Author Topic: Dust Collection System  (Read 3350 times)

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Offline Climber39

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Dust Collection System
« on: April 18, 2020, 09:01 AM »
So I'm finally getting around to finishing the installation of the dust collection system in my home shop.  No more extension cords, shop vacs, or 5 gallon buckets full of sawdust. I'm starting on it later today.  Right off the bat,  I've run into an issue.  I've been told by several,  far more experienced people,  that have all told me to keep the ductwork as straight as possible,  and to use the largest diameter ductwork possible. So, if the 2 ports on my collector are both 4 inches, would it hurt the overall performance of the system if I were to use 5 inch ductwork and a reducer? In other words,  will in the performance suffer if the diameter of the ductwork exceeds that of the ports on the collector?
I'm planning on dismantling the dust collector,  and reassembling it in a different configuration. One that'll allow me to add a cyclone separator and effectively make it a 2-Stage. The ports on the separator are also 4 inches. 
I am fine with 4 inch ductwork. There's not a huge price difference  between 4 and 5 inch pvc. I just want to know if there's any benefit or problem with running ductwork that's larger than the ports on the collector and separator.  Any advice or experience anyone can share with me would be greatly appreciated. And if anyone has anything to say about grounding the dust collection system,  and whether it's actually necessary for a hobbyist weekend warrior's shop, I'd love to hear your thoughts. 

Thanks,  and everyone have a great weekend.



Offline SRSemenza

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Re: Dust Collection System
« Reply #1 on: April 18, 2020, 10:46 AM »
There are people on the forum that know way more about this than I do, but I am betting that 4" duct will do very well.  I use 4".   My longest run is a 10' hose (4") into 20' of 4" duct that has two 90 degree bends. 

The thing is that there are a bunch of factors involved besides the diameter ......................  power cfm of the unit, length of runs, filter, cyclone, etc. Those all effect the flow.

Do you have any 4" (even a hose) that you can use to do a little of your own testing?  EX - if a 4" hose works well in a less than optimal set up then the 4" duct should work better with a better set up. Doing that might answer your question to your own satisfaction without needing to become a dust collection engineer and go through a lot of unnecessary factoring and decision making.

Seth

Offline Cheese

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Re: Dust Collection System
« Reply #2 on: April 18, 2020, 11:18 AM »
Just some general information.

As a rule of thumb, every 90º elbow added to the system is the equivalent of adding 10' of straight duct work.
Using 2 each 45º elbows with some space in between is better than a single 90º elbow.

The use of long radius elbows is always preferred.
https://www.oneida-air.com/ductwork/standard-ducting/long-radius-adjustable-dust-collection-elbows

You're talking about duct work which is metal and also talking about pvc pipe which is plastic, is this system a hybrid and you're using both?

Increasing the diameter to 5" will decrease the velocity, I'd just stick with the 4".
« Last Edit: April 19, 2020, 09:26 AM by Cheese »

Offline jeffinsgf

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Re: Dust Collection System
« Reply #3 on: April 18, 2020, 12:55 PM »
I was in favor of running the duct at 5-inch, until I read that the inlet to the dust collector was 4-inch. I don't think you want to run duct any larger than the inlet size. That is a (very) non-professional opinion...it just seems counter-intuitive to me.

Offline Alanbach

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Re: Dust Collection System
« Reply #4 on: April 18, 2020, 01:26 PM »
Two things. First, I have 5” duct run to my Sawstop (4” outlet on the saw) with a 5” reducer at the saw per the works great with my 2hp cyclone system. Doing that at the tool end as opposed to what your doing (at the DC end) might make a difference, I don’t know.

Second, can you remove the splitter that creates two 4” openings on your DC and see what’s underneath. It might be a larger opening???

Offline rst

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Re: Dust Collection System
« Reply #5 on: April 18, 2020, 02:03 PM »
Duct reduction should always be at the tool end.

