Steel Ducting for Shop DC

[Izzy Charo]

Hello,
Re-modeling my shop, and just got my Oneida V-3000 DC and am thinking about the ducting. In the past I've used PVC, but wanted to upgrade to steel. The two options I've been investigating are the Oneida snap-lock system (22g), which looks reasonable but perhaps a pain to assemble, and the Nordfab system, also 22g, which looks much, much easier to install, but is also crazy expensive. The other ducting I can find locally is much more flimsy (e.g. 26g). So, what have other folks done? How difficult is it to work with the snap-lock? Anyone think staying with PVC still the best idea?? For reference, it's a home shop...about 500 sq ft. Thanks for the help!
Izzy

[Frank Pratt]

26g spiral is not flimsy at all. If you go snap lock, you'd want 22g. I used all spiral 26g duct & long sweep elbows. The big box stores don't carry anything suitable for dust collection, it's all thin snap lock & tight elbows. I got my duct & fittings from a local HVAC manufacturer/supplier.

Installation was easy. Just cut the duct with a jig saw & put 3 screws in each joint. Mastic duct sealer was used on every joint.

[Dave Mills]

You might also look at the "Nordfab-like" ducting from https://blastgateco.com (https://blastgateco.com/). It's not identical, but close, and a fair bit cheaper.

[Matthew Curtis]

I have used this with my clervue max. I worked good for me.

https://www.grainger.com/mobile/product/GREENSEAM-Galvanized-Steel-Snap-Lock-6EKF0

[Ole Anderson]

Show me any 26 gauge snap lock that has collapsed in a hobby shop. I suppose it is possible. 30 gauge, for sure. My whole shop is 26 gauge snap lock, main run is 7", no problems for nearly 10 years. If you go bigger than 7" and have a system that can draw 10" WC or better, you might want to go up (down) in gauge for the bigger ducts. https://sawmillcreek.org/showthread.php?158878-DC-Steel-Duct-Install&highlight=

[Frank Pratt]

Show me any 26 gauge snap lock that has collapsed in a hobby shop. I suppose it is possible. 30 gauge, for sure. My whole shop is 26 gauge snap lock, main run is 7", no problems for nearly 10 years. If you go bigger than 7" and have a system that can draw 10" WC or better, you might want to go up (down) in gauge for the bigger ducts. https://sawmillcreek.org/showthread.php?158878-DC-Steel-Duct-Install&highlight=

I think you're right Ole. I have a 5 HP collector & 8" duct & the 26g snap lock didn't feel like it would stand up. But for smaller sizes it should be okay

[Jim Becker]

My duct is 26 gage snaplock...mostly from Oneida, but some from HD sold as "stove pipe". I'd love to have spiral or "quick connect" ducting in my next shop, but the snap-lock has performed very well. Getting the fittings right is the more important part of the whole design and operation, IMHO.

[Frank Pratt]

Getting the fittings right is the more important part of the whole design and operation, IMHO.

That's right. The airflow doesn't care if the duct is snap lock or spiral, as long as it doesn't collapse. Long sweep fitting do make a difference though.

[Travis Conner]

You can use 1/2" plywood around the piping to keep it from collapsing.

[Jim Dwight]

I got my 5 inch snap lock from Home Depot because it seemed to be much sturdier than the stuff at Lowe's. I don't think I measured it, however, if I did I do not remember the gauge. But it works. Seems like they might have had two types too with the thinner stuff like the Lowes.

I bought several fittings from "the sheet metal kid" I think he's in Idaho, someplace out west in any event. The wye's needed mastic at the joint but they work and fit the snap lock fine.

[Jim Becker]

Jim, they do carry two types....the standard HVAC at 30 gage and the 26 gage "stove pipe" version, albeit usually only in 24" sections. At HD, I believe they have a silver/grey "logo" color to denote the heavier gage steel. 5' lengths are available from other sources and are more convenient for DC work in many cases.

