Cyclone Ducting

[Joseph Fronio]

Have a 3hp laguna mobile cyclone and want to run permanant duct work in basement.
Was going to try Home Depot hvac duct. Any suggestions on sizing? The cyclone has an 8" iinlet and
15.8" impeller. Can I run an 8" main line across the basement ceiling and come off with 6" for tools?
tools being hooked up are 3hp pcs sawstop, powermatic 8" jointer, kapex miter saw, seperate router table,
And 5hp woodmaster 4in1 planer. Any suggestions would be greatly appreciated. I can't-stand connecting/disconnecting/connecting, tripping over the hoses, or smashing my head into the 3 way 4" inlet any longer.

[Jim German]

Don't use Home depot HVAC Ductwork, the dust collector will collapse them. If you find a good HVAC supply store, the heavier gauge ducting from them (at least 26 gauge) would work. Other folks have used PVC with good success. Running an 8" truck with 6" or 4" to individual machines works well.

[Joseph Fronio]

Thanks for the advice. I may do that. I saw a thread where people are using hd pipe with no problems.

[Joseph Fronio]

Any other suggestions?

[Jamie Buxton]

I have a 2 1/2 horse cyclone with ductwork from HD HVAC snaplock parts. Dunno the sheet metal gauge -- whatever the standard stuff is they sell. The ducts have been in place for seven years now, and they haven't collapsed. It is all 6" round.

[glenn bradley]

Thanks for the advice. I may do that. I saw a thread where people are using hd pipe with no problems.

I have also read threads where this is the case.


I have a 2 1/2 horse cyclone with ductwork from HD HVAC snaplock parts. Dunno the sheet metal gauge -- whatever the standard stuff is they sell. The ducts have been in place for seven years now, and they haven't collapsed. It is all 6" round.

There's one now ;-)

[Michael W. Clark]

I would prefer running 6" throughout, and increase the port size as much as possible at the tools.

The reasoning I say all 6" is because you need to pull about 1400 CFM in an 8" for the recommended duct velocity. In a 6", you only need 800 CFM. Granted, if you use 8" for the main, then neck down to 6", you are likely to pull more than 800 CFM in the 6", but I doubt you will have enough fan to pull 1400 CFM through the 6" branch. Remember, your cyclone pressure drop also increases with higher flow.

Additionally, 6" duct and fittings will be a lot less expensive. I checked prices at a local HVAC store, and their prices were comparable to HD (maybe a little higher), but had much better selection, and they delivered. I am going to use some register fittings for hoods, some horizontal take-off, some vertical take-off in 5" and 6". They also have 6x5x3 laterals (TS connection) and 5x4x3 laterals (Router Table and BS). You can also order from HD and Amazon on-line. Some fittings were cheaper there.

Mike

[Mark Engel]

Oneida Air (http://www.oneida-air.com/homepage.asp?) and Penn State Industires (http://www.pennstateind.com/) both have a good selection of duct and fittings. Oneida offers free shipping for orders over a certain dollar value.

[Ole Anderson]

Go with a 7" main and 6" main drops, you will hit the sweet spot for 800-1000 cfm. 6" is good unless you sometimes have more than one gate open. Home Depot snap lock is fine as long as you get the 26 gauge, yes, the cheap 30 gauge will collapse. Not all stores carry the 26 gauge stuff. And like Michael says, check with your local HVAC supplier and also look in the YP for a local specialized tin knocker shop.

[Brett Bobo]

Timely post as I'll be pulling the trigger on purchasing the "premium" ductwork today from Penn State. Being in the Houston area and having access to a number of spiral duct fabricators, I was certain that sourcing locally would be a cheaper option and avoid the shipping charges as well. I must have literally called about a dozen fabricators all over the Houston area and received estimates from about half of those. Given that spiral duct is commonly used for commercial or industrial applications, some of these fabricators wouldn't sell retail or to an individual and in turn, wouldn't provide me with an estimate. Also, my preference was to single source everything to avoid purchasing items from several different places and none of the fabricators could provide me with everything. As much as I wanted to purchase locally, all roads ended up leading back to Penn State for both a competitive price and the quality of the product/gauge of material for duct and fittings.

