silver duct

[Joe Shinall]

I see dust collection pictures on here all the time and I'm finally about to do my DC in my shop. What is the silver ducting that I see used alot and how good is it? Is it HVAC and if so, is there a certain name for it? I know PVC has different thicknesses and all, is there a certain thickness of this pipe and is it more cost effective than PVC?

[Doug Colombo]

Joe - Here is a link to a site that sells metal dust collection ductwork: http://www.blastgateco.com/Spiral-Pipe-and-Fittings.htm (I have not used this site or company or have any connection with them. I know someone that bought from them locally and was very pleased. Just sending the link to show you examples of the pipe). The metal pipe that most use seems to be the spiral pipe. From what I hear, HVAC pipe is too thin and will collapse. I used thin wall PVC when installing my system. In my old shop I ran 4" that I bought at the Borg - worked well the small shop that I had. I ran the same in my new shop and it works good, although after reading comments here on the creek, am looking at increaseing the size to 6" on the main runs, as this shop has longer runs that the old shop. One advantage to metal is you don't have to run the grounding wire in the pipe like you have to with PVC, you just connect the ground to the metal pipe and you are good to go.

[Lee Schierer]

Joe - One advantage to metal is you don't have to run the grounding wire in the pipe like you have to with PVC, you just connect the ground to the metal pipe and you are good to go.

You don't need a grounding wire on PVC either. It doesn't do anything inside the pipe but cause jams. Just use it for a while and the static problem will fade away. If your metal tools are grounded, you shouldn't have any static shock problems.

[Jim Becker]

Metal duct for dust collection systems should be a minimum of 26 gage or thicker to avoid issues with collapse. Regular HVAC duct is typically lighter 30 gage material. 26 gage is often sold as "stove pipe".

[james glenn]

I have the 26ga ducting and it works great so far.

It was much cheaper for me to use this than the PVC (even the 2729 was more expensive).
They only issue I had was that the wye's are design backwards for DC use. I just used my crimpers
and reversed the 'male & female' ends of the pipe and worked fine.

[Aaron Rowland]

You are on a long an twisted journey. LOL. I'm still confused after many years and three different duct systems. The opinons have changed radically in the past 5 years or so so keep up to date. At one time stepped or different diameter ducts were the rage. Tha'st out and 6" diameter ducts from the Cyclone or DC direct to the machine is in. PVC vs metal is still controversial but shifting I believe to PVC for the hobby /home shop. I've used both and PVC is so much easier to install, no leaking joints and super easy to add or remove a machine with a SawsAll.

6" PVC S/D (sewer and drain) or ATSM 2729 sells for about $1.26 a foot were I live. Walls = .115" (9 Ga.) and is super strong and crush proof. It may require a loop of grounded doorbell wire on the outside to drain off static in dry climates. Not a big deal.

Metal comes in various configurations. HD and Lowes sells 30 ga( .015 snap lock for HVAC systems for about $1.70 a foot . It has a very good chance of collapsing with a strong DC. Waste of money. You may find 22 -26 ga there so take a set of calipers with you when shopping. The DC dealers like to sell duct work as sprial or snap lock at very high prices to go with their Cyclones. $4.-$6.00 a foot is common for 6" spiral. You can find a much cheaper source locally made by local HVAC guys. 24 ga is common( and thats a bit thin. 22ga is .033 thick.

They all work except for the thin stuff so buy what fits your pocket book and ignore the hype is my advice. What DC do you have?

[David Helm]

I used HVAC ducting (6 inch). You do have to tape joints (not a big deal) and it works just fine. No issues with "collapse". I think that may be an urban legend; or it was used on a 10 HP system!

[james glenn]

I used HVAC ducting (6 inch). You do have to tape joints (not a big deal) and it works just fine. No issues with "collapse". I think that may be an urban legend; or it was used on a 10 HP system!

David:

I too used the HVAC ducting (as stated above) but mine was 26ga which much of it is and easily obtainable. The really thin stuff is used for dryer vents and such mostly, at least around here. But I agree, it would take some serious suction to collapse this stuff. Heck I sometimes have trouble just getting it to snap together!!!

[Ole Anderson]

At my local HD, they had 26 gauge duct in stock at just over a buck a foot for 6". Watch out as some stock could be 30 gauge, which can collapse. Check your local HVAC supplier for fittings, getting them over the internet can get real expensive. Check this thread:

http://www.sawmillcreek.org/showthre...tall&highlight=

[Joe Shinall]

Thanks guys, I will price this out locally and then price against the astm 2729 and see which is better cost efficiency. I am not going for %100 dust free like some. I just don't have that type of money to put into a bigger DC and other things. Just looking at runs so I don't have to drag over the flex hose to each machine.

[Chris Fournier]

I have found it to be easier to install metal ducting than PVC as you can fudge joints with crimping, fish mouthing etc. The fittings required to go from cyclone to machine are readily available in a myriad of styles and sizes. The metal ducting is lighter when it's all said and done and with spiral duct it requires little support on horizontal runs.

Regardless your efforts improving dust collection will be worth it.

I placed 6 drops in my 1000 sqft shop and terminated each drop with a length of flex hose to hook up to machines as I require. Works well enough for me.

[Rick Potter]

I used HVAC ducting, but I went to a HVAC contractor warehouse. They sold me 26 GA SPIRAL pipe for not much more than HD got for the regular stuff. Comes in 10' lengths. They also have any fitting you can think of.

Rick Potter

[Alan Schaffter]

I have found it to be easier to install metal ducting than PVC as you can fudge joints with crimping, fish mouthing etc. The fittings required to go from cyclone to machine are readily available in a myriad of styles and sizes. The metal ducting is lighter when it's all said and done and with spiral duct it requires little support on horizontal runs.

Regardless your efforts improving dust collection will be worth it.

I placed 6 drops in my 1000 sqft shop and terminated each drop with a length of flex hose to hook up to machines as I require. Works well enough for me.

I find using PVC easier to install. There is no danger of "snake bites" from sharp edges. Plus it is immune from being crushed by suction and impacts and easier to get a perfect seal.

There is a side benefit to having less flexibility making bends with PVC- it forces you to make a better layout. Your goal should be to have as few bends as possible in your runs. I have quite a few feet of duct in my 25' X 38' shop, but have almost no 90's and use gentle 45 wyes, often rotated to 45.

[james glenn]

I used HVAC ducting, but I went to a HVAC contractor warehouse. They sold me 26 GA SPIRAL pipe for not much more than HD got for the regular stuff. Comes in 10' lengths. They also have any fitting you can think of.

Rick Potter

I went to a HVAC supplier as well. Much better pricing and as Rick said, any fitting you can think of.

[Alan Schaffter]

If you go with metal, seal it well. I know they may be cheaper, but avoid "low velocity" wyes (including pant wyes and shoe taps). I've seen photos of layouts here where people have used them. There was a (bad) DC article in the last year or two in FWW where the author used them!!! By adding ducting, most folks are already taxing the ability of their DC to provide adequate CFM at the machines. Don't make it worse by using the wrong components. Low velocity pants and" T" wyes, etc. generate much more turbulence and therefore more static pressure resistance than a reqular (low angle 45) wye. How do you tell the difference? low velocity wyes look like they have webs between the fingers. It is in this open area where the turbulence occurs. Of course never use tight or zero radius bends or 90 degree "T" fittings!!

Regular T wye:



Low velocity pant wye:



Low velocity T/wye:


Shoe tap: