not for the health danger aspects.
3. Control of the sub micron "fines" requires better dust hoods than come with most tools, combined with much higher CFM (800-1000) than that required to just look great on sawdust (350)-- you must move big volumes of air to get those invisible fines.
4. Even after successful capture via good hoods and high CFM, you still must get those fines out of the shop air. This means extremely efficient filtering combined with better than normal cyclone... or exhausting outside! Here is where all the work by Phil Thien and the Dylos dust meter folks is really paying off--answering the questions about "even WITH all this expensive stuff, is it getting rid of the dust??". As Phil says, the answer may be NO, if you're recirculating the air back into the shop and you're not running uber-efficient filter... which apparently most cyclones fail to do, when actually tested in-shop.
5. The answer has more to do with dust hoods for efficient collection, combined with exhausting outside and moving air through the shop with open windows/doors and a fan, than it does with trying to filter the stuff out with high cost cyclones and filters--all that is only necessary if you just CAN'T exhaust outside and must return that air.
6. A 50-760 (like I myself have) MIGHT do the trick, but there are a lot of things required which weren't addressed-- better hoods, machine outside, exhausting outside. A 50-760 sitting in the corner of your shop? All 6 hours of reading last night confirmed that this would not remove the health-dangerous fines.

Must run, I recommend reading Phil's dust measurement threads and Pentz threads.
Good luck!

Pat Germain
03-31-2008, 2:06 PM
I also have a Delta 50-760 and it works great with two 6' sections of flex tube. I sometimes accidentally forget to close the blast gate on my floor sweep, connected via another piec of flex hose, and it still works great. (I'm aware I should have a separator between the floor sweep and the DC, but I haven't got around to it yet.)

I don't want to start a conflict here, but I don't buy what Bill Pentz spews. That guy can list all the numbers he wants. The bottom line is his advice is extreme overkill for every situation. I'm wondering if he's got some kind of ulterior motive and what it might be. Anyone that anal shouldn't be working around wood dust at all. Just my take.

Michael McCoy
03-31-2008, 2:33 PM
Richard,
You sound like me several years ago and probably several others that have read this thread. I bought a DC and then spent about 4 months trying to match all the info with what I had room and expectations for. In the end I wound up running a simple PVC S&D line with Y's and short flex runs to individual machines. I've moved twice since then and still have basically the same setup except I added a trash can seperator which also increases drag and decreases DC efficiency. Is it good or even average? I doubt it but I usually work with fans moving air and double doors open to the outside. No doubt that I could easily improve my setup but it works for me and I'm the only one I need to please.

David Parker
03-31-2008, 3:01 PM
I'm planning on getting the Delta 50-760 due to it's compact size and two excellent reviews of its performance. Based on the charts in the recent Wood magazine review of dust collectors, the Delta can maintain well over 800 cfm of airflow within 5" ducts if static pressure (SP) losses are less than 4-5 inches of water.

5" smooth ducting gives 0.055 inches of loss per foot. A 45 degree bend adds 0.25 inches and a 90 degree bend adds 0.5 inches of SP loss. Flexible 5" ducting gives three times the SP loss (0.165 inches per foot). In a typical installation with three 90 degree turns and 4 feet of flexible 4" duct for machine connection, you can have up to 40 feet of smooth 5" ducting and still maintain 800 cfm.

For 4" ducting, the Delta peaks out at 700 cfm with up to 7 inches of SP loss. 4" smooth ducting gives 0.07 inches of SP loss per foot. A 45 degree bend adds 0.21 inches and a 90 degree bend adds 0.42 inches of additional SP loss. Flexible 4" ducting gives three times the SP loss (0.21 inches per foot). In a typical installation, where you would have all flexible 4" ducting with two 90 degree turns, you can have up to 20 feet of flexible 4" ducting and maintain 700 cfm.

They did not test the Delta with 6 inch ducting, but it should give results similar to the 5", except that you should make sure your cfm never drops below 700 or you may run into problems with chip fallout from the airstream. 6" smooth ducting gives you 0.045 inches of SP loss per foot. A 45 degree bend adds 0.27 inches and a 90 degree bend adds 0.54 inches of additional SP loss. Flexible 6" ducting has 0.135 loss per foot.

