Adding a Long Duct Run to a Dust Collection System

A woodshop owner tries to figure out how to tie a distant machine into his dust collector, and decides to buy a dedicated vac instead.June 15, 2014

Question (WOODWEB Member) :
I have a 1200 cfm portable Delta collector that is dedicated to our wide belt sander. It is technically undersized for the machine but has always done the job quite well. Now I want to get our edge sander out of the main shop shavings collection system and I can either try to connect to the existing collector on the wide belt sander or get another dedicated collector, probably around 600 cfm for the edge sander.

The issue with tying into the existing 1200 cfm unit is that it is 60 feet of pipe away from the edge sander. It would be about 7' straight up to the ceiling and then around 53' along the ceiling over to the collector. Since that 1200 cfm collector and the edge sander both have 4" outlets it seems I would need to do a 4" pipe run. I fear stepping it down to 3" over by the sander end would not work very well. Does anyone have any thoughts on this?

Forum Responses
(Dust Collection and Safety Equipment Forum)
From contributor J:
600 CFM is a lot to get through any 4" pipe, let alone sixty feet of it. I think I'd use 5" pipe for as much of the run as possible. Particles from a sander will be small and light, so volume is more important than velocity. I would bet that the 1200 CFM rating on your collector (this is the 1.5 HP model I assume) is kind of a fantasy number, akin to peak horsepower ratings on vacuums and air compressors. It'll probably move 1200 CFM with perfectly clean filters and no ductwork attached, but not in practice. So I doubt it will be able to handle both the widebelt and the edge sander simultaneously.

From contributor F:
At 50' plus distance your 4" duct is going to create some serious resistance. I'm not sure how effective it will still be at that range? I don't remember the max cfm for a 4" duct but I think it's less than 600? You can find that info pretty easily on google I'm sure. Also, 3" is not an option, you won't have any performance with that small an opening. You could run a 5 or 6" duct and either drop down at the end, or increase the size of your dust hood, but I think it still will lose a lot of airflow at that distance.

Also, if you have someone edge sanding at the same time the wide belt is going, you may see a noticeable drop in performance for the widebelt.

A couple options off the top of my head:
1. Just buy a new portable for the edge sander - quick and easy.

2. Replace the dust collector that handles the widebelt with a larger capacity unit and use the smaller one for the edge sander.
3. Move the edge sander closer to the widebelt to decrease the amount of resistance the ducting will create.
4. Replace your main collector with a larger one that can handle all of your shop at the same time.

From the original questioner:
To contributor F: Starting with your last suggestion first, going to a larger system would not solve this issue. The existing Oneida system is plenty large to do everything. I just want to get the fine powder sanding dust out of it. It's not good for the filter or the collected shavings that horse people take.

Now on the other suggestions I'm sort of settling on the #1 - just buy another collector for dedicated use on the edge sander. I was leaning that way before posting here but thought I'd get some other opinions as well. Thanks for the input on the max cfm of 4" pipe. That is exactly where my understanding of the situation need some help.

From contributor S:
Factoring in the cost of 60' of pipe, and labor for installation you might as well buy a 1-2 hp collector to dedicate to the edge sander.

From contributor E:
You have to calculate the static pressure based on duct sizing and length of the duct run. Imagine sticking multiple straws together and trying to suck your drink from it. The more straws the harder you have to suck. Same goes with diameter. You can get more volume through a regular straw than you can through a coffee stir straw. The Oneida dust collectors are not designed for much static pressure, so I don't believe any additional ducting would just hinder your system. Also, 600 CFM through a 4" line equates to 7,000 FPM duct velocity which is unattainable with one of those Oneida collectors.

From Contributor K:
I too would like to keep the fine powder out of my main collection system. I'm thinking of connecting a Super Dust Deputy by Oneida between my widebelt sander and my Oneida cyclone collector. What do you think of this approach? I do know that when I connect the smaller version dust deputy between my shop vac and drywall sander itís amazing how much the deputy collects and how much longer the filter last.

From the original questioner:
To the original questioner: That's not a bad idea. I called Oneida tech support to discuss it because it could help with my table saw and resaw dust that is still getting to the filter on our 5hp cyclone system. With reference to the original question I posted I did end up putting a separate 2 hp bag collector on the edge sander. With the wide belt and edge sander off the 5hp cyclone system our filter goes a lot longer without needing to be cleaned. However as explained to me by the Oneida tech support people the cyclone is designed to draw out dust down to around 30 microns. A significant portion of the dust that is smaller than that will get to the filter regardless of how well your system is designed. She said the sanding powder we used to see in the filter was on the 5 micron level.

They could not tell if how much it would help to put their Super Dust Deputy into our 6" line that goes to the resaw and table saw. They did say it should help and would not be a problem for the system overall. So it's a matter of deciding if it's enough of a problem with the remaining dust I'm getting to the filter to invest in the effort of installing this small mid-system cyclone. As it is we are spending about 30 minutes once a month cleaning the finer dust out of the filter.

From Contributor K:
Which brings up the question - what's the best way to clean the power from the pleated filter on my 2 hp Oneida collector? I know using an air nozzle is the norm, but is there a better way?

From the original questioner:
We use a 6" wide soft brush on the end of a broom handle. It's the type of setup used to spread tar on a roof.

From Contributor K:
I am glad I don't have to brush-on tar anymore! Good tip for cleaning the filter though.

From Contributor Y:
After retirement my Oneida cyclone was more machine than I needed. I sold it and bought a Jet with a canister filter to run on one machine at a time. Without a separator the collector works well, but bags fill quickly. I put an old trashcan unit on and it kept impellers safe and removed a lot of debris, but it also knocked down performance significantly.

A couple days ago my Super Dust Deputy arrived. I used a 30 gal plastic drum for the base. After cutting the top out I had some old counter top I used for the lid. To seal it I just used self-adhesive foam weatherization strips. To hold it down I stopped at my favorite auto parts store and bought four of the rubber hold hold-downs like you see on big. I also cut a view port in the side and sealed a piece of clear plastic over it. I fired my collector up and it was far an apart an improvement on the trash can system. I can, again, clean the floor with it, but don't have to worry about nails and things working their way past the impeller blades. In short, a big thumbs up for the combo. One on each side of the shop and life is good, again.