I have been trying out my new 15″ Grizzley planer. I finally got it aligned but now I discover that I have a dust collection problem. My DC system usies 4″ flexible ducting and I have one main run about 30 feet with 3 drops. The total run to the planer is about 34 feet. Up til now the dust collection from the other power tools (BS & Jointer) has been adequate. But when I use the planer (at the far end of the duct work) I can’t seem to get enough vacuume power to take away the chips. I felt the end of the open duct and felt only a slight pull from the DC system. Is 34 feet simply too long for my DC system? Since I have only used the DC probably less than 2 hors total since I bought it (Grizzley) I am afraid I will have to sell it and buy a larger DC system, which presents all sorts of “where do I put it” problems. Any DC PhDs out there?
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Replies
Hi Jack,
I don't have a PhD but a couple of ideas. You may be able to increase the amount of suction by decreasing the diameter of the collection tubing to the planer. You can by adapters that'll decreease from 4" to 3" or even 2". The other is one of my favorites...calling customer service at grizzly. I am sure thay have had this question many times and may have some solutions. Hope that is helpful. Blessings-Eric
"4" flexible ducting and I have one main run about 30 feet " This part of the description caught my attention. I'm no expert (just got my DC, no ducting yet) but that flexible ducting cause alot of decrease in efficiency over long runs. I'm guessing you need to put in solid ducting (PVC or metal) for your main run, and have as little flexible hose as possible.
One source of info: Bill Pentz's DC web site, which has been recommended to me by several other woodworkers. Here is the link to the ducting section. He recommends PVC 2729 Sewer and Drain (S&D) Pipe for hobby use, saying that it's less expensive than Schedule 40 PVC and that it's "much stronger than metal pipe, doesn't leak like HVAC pipe, and has a much lower coefficient of friction than even spiral metal ductwork."
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another proud member of the "I Rocked With ToolDoc Club" .... :>)
RE:dust collection
Most systems require gates at all machines to get max suction where needed
"Most systems require gates at all machines to get max suction where needed." Absolutely. I was so aghast at all that flexible ducting, I spaced on blast gates.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Thanks for the tip. If I use PVC for the main DC overhead portion, will it require gluing sections together or can you just slip fit the pipes together?
Far as I know, they're just slip fit, but this DC stuff is pretty new to me.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Jackall,
Best is to just slip them together, drill a small hole at the joint and screw a self tapping screw, which keeps the joint from pulling loose. That way, if you want to remove, change, or suck up a rag, you can quickly take apart and put back together.
I'm planning to follow Bill Pentz's advice and use PVC 2729 S&D pipe for my main ducting. He mentions that it is available with built-in seals: "They only cost a little more and make tight joints that normally don't need anything more to hold them in place." Anyone have experience with it?forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
FG is that 6" diameter? I'm assuming that you can get "ys" and "Ts" that are 6" and reduce to 4" Who's your supplier? Do HD/Lowes carry the big pvc stuff?Mark
Measure it with a micrometer, mark it with chalk, cut it with an ax.
Hi Mark, I haven't started shopping for it yet -- no time at present to put it in. In the "small cyclone thread?" thread, Tom says he found 6" 2729 PVC through a "more rural" plumbing supply company, assuming they must use it for agricultural applications.
Whether my main duct(s) will be 4" or 6" will depend on how the machinery ends up getting sitchiated. If it's all in one direction down the wall and in the center, I'll use 6" for the main. If I split to go down 2 walls in opposite directions, I'll use 4" for the mains. That's as far as I've thought!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Forest,
Using a 4" for a main run, anything more than 6' long is not a good idea, even if you have a small say around 1000 Cfm collector. You lose performance very quickly.
Post your shop layout, with collector here, showing the runs, and it will be a pleasure to size them for you with the expected CFM calculations at each point. I would need the size of collector, the length of the runs and how many bends etc.
I've had a hard time finding 6" diameter 2729 around here (SE WI). The advantages of 2729 over spiral pipe are price, and that depends on where you are. Here is a source of 6" pipe and fittings. Notice the big price jump for the 6" size:
http://www.usplastic.com/catalog/category.asp?catalog%5Fname=USPlastic&category%5Fname=8762&Page=1
More than 2x - ouch...