[Jim Dwight]

I bought 5 foot sections. Maybe I got lucky. In any event it works. Made a bit of sawdust today. Working on a sink base and a base cabinet. Fitting the sink was a pain, nice and big but that doesn't leave much room to support the countertop. But I got it.

[Jim Becker]

I'm guessing that geography matters...in this area, the 'borg doesn't seem to carry the heavier stove pipe in 5' lengths. But I also suspect that there are far less folks who demand it for things like wood burning stoves than in other areas of the country, for example. (And local codes are pretty hard, often requiring the much more expensive double wall products)

[Ole Anderson]

I thought "stove pipe" was normally black (if not stainless steel) not galvanized? Might be a local thing.

[Jim Becker]

I thought "stove pipe" was normally black (if not stainless steel) not galvanized? Might be a local thing.

I've seen it both ways, Ole. Black is clearly for "visible' Installations when used as actual stove pipe.

[Bob Cooper]

Originally I was going to use pvc but the price for 26 gauge metal was much more affordable. I was concerned as I’d never done any work with the stuff. Once I got into it I found it much easier to work with than pvc. The fact that the 90’s are so adjustable and I was able to by wyes without them being crimped was nice. Just had to wait for them to be made. Metal tape, screws and mastic sealed and secured everything solid. Also my tool of choice for cutting was an angle grinder.

[Mike Heidrick]

I have a porch full of spiral pipe. The reason why?I bought some used nordfab, and now I'll never use the spiral pipe again. Nordfrab is stupid expensive but it is amazing, and the ability to reconfigure it is worth its price in gold. Awesome! I'm installing a lot of large pieces of it at about 17 ft in the air and I wouldn't want to be screwing around with spiral ductwork.

[Brian W Evans]

I used 26ga, 5" spiral pipe that was classified as "hobby shop" grade. I got it from Air Handling Systems, which is local to me. The pipe itself is cheap but fittings can add up quickly. The hobby shop grade stuff goes up to 7".

Spiral pipe is easy to work with. There's no crimping - you buy couplers, or some fittings have smaller ends to fit inside of pipes. It's easy to cut with a jig saw and I connected everything with rivets and sealed with foil tape. I recommend a pneumatic rivet gun, which you can get on Amazon for $60 or so.

If I could have found a supplier, I would have investigated S&D PVC, which might have been cheaper. I've done a lot of PVC work for plumbing and I don't think that the metal pipe was any more difficult or time consuming to work with than PVC.

Good luck.

[Andrew Seemann]

I've used snap lock and spiral pipe for dust collection, and have done a lot of work with 6" to 12" Sched 40 PVC for water. Spiral pipe is definitely the easiest to work with of the three for dust collection.

[Thomas Crawford]

I used 26ga spiral pipe. I found it easy to work with using sheet metal screws and/or pop rivets. 7" to the V3000 and dropping down to 6".

I ordered some stuff from blastgateco.com and some from Oneida directly. Most of it I got at a local metal shop. 10' lengths of spiral are nice to get locally rather than pay 100's for shipping.

444762

[Larry Frank]

I have a 5 hp Oneida Gorilla and run using PVC. It is cheap and easy to work with. I bought my DWV PVC at Menards and was able to get 6" pipe and fittings.

Why do I use 6" and not 8" ? One reason is that with some tools, the cfm is low with a 4" port and going into 8" , the velocity drops to low.

[Jim Becker]

Why do I use 6" and not 8" ? One reason is that with some tools, the cfm is low with a 4" port and going into 8" , the velocity drops to low.

Larry makes an important point here...our generally "one person" shops sometimes require a "compromise" to insure adequate performance with our dust collection systems with only one gate open. While I do have 7" coming off my Oneida cyclone, the "main" transitions to 6" from there which works well with a combination of 6", 5" and 4" drops/ports along the way. I do have more than one gate open more often these days while my CNC is running and I'm using other tools, but the design is very supportive of single open ports.