Offline ryanjg117

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Re: Dust Collection System
« Reply #6 on: April 19, 2020, 03:12 AM »
Can you tell us more about your dust collector (make, model, horsepower)?

I ran 6" PVC along the ceilings of my shop, but my DC was designed for it. Only stepping down diameter at the tool end, and only when absolutely required. You'll usually end up with some amount of flex-hose near the tool as well, just to keep some flexibility for moving the tool around. It's wise to keep that flex hose to a minimum since it has much more internal resistance than the smooth walls of PVC pipe.

Note, the price on PVC S&D pipe goes up exponentially once you pass 4" I think.

Offline Cheese

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Re: Dust Collection System
« Reply #7 on: April 19, 2020, 10:52 AM »
You'll usually end up with some amount of flex-hose near the tool as well, just to keep some flexibility for moving the tool around. It's wise to keep that flex hose to a minimum since it has much more internal resistance than the smooth walls of PVC pipe.

As Ryan noted, you'll probably have to install some flex hose somewhere in the system. Use as little as possible because of its reduced CFM capabilities. Properly support it to prevent kinking and if possible "stretch" it to maintain the smoothest interior surface.

Here's some interesting reading, some things I agree with while some others I don't...however, it's still information.  [smile]
https://billpentz.com/woodworking/cyclone/ducting.cfm

For an elegant method to attach the duct hose to the tools, I prefer to use these. They simply couple together with magnets.
https://magport.net/collections/all




Offline Climber39

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Re: Dust Collection System
« Reply #8 on: April 20, 2020, 10:06 AM »
Just some general information.

As a rule of thumb, every 90º elbow added to the system is the equivalent of adding 10' of straight duct work.
Using 2 each 45º elbows with some space in between is better than a single 90º elbow.

The use of long radius elbows is always preferred.
https://www.oneida-air.com/ductwork/standard-ducting/long-radius-adjustable-dust-collection-elbows

You're talking about duct work which is metal and also talking about pvc pipe which is plastic, is this system a hybrid and you're using both?

Increasing the diameter to 5" will decrease the velocity, I'd just stick with the 4".

My apologies, I should've been more clear about the materials I'm considering.  I was using "ductwork" as a generic term, not to describe the material. I'll probably end up using PVC, as it appears to be more cost effective.

Offline Climber39

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Re: Dust Collection System
« Reply #9 on: April 20, 2020, 10:08 AM »
I was in favor of running the duct at 5-inch, until I read that the inlet to the dust collector was 4-inch. I don't think you want to run duct any larger than the inlet size. That is a (very) non-professional opinion...it just seems counter-intuitive to me.

That was my general feeling as well.  But I kept hearing that I should keep the duct as large and straight as possible. Thank you for responding.  You guys are a tremendous resource.

Offline Climber39

  • Posts: 88
Re: Dust Collection System
« Reply #10 on: April 20, 2020, 10:10 AM »
Two things. First, I have 5” duct run to my Sawstop (4” outlet on the saw) with a 5” reducer at the saw per the works great with my 2hp cyclone system. Doing that at the tool end as opposed to what your doing (at the DC end) might make a difference, I don’t know.

Second, can you remove the splitter that creates two 4” openings on your DC and see what’s underneath. It might be a larger opening???

That's a great idea,  I didn't think about removing the splitter. Definitely going to check that out tonight.

Offline jeffinsgf

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Re: Dust Collection System
« Reply #11 on: April 20, 2020, 10:12 AM »
I know the OP is looking to put together a central system, but I want to hijack the thread long enough to second Cheese's comment about Magport. I just put them on all the equipment in our model shop, and they're brilliant. If you're rolling one dust collector around to different machines, or swapping one central branch between two machines, I would highly recommend Magport.

Offline CeeJay

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Re: Dust Collection System
« Reply #12 on: April 21, 2020, 07:41 AM »
This is my system which I installed over Christmas:


 
It’s a 4” pvc system running off a 2hp DC. It’s 4” all the way from DC to machine for each of the 4 machines and each machine has a 4” port. Blast-gate at each machine. Copper wire run through each length, bare metal grounded at the DC and each machine.