Measure it with a micrometer, mark it with chalk, cut it with an ax.
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According to my primary source (Penz's site) the PVC also has a much lower coefficient of friction than the sprial pipe, making for more efficient collection, right?
from this page: http://billpentz.com/woodworking/cyclone/Ducting.cfm#Pipe
That caught my eye! especially with a lowly 1.5HP collector, need all the efficient pipe I can get.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Edited 5/10/2005 8:24 pm ET by forestgirl
Hi,
I hope people don't mind me barging in here but this thread is exactly what I need. I am finally putting in a DC system which I have delayed only because I can't figure the things out. Do I want a cyclone or the"other type" ? How do I calculate how much horsepower I need? Things like that. I went through the archives and a lot of that is taken as a given. I have a basement shop with all the usual machines of the sport,(Table saw, jointer, bandsaw, router station, portable planer). I am going to run the duct outside and place the dust collector in a small shed abutting the house. Therefore I needn't be concerned about particle size and filters as much as if the filter were still inside. I am running about 25 feet of 6ince S and D pipe over head in the basement. I am not particularly concerned with separating the "flour" from the chips or the wheat from the chafe for that matter. It all gets dumped in the woods anyway.
Thanks,
Have you visite the Bill Pentz site liste in FG's post. There is tons of information to sort through and it should answer your questions.Mark
Measure it with a micrometer, mark it with chalk, cut it with an ax.
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Here's a link to the "Deciding Needs" part of Pent'z web site. Gather your patience, he's a bit wordy, but the info is worth it. Scroll past all the Announcements and get down to the nitty-gritty.
Also, you'll see a row of links -- wood-grained with blue headings. The ones I've found most helpful so far are Requirements, Equipment and Ducting.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
I read through his website and there was a lot of great information. I think I am going to get either the Grizzly 4hp dust collector or the 3 hp cyclone dust collector. My only concern now is noise levels. While I am building an outside enclosure I don't know how noisy the thing will be. Since I do much of my woodworking in the evening I don't want to annoy the neighbors.
Much Thanks to all for their their help
Stewart
Stewart,
If you have the time to plan this properly, either do the research by buying some books, or get professional help, to design and calculate the system exactly to your needs. Putting the collector outside is an excellent idea, provided you can protect it from the elements and you don't scare the neighbors away. It's real easy to silence the machine by building an enclosure around it, using sound absorbing materials on the panels.
I use to work as a design Engineer, in the early 80's, designing dust collection systems in the fiber cement industry, and we use to design collection hoods and pipe sizing, so that the exact CFM requirments are delivered, at the right points, without the use of any blast gates. They were refered to as "balanced systems."
Personally, I have a 3 car garage, which is now full of woodworking machinery, with a dust collector installed. As this is temporary, rather than get out my old books and design properly, I just winged it, went to Home Depot, bought a lot of PVC pipe and installed the whole DC system by trial in error on a Sunday. Then I lost too much through the 4" pipes, so I winged it further and ran some more 4" pipes next to the first ones, to get the whole thing working OK on a Sunday. I can kick my own but for doing this every day and when we move to the ranch, I will calculate everything to the 4th decimal, before re-installing.
You might want to check out the Oneida site too. They offer free ductwork design service when you buy a system. They also have a new line of cyclones, the Dust Gorilla.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Thanks again,
I intend to use 6 inch PVC sewer and drain pipe as an overhead from the outside enclosure to the ceiling of my shop. I intend to also place my compressor in the enclosure as well. I find myself nailing brads by hand when I don't want hear the noise. I think the reason I have avoided the whole dust collection issue is the research and planning. It makes my head spin.
Stewart
"It makes my head spin. " I hear ya! $$ kept me down for quite awhile, since I was holding out for a cannister-design collector. When I finally got the DC (thanks to "Migraine" Brian!) I realized I'd just started.
Don't know if this would be of help, but Grizzly has a shop design program that enables you to move those big machines around on paper. Click here if interested.
