Installing ductwork for dust collector? Pics

[Steve Mathews]

I just ordered most of the ducts and fittings for my dust collection system. A few questions remain for the install that I'm hoping to resolve here. Photos are included below to give some sense of what I'm trying to accomplish. The first photo below shows a rough sketch of the layout. Along the wall where most of the drops will take place I was thinking of rolling the wye outlet about 45 deg. downward and connect the drop with an adjustable 90 deg. ell, essentially making it a rolling 45 deg. transition. I thought of doing this instead of having the wye outlet horizontal and dropping down with a straight 90 deg. ell. First of all, does anyone see any problems with this approach.
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Here's a photo of the wall where most of the outlets take place. I plan to run the duct above the wall ties as close to the wall as possible.
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Here's a photo of the dust collector. I have to rise up from the outlet to before getting to the wall. Would a couple of 45 deg. ells be better than using flexible hose. The size of duct at this point is 8"
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And lastly here is a photo of the dust collector installed in it's temporary location before I get a chance to add on a mechanical room. I may also hook up the compressor shown for my next project, installing shop air.
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[Malcolm McLeod]

After an epoch of research, I just put in an EF-5, and phase 1 of my ducting. Biggest thing I came away with after all the angst and engineering was the inlet duct run to the cyclone. People drop in 3-5 Hp of fan and then kill their air flow by installing 2 90*Elbows on the inlet to get to their horizontal run. This induces turbulence right at the inlet with no chance for the air to return to laminar flow.

Turbulent flow means the dust is moving in random directions - - but still forward with some average velocity.

Laminar flow means you have a fairly consistent velocity over the majority of the duct's cross section. This means the dust has the most possible kinetic energy as it hits the cyclone = hugs the wall = separates from the air. My advice is find a way - even if a bit inconvenient - to get a straight run ~10x the duct diameter into the cyclone. So, if you have 6" duct = 60" of straight duct.

- - not sure of my audience, so pardon the mini-fluid-dynamics course.:o

[Ken Fitzgerald]

Steve,

Here's a thread showing how I installed mine. https://sawmillcreek.org/showthread.php?77637-Finally-some-DC-progress

[David L Morse]

After an epoch of research, I just put in an EF-5, and phase 1 of my ducting. Biggest thing I came away with after all the angst and engineering was the inlet duct run to the cyclone. People drop in 3-5 Hp of fan and then kill their air flow by installing 2 90*Elbows on the inlet to get to their horizontal run. This induces turbulence right at the inlet with no chance for the air to return to laminar flow.

Turbulent flow means the dust is moving in random directions - - but still forward with some average velocity.

Laminar flow means you have a fairly consistent velocity over the majority of the duct's cross section. This means the dust has the most possible kinetic energy as it hits the cyclone = hugs the wall = separates from the air. My advice is find a way - even if a bit inconvenient - to get a straight run ~10x the duct diameter into the cyclone. So, if you have 6" duct = 60" of straight duct.

- - not sure of my audience, so pardon the mini-fluid-dynamics course.:o

Malcolm, I don't know if you really meant laminar flow in the technical sense, but if you check the Reynolds number for typical dust collection velocities and duct sizes you'll see that it's all turbulent flow, not even close to laminar.

[Steve Mathews]

Ken - Thanks for the link to the thread about your duct install. That was very helpful.

Here's a not much better sketch showing my intended layout. I'm trying to stay close to the one wall with the main run because 1) that's where most of the equipment is located and 2) the height for attaching hangers is much lower. I'm still a little concerned about rolling the laterals to the drops and making an elevation change at the DC. My plan for the latter at the moment is to use a couple of 45s along with a short section of hose to compensate for vibration at the DC. Again, any suggestions are most appreciated.432938

[Ryan Yeaglin]

Steve, as someone who works in the trades I can appreciate your drafting skills!

[Steve Mathews]

Forgot to mention that I'll probably exhaust the DC outside without filtering for now. That's the direction shown in one of the photos. My closest neighbor is at least a couple hundred yards away. It may be a good idea to install some type of louver or flexible gate to keep bugs and critters out.