[Ole Anderson]

Why do I use 6" and not 8" ? One reason is that with some tools, the cfm is low with a 4" port and going into 8" , the velocity drops to low. One advantage with steel is that is available in 5" and 7" diameters, when 4", 6" or 8" PVC just isn't the size you need to fit the flow.

[Steve Mathews]

I gave up on the fittings supplied by a local HVAC supplier and purchased replacements from The Blast Gate Co. Their customer service was great and the fittings worked well with the locally purchased spiral duct, which was in 10 ft. lengths. All of the joints were riveted in place and sealed with Blast Gate's vinyl tape. I've had to make a few modifications to the system since its original install and I don't know how the Nordfab system would've be any easier. I'm happy with the spiral duct and Blast Gate combination and would do it again given the choice. The 3 times the cost of the Nordfab system was the deal breaker for me.

[Frank Pratt]

I've had to make a few modifications to the system since its original install and I don't know how the Nordfab system would've be any easier. I'm happy with the spiral duct and Blast Gate combination and would do it again given the choice. The 3 times the cost of the Nordfab system was the deal breaker for me.

Steve, I just don't get what all the fuss is over Nordfab. I've not used it, but have watch a few videos of installation & really don't see how it's that much better than conventional steel fittings. It's a cost thing. I could spend all that money on Nordfab, or I could use steel spiral duct & then use the savings to get a really nice 8" jointer, or enough walnut for several pieces of furniture.

[Jim Becker]

The general benefit to Nordfab and equivalent is "faster" installation and reconfiguration because everything clamps together. The stuff is also very heavy which is suitable for larger DC systems, too. And no taping/caulking to seal. For some folks/firms, that's important and for others, it's not.

For my own purposes, I really love the clamp connections for machine connections that need to be released and changed with some level of frequency or for when one wants to reuse one hose for overhead drops that are positioned for convenience. So if I ever have the opportunity to build a new shop, I suspect that I'd use spiral for the general duct work, but pony up the money for the Nordfab (or similar from Grizzly) connections where they make sense. I have them on my CNC, router table and drum sander drops for this reason and it's been essential at the CNC when something long and skinny gets picked up and gets lodged in the hose near the gate. I can clean it fast and be back to work, yet the connection has zero leaks. For the router table, the hose sometimes gets in the way of something large being processed on my slider, so a quick, positive disconnect gets it out the way. For my drum sander, the machine and hose partially block my lathe...I don't do a lot of turning these days, but being able to move the sander quickly and then put it back quickly is a nice benefit. So again, I favor a hybrid approach by using what works best and most cost effectively while providing what I want and need.

I have seen a large Nordfab ductwork installation in a shop down in VA and it was impressive. The owner does evolve his shop frequently enough that

[Frank Pratt]

Honestly, I don't think doing up a clamp is a lot faster than zipping 3 screws in. The real strengths of the system, as I see it, is the self sealing feature, and a situation where things get changed out on a frequent and regular basis. As far as strength is concerned, I can put all my weight on the 8" 26 ga spiral & it barely flexes

[David Walser]

Norfab may not make sense for most hobbyist’s shops. In a commercial setting, Norfab tends to make a lot of sense. Norfab’s ability to be quickly reconfigured is an advantage that has already been discussed. This advantage potentially applies to both commercial and hobby shops. Suppose you know you’ll be moving your shop across town in a couple of years. Spiral pipe CAN be reused, but not as easily as Norfab. Maybe Norfab would make sense in such a case. Or, suppose you’re in your first phase of building your dream shop. In another few years, you hope to add on phase 2 (which will not be just larger, but will result in rearranging much of your equipment). And, a few more years will bring phase 3, etc. Again, Norfab might makes sense as part of your phase 1 build-out.

In addition to the ease of reconfiguration, Norfab is easier to clean than other ductwork. For most of us, that’s not much of an issue. In a commercial setting, it can be a huge issue. Ducts aren’t just used to remove waste, they’re also used to deliver stuff. In the food industry, such ducts may need to be cleaned very frequently. In the chemical industry, the ducts may need to be cleaned between jobs.