Maybe tms will pitch in here. His was the shop where we had the Seattle Knots Fest. He has an Oneida cyclone and a big 3-phase compressor in a separate room from the shop. Ran lines all around his big shop, and the DC lines really suck!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
I put off getting into the dust collection issue as I felt it is a huge investment for something without any "fun factor". After all you don't get the same thrill from a dust collector that you get from a new lathe. However after I saw a discovery channel special on Pompeii with all the volcanic dust my wife said it looked like my shop and I wondered what I was doing to my lungs. Then I got hit with all the technical stuff. I did decide that Hp for Hp the cyclones were not the best value for me. I don't bother separating the whites from the yokes so I surely don't need to separate the chips from the flour. It is all going in the woods. I am buiding a shed next to my basement to house the 4hp grizzly DC and having my electrician move the switch to inside my shop. I am going to get a 8 inch sewer pipe, preferably not used, and run it from the DC along the ceiling. There will be 4 or 6 inch pipes coming off that to the machines with a blast gate at each junction. A floor sweep at one end and I think I am set. If I am real amitious I will ground the whole thing with some copper pipe. If my luck holds I won't find that the minute I finish the whole set up I change jobs and have to move.
Stewart
Found this web page by a guy named Terry Hatfield -- shows his shop-made cyclone system and blast gates. forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
I viewed the website and like many others dedicated to the joy of dust collecting, these guys have way too much time on their hands. It does provide some useful designs however. Thanks,
"need all the efficient pipe I can get"I think you need as little as possible efficient pipe :-)M.
Measure it with a micrometer, mark it with chalk, cut it with an ax.
View Image
Forestgirl:Yes, the PVC is smoother, but the large radius curves, while available in both, are easier to find for the metal, so sometimes smaller radius turns are used in PVC, which can get rid of the advantage.If you want to judge the effect of such details as smoothness, curve radius, and shape of collection hood, take a look at this calculator:
http://www.freecalc.com/ductloss.htmIt is not needed for everything. Pentz put the critical parts of this in the "static calculator" on his website, but this will allow you to see how much the smoothness is buying you, and how that compares with turn radius and hood shape. (Punch line: hood shape makes more difference than you would think.)
Box stores don't carry larger than 4" but I have seen several Lowes that carry 5" S&D. I found a farm irrigation supplier that would order me any size with the appropriatew fittings. This stuff goes up to at least 12" diameter. There are plenty to fittings including wide or tight radius elbows. There are a number of thiniwall pvc manufactures out there and you should be able to find a dealer in your area. The cost was far less that metal pipe.
Doug
You can slip them together and use metal duct tape.....easily changed later. Aloha, Mike
That certainly seems like a good approach. Sometimes I wonder if the suction itself would draw the parts together and therefore you wouldn't need tape. Of course that would lessen the suction for the chips and I can't afford any losses. Thanks for the tip.
"Of course that would lessen the suction for the chips and I can't afford any losses." Why? Wouldn't you only lose suction if there were air leaks at the junctions?forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
My thinking was along the lines that certain things reduce the DC available suction at the tool, things like long runs of duct work. My first understanding of the general problem of suction losses was that once the long duct had been evacuated that the full suction of the DC would be available to the tool. However, I now understand that long duct work, curves, corragated surface inside the duct, etc. all act as continuous "draws" on the vacuume budget, not just at the beginning. That is why I considered the vacuume pressure used to draw the duct joints together would be another continuous "draw".
However, I could be wrong. I certainly am no expert on this topic.
Jack,
Flexible ducting, 4" x 30' feet long will kill most dust collectors. The ribbing in the pipe causes turbulence and over 30' you will cause so much static pressure loss, not much will remain.
You will have to either move the collector close to the planer, or install a 6" header as your main branch. You can do this with either PVC from your plumbing supply store or get some expensive metal ducting.
The previous advice to put in smaller piping will make matters even worse.
You want a velocity in your piping of between 3000 to 4000 feet per minute and your planer will need in the region of 700 cfm.
"or install a 6" header as your main branch"
Won't a larger diameter system actually decrease the vacuume?
No,
It actually works the other way around.
You do have to be carefull when going up in duct size that you collector has enough cfm to maintain the proper velocity in the duct. If he has a small collector 6" duct may be too large. Ideally you should plan your ducting before purchasing a collector and size the machine according to what the calculations determine is necessary.Tom
Douglasville, GA
Absolutely correct,
If you go below 3000 ft per minute, some of the heavier chips will block the pipe.