[Malcolm McLeod]

True dat. But audience :: I needed to use some term to delineate difference in flow. (Not sure how many here speak Reynolds:D).

[Steve Mathews]

After an epoch of research, I just put in an EF-5, and phase 1 of my ducting. Biggest thing I came away with after all the angst and engineering was the inlet duct run to the cyclone. People drop in 3-5 Hp of fan and then kill their air flow by installing 2 90*Elbows on the inlet to get to their horizontal run. This induces turbulence right at the inlet with no chance for the air to return to laminar flow.

Turbulent flow means the dust is moving in random directions - - but still forward with some average velocity.

Laminar flow means you have a fairly consistent velocity over the majority of the duct's cross section. This means the dust has the most possible kinetic energy as it hits the cyclone = hugs the wall = separates from the air. My advice is find a way - even if a bit inconvenient - to get a straight run ~10x the duct diameter into the cyclone. So, if you have 6" duct = 60" of straight duct.

- - not sure of my audience, so pardon the mini-fluid-dynamics course.:o

Actually, I may be able to run straight into the DC inlet by lowering the 8" duct along the back wall to 7'. Supporting wouldn't be a problem because it would be bracketed to the wall. Two 45 deg. ells would also be eliminated in the process. The more I think about it the better I like it. Thanks Malcolm!

PS I don't know if this is relevant to air flow but straightening vanes are frequently used in hydraulics, especially at inlets to pumps to reduce turbulence. Maybe it can also be applied to air flow.

[Thomas Wilson]

True dat. But audience :: I needed to use some term to delineate difference in flow. (Not sure how many here speak Reynolds:D).
The term you are looking for is “fully developed” meaning that the effects of elbows on the velocity profile have decayed away. Typical straight pipe distances of 5 to 10 pipe diameters are needed for fully developed turbulent flow.

[Jim Becker]

You can use adjustable elbows to do the slight bends that get "down" to your inlet from your intended duct height. Ideally, you want a few feet of straight run into the cyclone inlet before any direction changes, but sometimes you have to do what you have to do and if the bend is very gentle, you'll be fine. NEVER use flex hose for this kind of thing, however. If you do use this technique once you have everything set with the angles and you confirm it's how you want it, be sure to fully seal up the ten billion joints in the adjustable elbows with mastic and/or foil tape.

[michael dilday]

I don't really understand what you mean by "rolling the wye outlet about 45 deg. downward and connect the drop with an adjustable 90 deg. ell, essentially making it a rolling 45 deg. transition". My system has a 3 hp Jet Cyclone and I drop from a 9' ceiling with a 90 directly into the cyclone using spiral steel pipe. My cyclone separates nearly 100%. Filling a 55 gallon drum and I may get a few tablespoons past the cyclone into the canister bag. I do understand about the straight pipe into the cyclone but in my shop it just didn't work out. One thing I might be able to add is the 45's out of the main should be horizontal there 90 for each drop. This will keep debris from dropping into the drops and clogging.

[Matt Day]

So it looks like you have a change in ceiling height, just north of your DC, right? If you keep your layout, I’d run 5-6’ of straight pipe before any 45’s.

Have you considered a straight run diagonally from your DC and branching off from there? So from the DC toward the bandsaw? At some point, maybe after 8’ you could roll the main above the ceiling joists if you wanted.

[Steve Mathews]

Clarifying what I'm planning to do now ... The 8" duct coming straight out of the DC will be about 7' high until just past the lathe. That should provide over 20' of straight duct to the DC. The 6" branch at the 8"x4"x6" wye will be pointed up at some angle to receive a short section of 6" duct and an adjustable 6" ell at about 10' high. This will be height of the remaining 6" run, which will be just above the wall ties. Delete Section A-A in the last sketch. There are no fittings immediately after the DC.

[Tom Dixon]

Why not raise the cyclone up on a platform and just run a longer flexible hose down to the collection bin on the floor so you can get a straight run out of the cyclone at the height you want to run your pipe?

For my DC I built an external shed on a platform so that the Height of the DC inlet was exactly the height of the 8" main running down the center of the shop.