My point is just because a product doesn’t have any appeal to you, doesn’t mean the product has no reason for being. I drive a half-ton pickup truck because I have no need for a 3/4 ton or heavier truck. I don’t tow very often and when I do, the trailer is not too heavy. That doesn’t mean my neighbors are idiots for buying a 3/4 ton truck! The same reasoning applies to duct work. For some of us, Norfab makes sense. I just installed a bunch of spiral pipe because Norfab didn’t make sense for me.

[Frank Pratt]

Norfab may not make sense for most hobbyist’s shops. In a commercial setting, Norfab tends to make a lot of sense. Norfab’s ability to be quickly reconfigured is an advantage that has already been discussed. This advantage potentially applies to both commercial and hobby shops. Suppose you know you’ll be moving your shop across town in a couple of years. Spiral pipe CAN be reused, but not as easily as Norfab. Maybe Norfab would make sense in such a case. Or, suppose you’re in your first phase of building your dream shop. In another few years, you hope to add on phase 2 (which will not be just larger, but will result in rearranging much of your equipment). And, a few more years will bring phase 3, etc. Again, Norfab might makes sense as part of your phase 1 build-out.

In addition to the ease of reconfiguration, Norfab is easier to clean than other ductwork. For most of us, that’s not much of an issue. In a commercial setting, it can be a huge issue. Ducts aren’t just used to remove waste, they’re also used to deliver stuff. In the food industry, such ducts may need to be cleaned very frequently. In the chemical industry, the ducts may need to be cleaned between jobs.

My point is just because a product doesn’t have any appeal to you, doesn’t mean the product has no reason for being. I drive a half-ton pickup truck because I have no need for a 3/4 ton or heavier truck. I don’t tow very often and when I do, the trailer is not too heavy. That doesn’t mean my neighbors are idiots for buying a 3/4 ton truck! The same reasoning applies to duct work. For some of us, Norfab makes sense. I just installed a bunch of spiral pipe because Norfab didn’t make sense for me.

Oh, Nordfab has plenty of appeal to me, but everything has to pass the cost/benefit test to determine if it's right for me. It hasn't done that. If one wants Nordfab just because it's neat stuff, I totally understand that & it's a valid reason to have it. But I haven't found a reason to make it work for me. Ease of assembly/disassembly is not really a reason, because spiral duct assembles/disassembles very easily. I've done a couple of rearrangements of ducting in my shop & at no time did I wish I'd sprung for Nordfab.

If we're in the context of a woodworking shop, then ease of cleaning has got nothing to do with it. The inside of spiral duct is very smooth & doesn't catch dust & chips.

We all have ways of spending our money that may appear to be foolish to others & that's fine. I do it, you do it, but just spend it knowing all the facts & don't make decisions based on parameters that don't apply or are invalid.

[Ole Anderson]

The inside of spiral duct is very smooth & doesn't catch dust & chips.
I haven't seen the inside of spiral duct. What are it's advantages compared to same gauge snap lock? I can't imagine it is any smoother on the inside.

[Frank Pratt]

I haven't seen the inside of spiral duct. What are it's advantages compared to same gauge snap lock? I can't imagine it is any smoother on the inside.

There are 2 kinds of spiral duct. One has the spiral crimp on the inside of the duct, the other on the outside. For dust collection, you want the crimp on the outside. The inside is almost perfectly flat. Of course, snap lock is smoother, you can catch your fingernail on the seam, but just. In the real world, it is not enough to catch dust or chips. I've not had a problem with accumulation, even in the 8" duct, which is almost oversized.

[Jim Becker]

Even with spiral with the "wrong" inside, I suspect the performance will be better than snap ock because the transition between sections will be cleaner. Those end crimps on snaplock are going to have some level of disruption to flow as compared to the very low profile of the sleeves used for spiral. IMHO, of course, and not scientifically proven. :)

[Michael W. Clark]

The advantage of clamp together duct is the reduced installation time. The owner can be running sooner. It’s also very easy to add branches and reconfigure as you grow or needs change.

