Redoing Dust Collection Ducting

[Renzo]

I'm on vacation from work next week (we usually go away this time of year but we've got a sick doggie so staying home, but i digress) so i've decided to redo my dust collection ducting. My original setup was only a temporary solution. I'm going to be keeping the same 1 1/2 hp dust collector but right now i've just got flex tubing running to each machine.

Im going to go with metal ducting. Just have a few things i want to mention/ask.

Is there any advantage to going with anything larger than 4"? I was planning on keeping it 4" to make it simpler (no reducers) and i figured that my dust collector isn't super powerful so if i went with 5" or 6" that ti'd be less efficient.

'm going to be using ducting from an HVAC wholesaler as HD only has 30 gauge, and i want to go with 26, i know that this may generate a few issues with connections and such but that's easy enough to figure out (as per marc's guild video on ducting). I can't find a local source for dust collection specific ducting items.

At some point in the not so close future i may replace the dust collector itself with a cyclone so want to make sure i won't have to redo any ducting at that time if at all possible.

[Renzo]

No idea how this double posted, gah.. sorry

[PurpLev]

sounds like a good plan. I just redid my ducting (actually , just DID as I didn't have anything before) which is connected to my Jet 1100DC. I shopped around and metal duct 6" was ~$400 for my runs, compared to my 4" PVC (ASTM2729) which totalled at just under $100.

4" suffocates the blower and does not efficiently pull and carry the smaller stuff. 6" will work better.

unfortunately for me, $400 was just out of $$$ reach and I had to settle for 4" for now, however whenever we'll get out own place, I'll definitely run everything 6". another thing about metal is that you need to screw all the connections, and I'm a bit concern about that as well, I would probably try to find 6" in PVC. but thats just me.

Since you are doing this with a cyclone in mind - keep the main run 6".

Another thing that I just cannot get around- even if your run is 6", the minute you go 4" on the drops, you are still suffocating your air flow. so unless you have 2 4" drops per machine, you may want to go 6" or at least 5" all the way to the machines.

of course at the end of the day it boils down to what we all can do, and the best we can do it. YMMV.

[Renzo]

Thanks.. My shop is pretty small.. about 15x15 and im getting good pricing on the ducting as my dad used to be an hvac guy and i'm buying from the wholesaler he used to use.

I was just more thinking that the extra two inches would reduce air flow (i.e. 4" will have better air flow/suction than 6")

sounds like a good plan. I just redid my ducting (actually , just DID as I didn't have anything before) which is connected to my Jet 1100DC. I shopped around and metal duct 6" was ~$400 for my runs, compared to my 4" PVC (ASTM2729) which totalled at just under $100.

4" suffocates the blower and does not efficiently pull and carry the smaller stuff. 6" will work better.

unfortunately for me, $400 was just out of $$ reach and I had to settle for 4" for now, however whenever we'll get out own place, I'll definitely run everything 6". another thing about metal is that you need to screw all the connections, and I'm a bit concern about that as well, I would probably try to find 6" in PVC. but thats just me.

Since you are doing this with a cyclone in mind - keep the main run 6".

Another thing that I just cannot get around- even if your run is 6", the minute you go 4" on the drops, you are still suffocating your air flow. so unless you have 2 4" drops per machine, you may want to go 6" or at least 5" all the way to the machines.

of course at the end of the day it boils down to what we all can do, and the best we can do it. YMMV.

[woodcanuck]

I highly recommend Sandor Nagyszalanczy's book on Woodshop Dust Control. It goes into a lot of detail on duct sizes and how to plan out the ducting, wyes and so on.

Here's a link: http://books.google.ca/books?id=uFvMEejhZQ4C&printsec=frontcover&dq=sandor+nagyszalanczy&source=bl&ots=rjPzopZhKn&sig=lBwjGS5gBryiB8l9OWdyy4WZSVE&hl=en&ei=emKKTOelNov_nAf_qv2TCw&sa=X&oi=book_result&ct=result&resnum=4&ved=0CCQQ6AEwAw#v=onepage&q&f=false

I know Lee Valley carries it and I think Marc gets a kick back if you order it via the links off the main woodwhispere site.

[Beechwood Chip]

Bill Pentz has more information on this than you could imagine. Here's the trade-off on duct diameter:

Here's the way I think it works:

• Larger diameter reduces resistance and improves performance
• But, larger diameter reduces air velocity
• If the air velocity gets too slow, then the dust drops out of the air and clogs the ducts

Too big and you lose air speed and get clogs, too small and you put too much resistance and get clogs. I think Bill's site has spreadsheets and formulas that you can use to determine your optimal diameter.

[Renzo]

Yeah i already read through pentz's info for ducting. I'm not any less unsure of what to go with

Bill Pentz has more information on this than you could imagine. Here's the trade-off on duct diameter:

Here's the way I think it works:

• Larger diameter reduces resistance and improves performance
• But, larger diameter reduces air velocity
• If the air velocity gets too slow, then the dust drops out of the air and clogs the ducts

Too big and you lose air speed and get clogs, too small and you put too much resistance and get clogs. I think Bill's site has spreadsheets and formulas that you can use to determine your optimal diameter.

[Chester]

Renzo -

When I did mine last winter, I would have loved to have gone with the 4" duct in metal. But everything that I read said that I should go 6" right up to the machine if possible and then drop to 4" if needed. One solution, if you use 6" and drop to 4" at hookup and feel like the 4" is "suffocating air flow" ... you can simply open a small part of one of your other blast gates.