Just a note about estimates, it's imperative that you do an apples-to-apples comparison (or understand the differences and possible value added) as I found differences in the specs for the fittings between several fabricators. The 24 gauge spiral duct was straight forward/comparable; however, the gauge and fabrication process of the fittings varied considerably. I'm not well-versed with the SMACNA specification but regardless, the gauge of the fittings quoted ranged from 24 to 20 to accompany the 24 gauge spiral duct. Also, depending on the type of fitting, the fabrication varied from gore-locked, spot welded, fully welded, etc. and depending on the process, the gauge of the material to be used was effected as well.

All that to say just do your homework and understand exactly what you're purchasing so you don't have any surprises.

[Peter Kelly]

Grainger for snap-lock 26ga duct and hangers: http://www.grainger.com/product/DUCTMATE-6-In-Dia-6EKF0?s http://www.grainger.com/product/DUCTMATE-Strap-Hanger-6PFZ3
Kencraft for fittings: http://www.kencraftcompany.com/Dustindex.htm#pipe
Blastgate Co for gates, flex hose and spiral pipe should you go that route: http://blastgateco.com


All of the above retailers accept credit cards and ship nationally. I spent a long time researching steel duct and this seemed the best route. Blastgate Co has decent pricing on spiral pipe but the fittings and shipping get a bit costly.

Penn State's pricing is outrageous. Onieda is also pretty expensive but they do have metric to English adapters.

[Brett Bobo]

Penn State's pricing is outrageous

As a generalized statement, this is simply not true based on my experience. In fact, they were the second lowest quote I received for the entire ductwork package, even with shipping costs included. Sure, no one particular manufacturer will have the lowest pricing for every component for the ductwork system but even when doing an itemized comparison, they were competitive when you factor in everything, not just base cost.

[Michael W. Clark]

I'm not well-versed with the SMACNA specification but regardless, the gauge of the fittings quoted ranged from 24 to 20 to accompany the 24 gauge spiral duct.

Hi Brett,
I’m only familiar with SMACNA as it pertains to industrial dust collection ductwork. There are five SMACNA duct classes. The duct class is usually specified by the engineer, but SMACNA does offer some guidance. Spiral duct is only listed for classes 1 and 2 (fume and light dusts), and class 5 (corrosive fume). Most industrial wood dust applications are classes 2, 3, or 4. The higher the class, the heavier the construction requirements, (gauge, stiffeners, flanges, etc.). In industrial, the fittings are often made heavier gauge than the duct.

I would think that spiral would serve a home/hobby shop and some commercial shops very well. Be wary of the fittings, since alot of this is used in HVAC. Many of the HVAC fittings are not good for DC.

Mike

[Jim German]

Well if you're still skeptical here is the 30 gauge 8" duct I got from HD. That was on my Clearvue CV1800, and that was downstream of a 4" branch.

You might be able to get away with it for 6" ducts, but why risk it? The 26 gauge stuff that I got from a HVAC supply house was only like 5 bucks more for 10'.

277431

[Michael Mahan]

Well if you're still skeptical here is the 30 gauge 8" duct I got from HD. That was on my Clearvue CV1800, and that was downstream of a 4" branch.

You might be able to get away with it for 6" ducts, but why risk it? The 26 gauge stuff that I got from a HVAC supply house was only like 5 bucks more for 10'.

277431
did that happen as soon as you started up the ClearVue ??

[Jamie Buxton]

Well if you're still skeptical here is the 30 gauge 8" duct I got from HD. That was on my Clearvue CV1800, and that was downstream of a 4" branch.