Spiral should be more than fine for home use. It is not usually recommended for business/ industrial dust collection but I do see a lot of it. Seems like there are limitations on its pressure ratings but probably wouldn’t apply to most home/hobby systems due to smaller blowers. Clamp together is only in 5ft sections so it may need more supports than welded duct which is often 10 ft sections. Can’t remember if spiral meets NFPA or not, the smooth interior type might?

I like Jim’s hybrid approach for home use, I’m going to consider that when I make some changes.

If debating metal or plastic, I would lean toward metal. More size, fittings, and hood options. It can be grounded. Probably less cost for metal unless you are doing all 4” and can get the green S&D pipe.

[Larry Frank]

I used both 4 & 6" S&D PVC and bought it and fittings at Menards.

[Jim Becker]

Spiral should be more than fine for home use. It is not usually recommended for business/ industrial dust collection but I do see a lot of it. Seems like there are limitations on its pressure ratings but probably wouldn’t apply to most home/hobby systems due to smaller blowers. Clamp together is only in 5ft sections so it may need more supports than welded duct which is often 10 ft sections. Can’t remember if spiral meets NFPA or not, the smooth interior type might?

While I have seen Nordfab in some commercial shops, like the one I mentioned previously, almost all of the commercial shops I've been in or have seen photos of have spiral for their large DC network systems. It can be very study stuff and while some pressure is a factor, static pressure remains low. Air flow is what DC works on.

[Frank Pratt]

Spiral should be more than fine for home use. It is not usually recommended for business/ industrial dust collection but I do see a lot of it.

I've seen a lot of commercial shops & spiral is all they use. Never seen Nordfab or any other clamp style duct in a commercial shop.

[Michael W. Clark]

I should have said industrial instead of commercial. We don’t do as much in commercial with our equipment. One of our brands at work is a Nordfab competitor. There is a big market for clamp together duct and woodworking applications are one of the main segments in that market. IWF was one of their main shows to attend.

[Frank Pratt]

When I say commercial, I mean not a hobby shop. I would say that a business that manufactures stuff would be an industrial facility. I this context, commercial & industrial are really the same thing.

[Bobby Robbinett]

Every cabinet or furniture factory that I have ever been in uses nothing but spiral duct. Norfab is significantly more popular with small hobby/semi-small commercial shops than they are with true industrial production facilities. I have spent time in factories all throughout the rust belt and never once seen anything other than spiral pipe.

[Michael W. Clark]

I don't doubt that you still see a lot of spiral in the places you reference, but I promise you the clamped duct is not just being used by hobbyists and small commercial. There are at least (3) companies that supply a similar product, KB Duct (our company's brand), Nordfab, and US Duct. A lot of this gets sold through distributers that are also reps for equipment (woodworking, dust collection equipment, etc) so the ducting gets incorporated as a package with the equipment a lot of times.

I think Nordfab may be part of Nederman and I know they do a lot of commercial/industrial systems with their equipment brands. Donaldson who is probably the largest player in the market for cartridge dust collectors pairs this type ducting with their systems and so do their reps when it is appropriate. I'm not sure what percentage of sales of this ducting goes into woodworking applications, but I know it is significant. Donaldson and Nederman are not seen that often in hobby shops.

The brand I work for (Fisher-Klosterman), we supply equipment (cyclones and scrubbers) into wood processing facilities such as for sawmills, planer mills for construction lumber, plywood, OSB, MDF, wood pellet, wood drying, etc. Most all the ducting connected to our equipment is welded and flanged. They do use some clamped duct on smaller branches now sometimes, but welded is still more the norm for new, but occasionally see some sprial there on old systems. Often these systems are large due to the airflows required so the DC equipment is large and heavy too. These systems can be over 100,000 ACFM, but doesn't compare to steel mills where those systems can be well over 1M ACFM!

I'm not saying spiral isn't used or isn't suitable, we have installed on some applications too, but it is not used near as often as welded or clamped from what we see on a normal basis. Perhaps we are not as involved as heavily in some of these other industries. I know they use a lot of open collectors and Dantherm, Agget, and others do a lot in this market.