The formula is: Q = V x A
Where Q = volume of air moved in the pipe in CFM (Cubic feet per minute)
V = Velocity of the air (Feet per minute)
A = Cross section of the pipe. (Square feet)
To get A, use Pi x D squared/4 or Diameter x Diameter (inches) x 3.142 / 4/ 144
So, if his collector can pull 1000 cfm in the main branch of 6"
V = Q/A = 1000/(6 x 6 x 3.142/4/144) = 5092 feet per minute, and all will be well.
If this collector is connected to his planer only at the end of the line and he is pulling a nice 700CFM, with all the other blast gates closed he will be just dandy.....
My guess is that you'll have to do both ideas mentioned above: ie. move the planer closer to the collector and increase the duct size. Planers need a lot of air movement because the shavings are quite large.
I don't have a clue as to what type of collector you have or what your shop set up is like, but consider moving the collector to the center of the shop, if you can. This will reduce the duct run in half. 30 plus feet is a lot of ducting for a home shop collector.
Jack, please let us know what dust collector you have.
I see that the planer has a 4" dust port. That's the size ducting that should be attached to it, not any smaller.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Yes, a larger duct will allow you to pull more air, but the air will move slower in the duct and you might risk clogging. But there is something cheaper and simpler to try first. 4" smooth pipe will give you much less flow resistance than 4" flex, and it's a heck of a lot cheaper too. You should not need to pay more than $5 for a 10' section of 4" S&D PVC (also known as 2729). The 6" diameter of this is harder to find, and frequently 4 times as expensive.
Ideally, you would like 800 CFM (cubic feet per minute) collection at the machine. There is no way you can do this in a reasonable way with 4" duct. Here's why. What makes the air go through the duct is pressure difference. Your blower at one end decreases the pressure, so the air gets pushed through the tube. The more the pressure difference, the faster the air gets pushed. But some of the pressure difference is wasted in getting the air through the tube, and is therefore not available to push more air through. This loss is what people refer to as SP or static pressure needed to push the air through. It is complicated because it depends on the duct, and no how much air is going through. SP is measured (around here anyway) in inches of water. 1 atmosphere (14.7 psi) is about 30 feet of water, so we are talking about small pressures.
800 cfm through 30' of 4" flex duct would require 25" of water, well beyond the capacity of any small shop DC. A huge one might be able to handle 10". 400 CFM through 30' of 4" flex would cost about 6" of water, while 30' of smooth 4" pipe would cost about 3" of water, while 10' of that smooth pipe would cost 1" of water. This is not enough to tell how well your system your system would work, but it should pull about the same through 30' of smooth pipe as it does through 15' of flex.
The design of the collection hood can also make a big difference. A bare pipe end is improved by a flat flange around it, and a taper is better than that, with a bellmouth adding the least to the SP.
If you want to tweak your system, these are things to look at. If you want to be sure to have sufficient collection at each machine to meet specific recommendations, you want to start there and design your system, choosing the DC last to fit the system you come up with. Searching on this forum for posts by Bob Dodge will get you a long way, and will provide links to much helpful info. You will also notice that people do not all have the same opinions.
Oops! Search for Dodge's posts here: http://www.forums.woodnet.net
Edited 5/10/2005 1:08 pm ET by AlanS
Smooth wall tubing on your main pipe run helps air flow and minimizing the amout of ducting to machines that need lots of material pickup is good too. Have you considered having your DC supplier make a reccomendation for how to set up your system? They are usually helpful in this manner. Dont forget to have shutoffs closed on machines not in use while trying to pull maximum from your large waste producer and a cyclone in line right after the planer is very good accessory. You need probably 1100-1200 cfm on that DC it would seem to me. Lots of things to look at and more than a few ways to twek to get what you need. Aloha, Mike
Hi Jack, I have no idea of your individual circumstances,but, you might consider, moving the collector from one tool to the next. No pipeing,more suction, less labor. My shop is small, this works for me. Lood luck, Chuck Keller
Now you have infected my brain with your idea. My shop is very small also and I don't know if I can navigate that thing around the tools or not. I would not mind having to re-route the hose each time I change tools. Small price to pay for solving my problem.