You might be able to get away with it for 6" ducts, but why risk it? The 26 gauge stuff that I got from a HVAC supply house was only like 5 bucks more for 10'.



Did you have all the blast gates closed when the duct collapsed?

[Jim German]

did that happen as soon as you started up the ClearVue ??

Yep
I believe I had a 4" gate open at the end, they might have all been closed though.

[Alan Bienlein]

I get a kick out of reading about don't buy the snap loc from the home centers as it's to thin and will immediately collapse on you. I say hog wash as my whole system is done with the snap loc from Lowes and Home Depot. I can close all blast gates with out fear of collapse and I run the same 16" impeller and 5 hp motor as the Clear Vue on my cyclone.

The difference between me being able to use it and others having it collapse is all in how you hang your duct. If you want to be lazy and just use a strap or a tie wrap to hang it it will definitely collapse but if you take the time to make a ring out of some 1/2" ply to slide over the duct work then it WILL NOT collapse.

[Jim German]

I get a kick out of reading about don't buy the snap loc from the home centers as it's to thin and will immediately collapse on you. I say hog wash as my whole system is done with the snap loc from Lowes and Home Depot. I can close all blast gates with out fear of collapse and I run the same 16" impeller and 5 hp motor as the Clear Vue on my cyclone.

The difference between me being able to use it and others having it collapse is all in how you hang your duct. If you want to be lazy and just use a strap or a tie wrap to hang it it will definitely collapse but if you take the time to make a ring out of some 1/2" ply to slide over the duct work then it WILL NOT collapse.

Sure, sure you can reinforce your 30g ductwork (which is what you're doing with your ply). Or you could just spend a couple bucks more and get thicker stuff.

[Paul McGaha]

I've seen pictures of thin gauge duct collapse from being connected to a cyclone.

When I did my system I bought the spiral duct and fittings from Oneida. If I had to do it again I would buy the fittings from Oneida and try to buy the spiral duct local (It's expensive to ship).

Oneida has really high quality elbows. Long sweep, heavy duty, perfect for dust collection.

I'm not experienced with the duct and fittings from Penn State Industries.

Good luck with it.

PHM

Edit - I just looked at the Penn State Industries duct and fittings, It looked like quality material to me.

[Alan Bienlein]

Sure, sure you can reinforce your 30g ductwork (which is what you're doing with your ply). Or you could just spend a couple bucks more and get thicker stuff.
I would be spending more than a few dollars trying to locate "the thicker stuff". The home centers are a lot more convenient and making simple brackets like shown in this picture from scrap lying around the shop serves two purposes. It provides a convenient way to support the duct work and yes it reinforces the duct work in that it is forced to stay round with a negative pressure inside.
277465

[Michael W. Clark]

Alan,
I was thinking stiffeners too when thinner duct was first mentioned in this thread. How are you attaching the plywood rings to the duct and how often are you spacing them?

I can't find any pressure ratings or stiffening requirements in the industrial references I have. They only go down to 22 ga.

Mike

[Brett Bobo]

That's a clever idea and interestingly enough, ring stiffeners are commonly used to strengthen steel tubular members in the offshore industry.

[Michael Mahan]

I would be spending more than a few dollars trying to locate "the thicker stuff". The home centers are a lot more convenient and making simple brackets like shown in this picture from scrap lying around the shop serves two purposes. It provides a convenient way to support the duct work and yes it reinforces the duct work in that it is forced to stay round with a negative pressure inside.
277465

that's a GREAT Idea ! the more u use the better & doubles as hanger as well , best of all it looks to be clean install

[Joseph Fronio]

Thanks for all the great advice. Really helpful. I may stear clear of hd and go through a hvac dealer for the straight pipe.
Sounds like its a good idea to get the fittings through oneida or penn state. Why don't hvac fittings work for dust collection?