Looking at the curves, I see that the Delta's airflow drops off rapidly once you exceed these maximum SP losses, whereas most other machines slowly drop their cfm with rising SP loss. The Delta design just happens to work very well with 4 and 5 inch ducting provided you don't go above 5 to 7 inches of static pressure loss. Yes, the Delta 50-760 will fit my needs very nicely in my 12x15 shop. My short runs should allow the extra static pressure loss of a separator in front of the Delta.

Dave

Travis Gauger
03-31-2008, 3:17 PM
I think DC performance is relative. Bill Pentz is very knowledgeable and knows his stuff. He is also very accurate with his recommendations says my resources at Fox Valley Clean Air Corp. FVCAC came and did some tests for me awhile back. Happen to have a really good friend that works for them and got the testing done for ... Beer basically. The point is that there is a big difference between what different people consider effective DC. Some people don't want to sweep up after using the planer, others want to have a sterile environment to work in.
I too have a 1.5HP DC and use it with great success as a monument in the shop. Mine is a Jet with a canister filter on it. My shop is 22' X 26' and I have a total of 140' of 6" snaplock. That's just counting my straight pipe pieces. Not counting any drops, flex tube, turns, etc. I have great collection of chips. My fine dust collection is non exsistent. In our tests with FVCAC, we found that there was no change in fine particulate emissions for my saw with a 6" or a 4" connection hooked to it. The test was done while cutting 3/4" MDF on my unisaw. The CFM's at my saw during the test went from the 380 range with 4" to 725 range with 6".
At the time we were playing with these tests, My Father was in the process of moving his shop. He, a proud owner of a 5HP Onieda cyclone, started to explain the whole pitch he once got from a salesman. So we decided to put it to the test too. We brought that behemouth of a machine over and ran a 10' piece of 6" flex to the TS. We ran our tests again and got virtually the same results. More CFM, but the same results. The problem wasn't the DC, it was the Saw.
After about 3 months of weekend drinking, I mean testing, we concluded that unless I was ready to completely start redesigning and building my tools, it was a null point. We ran tests on the big cyclone and the small DC of mine and only found that unless you have a need to suck from 3 or 4 tools at the same time, the tool was the restrictive part of the equation.
I ended up making an air scrubber after a trip to the scrap yard that can change my air in the shop 8X an hour through HEPA filters. That combined with my 1.5HP DC is working great for me. My $.02

Pat Germain
03-31-2008, 3:31 PM
I agree Bill Pentz knows his stuff and he's just trying to help. Sorry, I guess I'm a little punchy on the DC subject. It just seems many DC threads go something like this...

Cletus: I have a 20' X 20' shop and I'm using a Pratt & Whitney J58 I salvaged from a retired SR-71 Blackbird as my dust collector. I'm not sure that will be adequate.

Lester: Hey Cletus, according to Bill Pentz, the 32,000 pounds of thrust you'll get from the J58 isn't quite adequate for a 20' X 20' shop. Perhaps if you run the J58 in full afterburner all the time, it might work. I'd recommend buying the other J58 from that SR-71 and running them both in tandem. Just to be sure, put both in full afterburner to get every bit of wood dust. Of course, you'll have to run 1/8" titanium-walled tubing for your ductwork lest it collapse from the negative pressure you'll be generating in your shop.

Leon: Actually, I had a discussion with Bill Pentz the other night and he relayed a story about a neighbor running dual J58's for his shop. Bill wasn't convinced this was adequate and suggested the GE turbofans currently being manufactured for the A-380. Apparently, the CFM they generate will just barely ensure proper suction for a TS and a jointer. Of course, if you add a floor sweep, better run three of those turbofans...

Rick Thom
03-31-2008, 3:37 PM
Dave's remark wrt separator likely ok is significant for those contemplating a 50-760 because they have very small chip collection bags (6 cu. ft?), about 1/2 the size of most other full sized dcs. A jointer or planer can fill it in a few minutes and it is a nuisance to empty. The dc works more efficiently if the bag is less than @2/3 full so if you van intercept the large stuff from the planer/jointer life will be better.
I also have a Wynn pleated cartridge rather than the wool bag. Great addition if it actually meets specs, is only @ 24" high and costs @ $120. I see some dust collecting on the pleats so I will have to blow it out.