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[David L Morse]

True dat. But audience :: I needed to use some term to delineate difference in flow. (Not sure how many here speak Reynolds:D).

You're right, context is important. I didn't mean to sound like a 240 vs 220 pedant.:eek:

I sometimes call it "undisturbed" or "reasonably uniform".


The term you are looking for is “fully developed” meaning that the effects of elbows on the velocity profile have decayed away. Typical straight pipe distances of 5 to 10 pipe diameters are needed for fully developed turbulent flow.

Well, at dust collection velocities you need more than 10D to get fully developed flow. But 5D to 10D from a disturbance is usually good enough for both testing and not too much system effect (interaction between closely spaced components).

There's a difference between what's agreed upon for reproducible testing and what's required for actual operation. Per AMCA a 10D test pipe is used for testing DC type fans. That convention has been extended to the testing of cyclone-fronted hobbyist dust collector systems. That means you should be able to reproduce a manufacturer's test data if you're careful. It doesn't mean the system quits working if you only have 1D, just that you get different (usually not as good) results.

So, a 90 close to the input of a cyclone will almost certainly increase the loss coefficients of both the 90 and the cyclone (system effect). It will also change the collection efficiency vs particle size curve, probably spreading the transition region somewhat. I think the overall impact of that will be a lot less than a reduction in airflow or a collection bin leak. That's an opinion, I've not seen any actual data on what inlet disturbances do to collection efficiency.

[Steve Mathews]

Tom - In answer to your question, my longer range plans are to build a separate mechanical room or shed as you put it for the DC and air compressor. But for now, to get the system up and running, I decided to install the DC where it is shown. It is elevated as high as it will go without hitting the mezzanine floor joists. BTW, your DC installation and shop for that matter look great! I can only hope that mine looks half as good as yours and Ken's when done. After looking closely at your setup I decided to make another change of plans and give up on the idea of angling the wye branches downward. The way you and Ken installed yours looks like it should. Is it possible to post some additional pics of your setup showing duct hangers, vertical supports, various machine connections, etc?

[Jim Becker]

Yea, a pesky ceiling can get in the way sometimes. LOL I did stick the motor of my Oneida system up between the joists which gave me the headroom I needed to easily fit a 55 gallon bin under it with an 8' ceiling level. (bottom of joists)

[Dave Mills]

You're probably way ahead of me, but a pic just for interest. I waited for the final vertical positioning of my dust collector until I had the ducting and angles set so that I could run a 45 up toward the ceiling, and a single 90 to make the turn at the ceiling. It saved a couple of turns over the version designed by Oneida. My overall system is much smaller than yours, but the 7" main duct is the full length along the ceiling, I notice yours drops to 6" (not saying that's an issue, I don't know enough to suggest that). My drops from the ceiling are 45 wyes followed by a 45 turn to go vertical, except the very last one which is a 90 straight down.

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[Steve Mathews]

Nice work Dave! I really wanted the clamp together duct and fittings in your install but couldn't justify the shipping expense. I do have one drop off a wye the same as yours that will be for the lathe. I was originally planning to run all of the mains 6" but the purchase of the used Oneida DC with an 8" inlet prompted me to increase the run along one wall to 8". It seems logical to make the transition to 6" at a wye.

[Dave Mills]

Thanks Steve! Yes, the words "nordfab" and "justify" have never been in the same sentence together :)

[Steve Mathews]

Thanks Steve! Yes, the words "nordfab" and "justify" have never been in the same sentence together :)
Actually, the price for the ducts and fittings seemed reasonable. What killed it for me was the shipping which was more than what I'm paying for the current selection of materials alone.

[Jim Becker]

I was originally planning to run all of the mains 6" but the purchase of the used Oneida DC with an 8" inlet prompted me to increase the run along one wall to 8". It seems logical to make the transition to 6" at a wye.
Similar here. My 2hp Oneida system has a 7" inlet, so I run 7" to the first major wye and transition to 6" there to match the original duct work I installed for an even earlier version of the Oneida cyclone back in 2000. That was the logical transition point and it's worked out well. Single worker/single machine systems don't need to step down, but back when I was designing my collection network, it was still the way things were being recommended by the vendor. Should I ever relocate the shop due to downsizing, etc., I'll probably simplify things and stick with a 6" main past that first wye with all my drops at 5" which accommodates any tool I have in any location...my slider and J/P have 120mm ports (~5"). I like my 5" floor sweeps the best...they are more efficient than the 4" floor sweep for sure. Other tools, I'd reduce at the specific tool.

[Steve Mathews]

Most of the materials won't be delivered until next week at the earliest but I'm already looking at making changes. Instead of installing the 6" line above the wall ties I may move it below. I thought not to do that earlier because of conflicts with light fixtures and at least one air cleaner. But after looking at it again I may have enough clearance with the light fixtures and the air cleaner(s) can easily be moved. By lowering the duct I may be able to eliminate one fitting. It may also work out better with a mezzanine extension planned. It's been great receiving all of the suggestions and ideas here. I hate to think how many other changes would have to be made without the help.

[Ryan Yeaglin]

I feel the Norfab stuff isn't reasonable compared to spiral fittings. Norfab is great for someone that wants to install duct fast or change it a round (it's like legos). I'm a journeyman sheet metal mechanic, but my current job doesn't allow me to do home projects there so I more than likely I'll run PCV. I also don't like that all the common available 90s are 1.5 x center-line, I would make them 2x for a more gradual bend. Some systems I've installed have been as much as 4x center-line for foundries.

[Pete Costa]

What are some good options for cutting spiral pipe?

[Jim Becker]

What are some good options for cutting spiral pipe?

Drill a hole at the cut line and use a jigsaw with a metal cutting blade to run around the line. Putting blue tape on the "keep side" of the line will help guide you. A quick pass with a file will clean up any sharpness.

[Ole Anderson]

433061"Never use flex hose". My setup was so oddball, I had no choice. I used the aluminum flexible duct off the shelf in 7" size from HD. Smooth bends unlike a series of cobbled up twisted bends using standard multi part twist-to-fit 90 or 45 degree bends. Even then I had to use a 45 right at the inlet. Works fine for me. I don't get unusual amounts of dust in my filter. I tap it out every 35 gallons of sawdust and blow it out with a power blower every 3 barrels of chips. As good as 6 feet of straight pipe into the inlet? Of course not.

[Jim Becker]

Ole, the aluminum stuff you used is a little smoother inside than the typical flex hose used for connection to machines. That said, I'm surprised it's not getting crushed by your system unless you found a much heavier product than I've seen in the store!

[Tom Dixon]

Tom - In answer to your question, my longer range plans are to build a separate mechanical room or shed as you put it for the DC and air compressor. But for now, to get the system up and running, I decided to install the DC where it is shown. It is elevated as high as it will go without hitting the mezzanine floor joists. BTW, your DC installation and shop for that matter look great! I can only hope that mine looks half as good as yours and Ken's when done. After looking closely at your setup I decided to make another change of plans and give up on the idea of angling the wye branches downward. The way you and Ken installed yours looks like it should. Is it possible to post some additional pics of your setup showing duct hangers, vertical supports, various machine connections, etc?

Steve I'll post what I think you are asking for. If you want me to zoom in on a machine connection or some other detail let me know and I'll gab another photo. As for hangers I used two types. For the main 8" trunk I went with a more rigid two piece clamping hanger (https://www.blastgateco.com/Pipe-Hangers.php) with 2 lengths of all thread which I connected to Sammys 3/8-16 x 2 Threaded Rod Hanger for Wood (https://smile.amazon.com/gp/product/B012HPTMTA) that I screwed into the ceiling joists through a washer. For all my 6" pipe I used a Tear Drop Pipe Hanger. one at least every 10 feet. for vertical drops I made clamping wall mounts using one of part of a 6" two piece clamping hanger and made a BB piece to mount to the wall.

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Here are various views of the full installation inside the shop.

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Well I reached the 8 picture limit. Let me know if there is some detail I missed that you are interested in.

[Tom Dixon]

What are some good options for cutting spiral pipe?