[David Kumm]

Also look at Kencraft for fittings. They are reasonable and work well with spiral too. Blastgate co fittings are undersized and don't maintain the inside to outside assembly that is preferred. HVAC fittings are used when you need adjustability but are short radius ells and you should stay with 2.5 x radius when you can and no less that 1.5x radius. No Tees. Wyes are usually backwards relative to DC fittings in the way they attach to the pipe because they are designed for blowing air rather than pulling it. Dave

[Michael W. Clark]

Joseph,
If you are referring to my comment abou the HVAC fittings, I was mainly referring to the spiral HVAC fittings for Brett at the spiral duct fabricators. A lot of them don't do tee-on taper fittings or laterals. In HVAC, you are running much lower velocity and very little (if any) appreciable dust load. They use tees, and reducers in-line when they branch. They also use elbows that are usually a 1D radius, sometimes 1.5D.

Contact a local residential HVAC company and price duct and fittings from them or find out where they get their duct. You often see it referred to as KD (knock-down) duct. I found a supplier close to here. I emailed them my list of fittings, then sent back an itemized price list and part numbers, said they could deliver it the next day for $10 extra when I'm ready.

[Alan Bienlein]

Alan,
I was thinking stiffeners too when thinner duct was first mentioned in this thread. How are you attaching the plywood rings to the duct and how often are you spacing them?

I can't find any pressure ratings or stiffening requirements in the industrial references I have. They only go down to 22 ga.

Mike

If it's a long run with multiple full length straight sections then I use one at each joint. They are easy to make as I used the same setup as I used to make my blast gates.

The rings are a snug slip fit. After I did mine I read about some one who made theirs either in two pieces or was it one piece that was cut on one side and when they put the pipe in they tightened the screw to clamp it in place.

The blast gates are held to the end of the duct work by 18 gauge brad nails I shot through a piece of thin wood so it wouldn't go thru the metal and lightly tapped them the rest of the way with a small hammer.

[Ole Anderson]

Stiffening rings aren't needed with 26 ga or heavier pipe. As stated multiple times don't use 30 ga pipe and you won't need rings. Use short 1/8" x 1/8" pop rivets at 12:00, 4:00 and 8:00 for connecting steel pipe and fittings. Best to rivet after you tape the joints with aluminum HVAC tape. http://www.sawmillcreek.org/showthread.php?158878-DC-Steel-Duct-Install&highlight=

[Michael W. Clark]

I agree, 26 ga. is preferred, but it is not as easily available to some. I had trouble finding it locally, took me awhile and I live near a major city. Most probably have access to the 30 ga stuff and the stiffening solution may be appealing.

In industrial systems (SMACNA), minimum gauge is spec'd by the class primarily for abrasion/errosion resistance. On a spec job, the SMACNA class is given, flows and SP, along with material bulk density. It is up to the duct supplier and installer to determine the most economical combination of gauge, stiffening, and support spacing.

[Todd Kinsfather]

If it helps anyone my local Lowes carries the 8" Diameter Snap Lock in 26GA @ $10.25 per 5ft length. The 7" and smaller are 30GA. Our HD's are all 30GA. In the past others had reported this as well. They also seem to have more fittings than HD but the selection varies by store. Mine have things like 8x8x6 Y's and 8x8x7 Y's, etc. Unfortunately the Lowes website is near useless for locating specialty HVAC fittings in each store in my area.

[Jim Andrew]

I picked up an 8" elbow and a short piece of 8" pipe at Menards on Saturday, as I am changing the discharge on my cyclone, and was surprised to find that the elbow was a heavier gauge than the pipe. Put it up today, and used one old 30 gauge, and the new one I bought at Menards, was heavier. So check out Menards for elbows before paying a big price. It was less than 5$.

[Joe Pack]

If you have a Menards in your area, check their web page. The web page has heavier gauge HVAC pipe/fittings than they carry in the store, but they will ship to store or your home for next to nothing.

[Dennis McDonaugh]

My Ace Hardware stocks 26 gauge metal duct and its about twice expensive as the Home Depot version.