Wilbur Pan
03-31-2008, 3:50 PM
Anyone that anal shouldn't be working around wood dust at all. Just my take.

Whatever your feeling on Bill, this is a curious way of putting it, as the one common characteristic of the best woodworkers I've seen is a particular attention to detail.

Pat Germain
03-31-2008, 4:00 PM
Good point, Wilbur. Attention to detail is indeed important to be a good woodworker. I'm just thinking if someone is deathly afraid of inhaling any wood dust, perhaps woodworking isn't the best hobby. Personally, I use my DC whenever possible and wear a good resperator. Turning a woodworking shop into an aerospace clean room seems a bit overboard to me.

Then again, I guess it's important to feel comfortable with one's shop. I recall recently reading a post about a guy who painstakingly levelled every machine in his basement shop. While this probably isn't necessary, if it allowed him to move on to other things without worrying about his machines being level, I can understand it.

Quesne Ouaques
03-31-2008, 5:35 PM
A 50-760 (like I myself have) MIGHT do the trick, but there are a lot of things required which weren't addressed-- better hoods, machine outside, exhausting outside. A 50-760 sitting in the corner of your shop? All 6 hours of reading last night confirmed that this would not remove the health-dangerous fines.

Very glad that Dave made this point and I would like to add a comment based on my previous post.

While I am very, very happy with the performance of my 50-760 for both chip collection and much of the fine dust control, health considerations for me and my family are very important. Before purchasing the 50-760, I read Sandor's book and reviewed Bill Pentz's site in great detail.

As a result of what I learned, I decided to also purchase a Penn State AC-1000 air cleaner unit, and to adopt some other practices to complement my dust collector. My point is that the DC unit is only one part of my own dust control strategy.

For my strategy, I do all of the following:

1) I always use the central DC unit whenever possible. Optionally, I also use my 5.5 HP ShopVac with a HEPA filter and fine dust filter bag;
2) I wear a dust mask whenever I create fine dust that may not get picked up at DC hood;
3) I vent my shop air directly to the outside when the weather permits; and
4) I always run the AC-1000 regularly when I leave the shop after creating any fine dust.

Since I started to seriously follow this overall DC strategy, I have noticed a huge difference in shop cleanliness and my own dust sensitivity.

Art Mann
03-31-2008, 9:31 PM
Whatever your feeling on Bill, this is a curious way of putting it, as the one common characteristic of the best woodworkers I've seen is a particular attention to detail.

I don't think Bill Pentz's approach to dust collection is related to being a stickler for detail, although he may be that. His motivation is that he has had severe respiratory problems that, if I remember correctly, were related to his military service. From his life experience, he has developed the opinion that any amount of wood dust is hazardous and potentially deadly. I think his personal health problems have shaped his thinking to the point that he has past the world of cautious and entered the world of paranoid. His website does have some excellent practical DC design information though.

Pat Germain
03-31-2008, 10:45 PM
^^ Based on what I've read here, on other forums and on the Bill Pentz web site, I agree with you, Art.

For those who admire Bill Pentz and his work, I respect that. Sorry if I sound negative. I really don't mean to bust on Bill Pentz. I just have a different point of view.

Dave MacArthur
04-01-2008, 3:16 AM
Richard, I think Dave Parker up above has some excellent numbers for you--in fact, his highlighting of the much greater length of 6" or 5" metal piping which will keep my 1.5 HP DC running good CFM, has got me trying to re-design my shop layout similar to your OP! ;)

Pat, without disrespect, I have to say that you appear to only focus on the painful minutia on Bill's site, those costly and painful details that are ONLY REQUIRED when you have skipped the first through sixth lines of "defense", or decide you still want DC better, usually involving sub micron stuff, invisible particles, and probabilities.