IMO, spiral would be considered for light industrial applications where there is no concern with abrasion, corrosion, or excess humidity (like from a dryer). This would fit a lot of furniture and woodworking applications just fine. Clamp together would be a step up for the advantages already discussed, then welded would be the next step up for many industrial applications since you have so much flexibility in gauge and materials and go much larger for the bigger airflows.

[Bobby Robbinett]

I don't doubt that you still see a lot of spiral in the places you reference, but I promise you the clamped duct is not just being used by hobbyists and small commercial. There are at least (3) companies that supply a similar product, KB Duct (our company's brand), Nordfab, and US Duct. A lot of this gets sold through distributers that are also reps for equipment (woodworking, dust collection equipment, etc) so the ducting gets incorporated as a package with the equipment a lot of times.

I think Nordfab may be part of Nederman and I know they do a lot of commercial/industrial systems with their equipment brands. Donaldson who is probably the largest player in the market for cartridge dust collectors pairs this type ducting with their systems and so do their reps when it is appropriate. I'm not sure what percentage of sales of this ducting goes into woodworking applications, but I know it is significant. Donaldson and Nederman are not seen that often in hobby shops.

The brand I work for (Fisher-Klosterman), we supply equipment (cyclones and scrubbers) into wood processing facilities such as for sawmills, planer mills for construction lumber, plywood, OSB, MDF, wood pellet, wood drying, etc. Most all the ducting connected to our equipment is welded and flanged. They do use some clamped duct on smaller branches now sometimes, but welded is still more the norm for new, but occasionally see some sprial there on old systems. Often these systems are large due to the airflows required so the DC equipment is large and heavy too. These systems can be over 100,000 ACFM, but doesn't compare to steel mills where those systems can be well over 1M ACFM!

I'm not saying spiral isn't used or isn't suitable, we have installed on some applications too, but it is not used near as often as welded or clamped from what we see on a normal basis. Perhaps we are not as involved as heavily in some of these other industries. I know they use a lot of open collectors and Dantherm, Agget, and others do a lot in this market.

IMO, spiral would be considered for light industrial applications where there is no concern with abrasion, corrosion, or excess humidity (like from a dryer). This would fit a lot of furniture and woodworking applications just fine. Clamp together would be a step up for the advantages already discussed, then welded would be the next step up for many industrial applications since you have so much flexibility in gauge and materials and go much larger for the bigger airflows.


Thank you for sharing such an informative reply. I would love to find an old or well used outdoor tower style dust collector that I could vent into a large dust pile outside my shop. Something that could handle a whole shop worth of machines (not more than 2 going at the same time if that). I have been looking for a unit like this that is well used and either still usable or needing to be rebuilt. Let me know if you come across anyone who might be letting one go

[Jim Becker]

Bobby, given the economic situation right now because of the pandemic, you may actually see industrial equipment like that start to appear on the various machinery auction sites around the country. It's less likely you'll see that stuff on typical consumer focused venues like CraigsList, FB Marketplace, etc.

[Bobby Robbinett]

Bobby, given the economic situation right now because of the pandemic, you may actually see industrial equipment like that start to appear on the various machinery auction sites around the country. It's less likely you'll see that stuff on typical consumer focused venues like CraigsList, FB Marketplace, etc.

Jim you are definitely right about that. I watch every Craigslist in a 1,000 mile radius. I would prefer not to go through a big machinery dealer as I have found much better deals on used equipment dealing with individuals, auction sites, ect. I find the machinery dealers to be overpriced and not on the same level of negotiating prices. Eventually one will come up. I have missed a few that did come up on Craigslist. I would be willing to drive anywhere in the contin US to get a nice big unit.

[Jim Becker]

No question, buying from individuals is often more cost effective. But the nature of what you want means you're more likely to find it at auction when a commercial shop is liquidated. That's the only reason I suggested watching the auctions..."what you want".