"I would not mind having to re-route the hose each time I change tools." Mmmmmmm, boy I would mind. At least enough that I'd probably "skip it" often enough to dirty up the lungs. Sounds like you have a pretty nice shop with some good tools -- give 'em a good DC set-up to work with! :-) No need for a new DC probably, just decent ducting that doesn't waste the effort of the DC.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
I certainly hope that changing the duct-work to smooth pipe instead of my current flex tube stuff will solve my problem. But I only have a 500 CFM DC. The more I hear from the experts the more I'm thinking that it is too small for a planer even if it were hooked up directly to the tool. I have 2 problems in trying to upgrade to a larger DC system. First, I would be getting into 220v motors and 220 v service in my shop is maxed out already. (I only have a single 20 amp drop for 220 v). The second problem is that I simply don't have space for a larger system. I know this is the kind of problem that requires a great deal of imagination and maybe there is a floor-space solution but I haven't found it yet.
With a 500 cfm machine your best bet is to just connect directly to each machine, using the shortest piece of flex hose possible.
The losses in ducting, in laymen terms, is caused by the air in contact with the duct wall, being slowed down, as it touches the surface. So, you have air in the center of the pipe, at a higher velocity than the air at the outer radius. This causes turbulence, as the air in the pipe now starts swirling. In turn, this causes you to lose suction, as you are expending energy inside the pipe. The higher the velocity of the air, the more pronounced the effect. In conclusion, anything that restricts, such as joints, fittings, ribs on flex pipes, just adds to the problem.
It's the same thing in motor cars, today most designs go through the wind tunnel, to reduce air turbulence, improve fuel consumption and performance.
The dust collection junkies, will rephrase the above as follows:
Friction head = friction factor (Smoothness of pipe) x equivalent pipe length x velocity head.
The velocity head increases proportional to the square of your air velocity, so an increase in speed has the squared effect of increasing losses in your system. That's why correct pipe diameter is so important.
Thanks for the tutorial on air flow. I would not have a problem making a direct DC connection to the planer except I really don't have room for the DC on the shop floor. Right now it is positioned on the end of my L-shaped workbench. Floor space is at such a premium in my shop that I would not have room to bring it down off the workbench onto the floor.
500 CFM? Wow, that is small! The 220V thing is a non-issue, IMHO. Plenty of 110 systems out there with bigger capacity. But the space problem is a problem! Is it a footprint thing, a height constriction, or both?forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Looking at my catalogs, I find that to go to a larger model DC would violate my current height restriction because I have my DC sitting on my workbench in a nice convenient corner by the wall. All the larger models I have seen would be too tall to go on the workbench so I would have to find floor space - and that is a problem. I would be too embarassed to tell you the amount of open floor space I currently have in my garage (my shop). It is less than 3 digits in square feet. But I have lived with it for many years so I find it tolerable. The thing that really hurt was when I decided to get a modern table saw fence. The fence rails made the saw too wide to fit under my work table where it had always been stored. So I have to keep the TS out in the middle of the small space I used to have. If I could only talk my wife into keeping her car out in the driveway...oh well.
"I would be too embarassed to tell you the amount of open floor space...." Au contraire! You should be proud for making a tiny space work!
Penn State has a couple of mini-collectors that they rate 850 and 914 CFM. You might want to check them out. They're the style where the bag goes off to the side rather than the top of the blower. Theoretically, that CFM would cover even a table saw pretty well.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
I have not seen Penn State catalogs. Do they have a Web site?
Yes, Penn State's web site is:http://www.pennstateind.com
The two collectors I referred to are linked below:
The DC5The DC3-1M Note that you can get just the motor/blower.
I don't know how these would compare to other machines, but became aware of them when researching my own DC needs. forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Thanks for the info.
Mine is a 1200 cfm dust collctor and doesn't like to pull more than 25 ft on the level
i had it plumbed in but went back to a mobile state and move it around,it is a craftex 220 volt 3 hp motor with a double 4" inlet
I find if I try to plane to much with pine it plugs at the inlet on the screen to fan and causes wood chips get trapped in the wood coming out of the machine
Have had it for about 8 years and still happy wirh it
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