Here's your quote up above: "Personally, I use my DC whenever possible and wear a good resperator." Strange, this seems to me to be exactly what I hear Bill Pentz and others saying as the #1 advice. No one is actually arguing with you, Pat... you're just frustrated as all of us are because reaching TOTAL dust control to alleviate our health fears is so impossible and painful. Here's what Bill Pentz actually says, in what IMO is his #1 most useful post ever:


My recommendations:

Budget & Once in a While Woodworkers:
(Except those who work indoors or in basements).
Buy and use a good 3M 7500 dual cartridge mask fit to your size face. If you are a turner, have a thick beard, or have sensitivities the Trend Airshield seems to be the best powered respirator available for its price. This mask goes on before you start making fine dust and stays on until you have thoroughly cleaned out your shop. If you come back on following days before you clean up, you need to wear the mask.
Put and consistently use a big fan in an open doorway. That fan goes on and stays on for the rest of the day anytime you make fine dust.
At least monthly open all up wide, put on your respirator mask, turn on the big fan in the doorway, and thoroughly clean out your shop. I’ve used both my air compressor and leaf blower to do this. Then let the shop air settle at least overnight before taking off the mask if you stay in the shop to work.
If a door connects your home to your shop put a bathroom vent fan in your shop that turns on when you turn on your shop lights. This will create enough negative pressure that you should not have big blasts of dust going into your home.
Wear at least an apron and if the dust cloud is going to be thick seriously consider a jumper, scarf and hat that stays in the garage.
Use any decent 1.5 to 2 hp dust collector with a 10’ long 6” diameter flex hose going right to your tools. Even if you neck down right at your dust collector and your tool you will still get better airflow with that bigger pipe.Now I'm sorry... but THAT is not the advice of a paranoid anal retentive, nor someone who has lost sight of reality. I feel that you are for the most part erecting what in debate is called a "straw man"--putting your own words upon someone else in a way to make them sound silly, then knocking them down on that basis. Do you know, in an entire page of advice, numbered from 1 (most important) on, only the very very last line does Mr. Pentz say, "Cyclone – To minimize our filtering overhead we need a good fine dust separating cyclone that both moves enough air to collect the fine dust as it is made and provides a very light dust loading on our filters."

Folks log on to SMC and use their valuable time reading threads like these because they are concerned. When folks take time to do research, try ideas, test air quality--such as the great post above by Dave on static pressures for the 50-760, or Phil Thien on trashcan separators, or everyone who bought an expensive dustmeter and is out there getting DATA instead of opinions--we should be careful to not shoot the messenger, when we find they carry an uncomfortable message.

While I've mentioned Bill Pentz above, I in no way would refer to him as some kind of guru--in fact, I find threads by other skeptics who yet go out to do some testing themselves to be more pertinent to me. Phil Thien's pages, all the threads on dust hoods, folks who build their own cyclones for very low cost, guys who eek the last bit of CFM from that 50-760 or show me a way to make it work better for me.

Here is the post from Mr Pentz I referred to above, which I think is just a great "synopsis" of everything he's written, but put in a big-picture so we remember where it all fits:
http://www.sawmillcreek.org/showpost.php?p=736339&postcount=89

My best regards,
Dave

Dave MacArthur
04-01-2008, 3:33 AM
If I ruffled any feathers above, I'd like to apologize--we all get fired up easily on Dust Collection for some reason... it's almost as bad as politics, religion, or festool! ;)

Richard, I had some thoughts which may be pertinent for you:
1. Where are you located? Can you exhaust outside? If so, I have some posts/threads bookmarked where the CFM and performance of the 50-760 is much increased by removing the filter bag off the top, and either placing the machine outside or ducting it out.

http://www.sawmillcreek.org/showthread.php?t=72781
http://www.sawmillcreek.org/showthread.php?t=71184

2. Can you make use of an attic above? Several folks have put their DC up above the shop in an attic, or at least part of it (some had the fallout container in the shop below. This has opened up much shorter runs for them, much quieter shop, and built-in soundproofing for folks hearing it from outside.
http://www.sawmillcreek.org/showthread.php?t=48708

Pat Germain
04-01-2008, 11:07 AM
No disrespect taken or ruffled feathers here, Dave. The Bill Pentz quote you posted sounds very reasonable. Other quotes I've seen I would say are a bit beyond reason. I think we sometimes get to the point of absurdity on the subject of dust collection and I was responding in kind.