This was my solution. Cheap 2" castors and some scrap lumber. I bought the Eastwood metal cutting saw (https://www.eastwood.com/eastwood-mini-metal-saw.html) specifically to cut spiral pipe but is coming in handy for other projects now. I cut 8" and 6" pipe with what is shown and made another piece to screw on for 4" pipe. After a few tries I got really good with making virtually perfect cuts.


https://youtu.be/nvOXFkhoF2M

[Steve Mathews]

Steve I'll post what I think you are asking for. If you want me to zoom in on a machine connection or some other detail let me know and I'll gab another photo. As for hangers I used two types. For the main 8" trunk I went with a more rigid two piece clamping hanger (https://www.blastgateco.com/Pipe-Hangers.php) with 2 lengths of all thread which I connected to Sammys 3/8-16 x 2 Threaded Rod Hanger for Wood (https://smile.amazon.com/gp/product/B012HPTMTA) that I screwed into the ceiling joists through a washer. For all my 6" pipe I used a Tear Drop Pipe Hanger. one at least every 10 feet. for vertical drops I made clamping wall mounts using one of part of a 6" two piece clamping hanger and made a BB piece to mount to the wall.

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Here are various views of the full installation inside the shop.

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Well I reached the 8 picture limit. Let me know if there is some detail I missed that you are interested in.


Tom - Thanks for getting back to me with the additional pics, etc. Your installation along with an earlier comment by Jim Becker has motivated me to make yet another change. I really like the fittings you used that seem far superior to the adjustable type I ordered. Besides looking ugly the adjustable type may be a source for unnecessary leaks. It looks like the ones you used (?) are the same as offered by The Blastgate Co. If so the installation would also be easier in that crimping the fitting or pipe isn't necessary. At least that's what I understand from the description of them. I will be taking a bit of a lose in what was already purchased but I think it will for the better. I also like what you've done with all of your supports.

[Jim Becker]

Steve, you don't want to use crimps with spiral pipe...the smooth sleeves are the way to go!

[Tom Dixon]

+1 for smooth sleeves only As Jim said, They are the way to go!

All my pipe, fittings and hangers came from The Blastgate Co. I made my plan, from that made my list and then contacted them via email and asked for their best price including shipping. Their sales guy Dan gave me a discount of around 10% on the entire order which more than covered the freight cost. I ordered 4 8" pipe, 26 6" pipe, 1 4" pipe, 55 fittings, 20 pipe connectors, 16 hangers, 12 bast gates and some 4",5" and 6" flexible hose. I ended up not using the 6" hose and ordered a few other fittings later after making a minor change to my plan and Dan gave me the same discounted pricing for those odds and ends.

I also had The Blastgate Co. custom build me a 90 degree 6" connector for my Unisaw for around $90.

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[Steve Mathews]

Steve, you don't want to use crimps with spiral pipe...the smooth sleeves are the way to go!

Smooth sleeves? According to the The Blastgate Co. their fittings slip inside the spiral pipe. Hopefully the spiral pipe I'm getting locally has the same inside diameter.

Edit - Smooth sleeves = male pipe connectors by The Blastgate Co.?

[Ole Anderson]

Jim, the aluminum flex actually had a rated vacuum which was close to what I would be running, so I had my fingers crossed when I first tested it with all gates shut.

[Jim Becker]

Smooth sleeves? According to the The Blastgate Co. their fittings slip inside the spiral pipe. Hopefully the spiral pipe I'm getting locally has the same inside diameter.

Edit - Smooth sleeves = male pipe connectors by The Blastgate Co.?
We are talking about the same thing....

[Pete Costa]

Thanks gents!

[Dave Mills]

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Question for you Tom, if you don't mind. Did you make these plywood brackets - make them with a large hole saw? And then do you use HVAC strapping to hold the pipe to them? How wide is that strapping?

Thanks

[Tom Dixon]

Question for you Tom, if you don't mind. Did you make these plywood brackets - make them with a large hole saw? And then do you use HVAC strapping to hold the pipe to them? How wide is that strapping?