For the table saw it’s about 20’ of duct, 2 blast gates, 3 x 45 deg bend and 3 x 90 deg bend. The suction is OK but could be better. For the jointer, thicknesser and bandsaw it’s fine. So maybe in 10 years or so I might upgrade to 6” duct. The intake on the DC is 6”, currently with a 4” reducer.

I was going to run a floor sweep as well but I just use the CT Midi now so this system will stay dedicated to the large machines with the CT for power tools.


Sent from my iPhone using Tapatalk

Re: Dust Collection System
« Reply #13 on: November 07, 2022, 11:18 AM »
Hello, gents! I was searching for some help setting up my duct system, but I'm afraid the information is too hard to understand. If any of you know a decent air duct-related company to approach? I need to clear and fix my duct system in two houses, so that any advice would be greatly appreciated. I moved to a new place last year and didn't have any good contacts in the UK. At the old place, I approached the TopAir Systems company when I had any issues with my ducts, and I need to mention that they were working professionally and always providing great prices for their services.
« Last Edit: November 10, 2022, 02:16 PM by filadelfocustomized »

Offline Muttley000

  • Posts: 71
Re: Dust Collection System
« Reply #14 on: November 07, 2022, 08:34 PM »
Hello, gents! I was searching for some help setting up my duct system, but I'm afraid the information is too hard to understand.
I would suggest this book, it was greatly helpful to me
Woodshop Dust Control: A Complete Guide to Setting Up Your Own System by Sandor Nagyszalanczy
ETS EC 150
TS55 FEQ
CT 36

Offline DavidR8

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Re: Dust Collection System
« Reply #15 on: November 08, 2022, 12:59 AM »
This is my system which I installed over Christmas:


 
It’s a 4” pvc system running off a 2hp DC. It’s 4” all the way from DC to machine for each of the 4 machines and each machine has a 4” port. Blast-gate at each machine. Copper wire run through each length, bare metal grounded at the DC and each machine.

For the table saw it’s about 20’ of duct, 2 blast gates, 3 x 45 deg bend and 3 x 90 deg bend. The suction is OK but could be better. For the jointer, thicknesser and bandsaw it’s fine. So maybe in 10 years or so I might upgrade to 6” duct. The intake on the DC is 6”, currently with a 4” reducer.

I was going to run a floor sweep as well but I just use the CT Midi now so this system will stay dedicated to the large machines with the CT for power tools.


Sent from my iPhone using Tapatalk
If your collector has a six inch inlet I'm curious why you reduced down to four inch duct. That's really big reduction in area.

Offline Bob D.

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Re: Dust Collection System
« Reply #16 on: November 08, 2022, 06:40 AM »
I know the OP is looking to put together a central system, but I want to hijack the thread long enough to second Cheese's comment about Magport. I just put them on all the equipment in our model shop, and they're brilliant. If you're rolling one dust collector around to different machines, or swapping one central branch between two machines, I would highly recommend Magport.


I've been using MagPorts on most of my equipment for the past couple years. I bought a 4x2 MagPort Adapter and use it with some short runs of 2" flex to connect to my spindle sanders which are on wheels and stashed back in a corner of the shop until needed. Then I roll them out and connect the dust hose to a 4" MagPort connection I Tee'd off the run to my disc/belt sander and keep capped with a blind flange. When I need to use a spindle sander I can pop the blind off and connect the 2" hose with MagPort flanges on each end and another 2" MagPort on the tool. I know those connections can all be made with friction fit connections but they fall out some times and the MagPorts have never let go unless I physically disconnect them.
-----
It's a table saw, do you know where your fingers are?

Offline festal

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Re: Dust Collection System
« Reply #17 on: November 08, 2022, 07:18 AM »
wonder how magports compare to rockler ones?  I went with rockler collapsable hose and quick connect.  Seems to work ok but always looking for improvement

Offline Mini Me

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Re: Dust Collection System
« Reply #18 on: November 08, 2022, 08:20 AM »
Putting a central ducted system is not an inexpensive thing to do so getting it right and not wasting that money seems pretty sensible to me.