Brandon Shew
04-01-2008, 12:43 PM
I'm planning on getting the Delta 50-760 due to it's compact size and two excellent reviews of its performance. Based on the charts in the recent Wood magazine review of dust collectors, the Delta can maintain well over 800 cfm of airflow within 5" ducts if static pressure (SP) losses are less than 4-5 inches of water.

5" smooth ducting gives 0.055 inches of loss per foot. A 45 degree bend adds 0.25 inches and a 90 degree bend adds 0.5 inches of SP loss. Flexible 5" ducting gives three times the SP loss (0.165 inches per foot). In a typical installation with three 90 degree turns and 4 feet of flexible 4" duct for machine connection, you can have up to 40 feet of smooth 5" ducting and still maintain 800 cfm.

For 4" ducting, the Delta peaks out at 700 cfm with up to 7 inches of SP loss. 4" smooth ducting gives 0.07 inches of SP loss per foot. A 45 degree bend adds 0.21 inches and a 90 degree bend adds 0.42 inches of additional SP loss. Flexible 4" ducting gives three times the SP loss (0.21 inches per foot). In a typical installation, where you would have all flexible 4" ducting with two 90 degree turns, you can have up to 20 feet of flexible 4" ducting and maintain 700 cfm.

They did not test the Delta with 6 inch ducting, but it should give results similar to the 5", except that you should make sure your cfm never drops below 700 or you may run into problems with chip fallout from the airstream. 6" smooth ducting gives you 0.045 inches of SP loss per foot. A 45 degree bend adds 0.27 inches and a 90 degree bend adds 0.54 inches of additional SP loss. Flexible 6" ducting has 0.135 loss per foot.

Looking at the curves, I see that the Delta's airflow drops off rapidly once you exceed these maximum SP losses, whereas most other machines slowly drop their cfm with rising SP loss. The Delta design just happens to work very well with 4 and 5 inch ducting provided you don't go above 5 to 7 inches of static pressure loss. Yes, the Delta 50-760 will fit my needs very nicely in my 12x15 shop. My short runs should allow the extra static pressure loss of a separator in front of the Delta.

Dave

Based on the OPs diagram, I roughly estimated 45' rigid pipe (5' up the wall, 5' over to the long run, 30' run, 5' down), 2-90's, 1 wye and 3' flex hose on the longest run to the router (not counting the 45 Y at the collector) Based on your SP parameters that's 4.22" SP using 5" pipe. Based on Bill Pentz's SP calculator and factoring in the sub 5 micron bag, I come up with 4.56" SP - both pretty close. I haven't seen the discussed fan curve, but I would have a hard time believing that the Delta could maintain 800 CFM at 4.5" SP. PSI's 2 HP cyclone w/ 12" impeller is closer to 450 CFM at that SP.

As others have said, he'd be better off putting that machine in the middle of his shop if he hopes to leave it in place.

Shawn Honeychurch
04-01-2008, 1:55 PM
If I ruffled any feathers above, I'd like to apologize--we all get fired up easily on Dust Collection for some reason... it's almost as bad as politics, religion, or festool! ;)

Heck after reading some of the posts on the Creek I had assumed that Festool was a religion. ;)

glenn bradley
04-01-2008, 2:00 PM
Have you considered eliminating some of those right angles and using 45* instead?

Ken Ganshirt
04-01-2008, 6:27 PM
--we all get fired up easily on Dust Collection for some reason... it's almost as bad as politics, religion, or festool! ;)

That's because until very recently dust collection had to be treated pretty much as a religion if your goal was respiratory protection rather than just a visibly clean workspace. There was no way to measure the effectiveness of anything we did so we had to take it totally on faith.

With the availability of the Dylos particle counter we can now do some comparative measurement to see if any change we make has the desired effect. It's far from perfect but at least we aren't flying blind any more.

Festool isn't really a religion, unless you've got a lot of money. For those of us on limited budgets it's just a fairy tale ... ;)

...ken...