Thanks

Dave They are made by laminating two sheets of 3/4 baltic birch plywood together. Then I cut out 9" squares and used a 6" hole saw to cut out the middle. I set the lowest speed possible on my drill press. Then I used an oscillating spindle sander to clean up and enlarge the holes to around 6 1/8 ", cut them in half on a band saw and attached a 3"x13" piece of 1/2 baltic birch plywood for the base. I relieved any edges that weren't connected with a trim router and a 1/8" round over bit, sanded and put on a single coat of poly.

I did not use HVAC strapping. I used 1 side of a 1 1/2" wide two piece clamp hanger from The Blastgate Co (https://www.blastgateco.com/Pipe-Hangers.php). I drilled holes to use 5/16 lag screws to attach the strap clamp. They aren't fastened all the way to the wood. There is about a 1/2" to 3/4" gap but the pipe is held really snugly. I would mark my sheetrock walls through the attachment holes in the base and put screw in anchors in the wall before fastening them down if the hole location missed a stud.

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[Dave Mills]

Fantastic, Tom, thanks for the details!

[Bill Dufour]

I bought a flycutter for use in the drill press to make exact size holes. You have to turn the cutter depending on if you want a clean hole or a clean plug. Once you have it dialed in make a shallow cut in scrap and save the scrap as a guage. If you mess up you can screw a piece of scrap across the hole to allow a center hole. I had to do this to move a hole over 1/2 inch with a hole saw.
For deep cuts you have to grind some side relief on the cutter bit. It is just a standard 1/4 HSS lathe cutter. You could even get a carbide tipped one and cut marble.
Bill D.

https://www.generaltools.com/heavy-duty-circle-cutter

[Ole Anderson]

Flycutter for my 4" blast gates: https://www.youtube.com/watch?v=q5ORwZJ3ErE&feature=youtu.be I had scrap 1-1/8" particle board which was perfect. Using my mini-mill was a cut above using my drill press.

[Thomas Crawford]

Might be late but here's mine:
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Full 7" to the second split, about 36" straight. All 6" spiral after that. I've got no complaints.

I bought a ton of stuff from theblastgate co including some custom 22.5 connectors for my vaulted ceiling. Then I bought more from a local place. Not all sleeves and connectors are created equal. I had to use the crimpers in a couple spots which is not easy to do on spiral.

[Steve Mathews]

I'm getting close to finishing my dust collection system install and have a few questions. On interior drops is it necessary to brace the vertical ducts? Also, is it necessary to brace the horizontal runs? It seems to me that when the dust collector is turned on the ducts will move. All of my horizontal runs are supported with standard teardrop shaped pipe hangers and 3/8" rod.

[Jim Becker]

I have my drops secured to the wall for sure...

[Steve Mathews]

I have my drops secured to the wall for sure...

Same here for those that are along the wall but I have 2 drops more inside similar to what Tom Dixon shows in his pics. It looks like his are not braced, which is probably going to be OK.

BTW Jim, you were spot on about the Blastgate fittings being an improvement over the standard HVAC types. Glad I made the change.

[Ole Anderson]

Here are a few pics of my duct mounts:

[Tom Dixon]

Same here for those that are along the wall but I have 2 drops more inside similar to what Tom Dixon shows in his pics. It looks like his are not braced, which is probably going to be OK.

BTW Jim, you were spot on about the Blastgate fittings being an improvement over the standard HVAC types. Glad I made the change.

All my vertical drops along a wall have one brace. Ones away from the wall don't. Horizontal ones have one too. the photo below shows 3 wall braces. 2 vertical and one horizontal.
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[Jim Becker]

This drop for my router table (poor man's shaper attached to my slider) has a wood support that extends down from the ceiling rafters...you can just barely see it in the photo because of the angle.

https://megezw.bn.files.1drv.com/y4mzV9hh7LDjwKxCfIF1xdNZEM56UbUeebLMD8Nq-bF0E0C0vsn61v2HviZ0Kf6d3kKrc0Njcr0hV3C31DB-7rUIb7hV_7sZRbN0z8QD51fpXm6L0YQ3EFFnblnHfaYfHZBpFw WqxSYpHas6mFObltAIH6zBtZwRlaIxE9BtGw3lclIkDMCJ1acf 4uQNgktSoRUxsoMfpXijjoA5-NyjPky4A?width=660&height=660&cropmode=none