Forget quoted horsepower, it means very little

Use the extractor with the biggest impeller and when a salesman tries to tell you his 3hp DE will be better than a 2hp ask how big the impeller is in both and don't be surprised to find it is the same size.

NEVER NEVER use 4" ducting ALWAYS use 6" as it will flow about 1200CFM against about 650 CFM for 4"

Modify all machine ports to be 6" otherwise you may as well use 4" all the way and will do a very poor job due to low flow restrictions.

I would never install a single phase dust extractor when a three phase unit can be run from a single phase supply via a VFD

Using the biggest impeller (at least 15") and three phase/VFD means you can run it slower reducing the noise levels

My next DE will have a 17" impeller and I should be able to run it at about 40hz which will mean it will be very quite in operation.

Offline ChuckS

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Re: Dust Collection System
« Reply #19 on: November 08, 2022, 10:09 AM »
wonder how magports compare to rockler ones?  I went with rockler collapsable hose and quick connect.  Seems to work ok but always looking for improvement

In terms of effectiveness in connection, they're the same. You pay more for the magports because you can change the connection with one hand if that matters.

Offline jussi

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Re: Dust Collection System
« Reply #20 on: November 08, 2022, 11:51 AM »
It depends on how deep into the rabbit hole you want to dive. If you want a really accurate calculation you need to find the fan curve for your dust collector, calculate static pressure drops and figure out if the cfm and fpm are adequate for a given tool associated to the run for that tool.  I just went through the process because I’m doing the same as you.  The calculations themselves aren’t hard but in retrospect probably overkill.  In general I think dc with 1.5hp use 4” ducting and 3hp use 6”.  The idea of going as big as possible is also incorrect IMO.  Even if your dc has a larger inlet. For example I have a 3hp dc with an 8” inlet and initially my thought was to run 8” through out but when I did the math I found the cfm to be about the same with 6” but had a much lower fpm with the 8”. Not to mention the extra cost when going from 6” to 8”.  Thats another thing to consider fpm.  Most of the time people just talk about cfm but fpm is also just as important.   You need 3500 fpm to keep dust airborne so even though you have enough cfm you may lack fpm. In which case you may have to actually increase sp by tapering down the pipe or partially closing the blast gate.  As mentioned use as little elbows as possible and use elbows instead of hose when possible.  With 4” ducting a 45 degree elbow adds an effective  3’ to your run and 90 degree adds 6’.  Larger diameter ducting adds even more and hose add significantly more.   

If you want to do the actual math I can post a link when I get home to a wood mag article that explains it pretty well. 
« Last Edit: November 08, 2022, 04:39 PM by jussi »

Offline Mini Me

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Re: Dust Collection System
« Reply #21 on: November 08, 2022, 07:43 PM »
There is no need to calculate anything in a hobby workshop, if the impeller is around the 14/15" mark or bigger and 6" ducting used it simply works. Trust me, I have been doing this stuff for many years and have never calculated anything even in small commercial set ups. The whole idea of a bigger impeller in the Clearvue Max was to equal the airflow of the 1800 in markets that had a 50hz supply and it was never intended for the US market at all. I was the first to use a VFD on the Max to uprate it to 60hz and Bill Pentz always recommended a larger main duct to support the increased air flow. The whole idea of using a bigger impeller is to achieve the required air flow at a slower speed using 6" ducting (around 1200CFM) AT the MACHINE port and you can't do that unless the port is enlarged to 6". As I said, I have been doing this stuff commercially for over 10 years and people simply complicate it for no good reason and doing that discourages others from installing ducted systems. Read the stickies at the link below, the main contributor is a world expert on clean rooms so he knows a thing or two and certainly more than me.

For the best DE information for hobbyists on the planet go to here

https://www.woodworkforums.com/f200