I used pop-rivets to fasten the metal pieces together and aluminum tape to seal the joints. If I had used screws, the aluminum tape would have had trouble going over the heads. The metal duct runs should be very cheap. It is the metal "laterals" that can get expensive. If you do use 4" ducting, you can use inexpensive black plastic laterals from Peachtree Woodworking (or other sources). But I would still go with 6" if you can afford it.

If you need recommendations for materials, just let me know. I had to collect parts from three different vendors to complete my system.

http://woodtalkonline.com/gallery/album/486/229-dust-collector-install/

Chester

[Vic]

Renzo -

When I did mine last winter, I would have loved to have gone with the 4" duct in metal. But everything that I read said that I should go 6" right up to the machine if possible and then drop to 4" if needed. One solution, if you use 6" and drop to 4" at hookup and feel like the 4" is "suffocating air flow" ... you can simply open a small part of one of your other blast gates.

I used pop-rivets to fasten the metal pieces together and aluminum tape to seal the joints. If I had used screws, the aluminum tape would have had trouble going over the heads. The metal duct runs should be very cheap. It is the metal "laterals" that can get expensive. If you do use 4" ducting, you can use inexpensive black plastic laterals from Peachtree Woodworking (or other sources). But I would still go with 6" if you can afford it.

If you need recommendations for materials, just let me know. I had to collect parts from three different vendors to complete my system.

http://woodtalkonline.com/gallery/album/486/229-dust-collector-install/

Chester

You can get everything you need for ducting from a HVAC warehouse. You want the thicker gauge (I forget what I'd bought, 18 gauge I think).

[NHSchreiner]

I currently use 4" HD type metal duct on two independent 1 1/2"hp Jet and Delta dust collectors. I recently started using both of the dual 4" inlets on the Jet unit and have seen an increase in dust/chip collect capacity. Using only one 4" inlet was starving the collector. I plan on increasing the main run from 4" to 6", with 5" drops to my equipment. I also plan on upgrading the top bag on these collectors with a pleated drum from Wynn Environmental. They also have great links for duct design. You can also look at the Oneida for tips on duct design and sizing.

http://www.wynnenv.com/cartridge_filters.htm

[Chester]

You can get everything you need for ducting from a HVAC warehouse. You want the thicker gauge (I forget what I'd bought, 18 gauge I think).

You have to be a little careful with hvac fittings. The straight pipe is OK because you can orient the male and female ends whichever way you want. But laterals and "y"s have the male and female ends oriented for blowing ... not suction. The WW made mention of this in his last viedo on dust collection in his current digs.

18-guage is very thin. What you want is 26-guage and up if you can find it.

Again, the big $$ comes in those laterals and "y"s.

Chester

[Vic]

You have to be a little careful with hvac fittings. The straight pipe is OK because you can orient the male and female ends whichever way you want. But laterals and "y"s have the male and female ends oriented for blowing ... not suction. The WW made mention of this in his last viedo on dust collection in his current digs.

18-guage is very thin. What you want is 26-guage and up if you can find it.

Again, the big $$ comes in those laterals and "y"s.

Chester

Good point, Chester. The several pieces I bought from my local HVAC were specified without any crimping done. I bought the crimping tool when I installed my system. I got most of my piping from Oneida, which wasn't really that much more expensive than the one off pieces I got from the HVAC warehouse. When I'm speaking of an HVAC warehouse, I'm not talking about and HVAC dealer, rather their supply house.

[PurpLev]

You have to be a little careful with hvac fittings. The straight pipe is OK because you can orient the male and female ends whichever way you want. But laterals and "y"s have the male and female ends oriented for blowing ... not suction. The WW made mention of this in his last viedo on dust collection in his current digs.

18-guage is very thin. What you want is 26-guage and up if you can find it.

Again, the big $$ comes in those laterals and "y"s.

Chester

FYI, 18 gauge is much thicker than 26 gauge. 26 gauge is more than good enough for DC. 30 gauge is the normal HVAC thickness and is indeed way too thin and will collapse under pressure. (lower number gauge = thicker material)

the fittings (Y's, angles and reducers) will definitely pop the prices upwards, but even the straight pipes are much more costly than PVC. to put things in perspective, I got a quote for 6" metal ducting for ~50ft total run (2x~20 runs) which came out to $400 on the money. for lack of funds, I ended up going with 4" PVC which I hope to upgrade at some point if I find scrap duct, or something more affordable to me. my total cost was under $100.

That said - the 4" PVC seems to be OK, although I'm planning on doing some tests and open up the 2nd port on the DC and see how much it will improve performance. If I had my own place and not renting, and I could put something up that I don't have to worry about taking it apart if we move - I'd go the extra $$$ and put all 6" metal, and be done with it.

[Beechwood Chip]

There's really no convenient way for me to use both 4" inlets on my 2HP dust collector, so I'm hoping I can remove the "splitter" on the blower unit and hook a single 6" duct to it. Has anyone done that?

[Vic]

There's really no convenient way6 for me to use both 4" inlets on my 2HP dust collector, so I'm hoping I can remove the "splitter" on the blower unit and hook a single 6" duct to it. Has anyone done that?

I believe I had the option to remove the two four inch ports to reveal the 6 inch port on the old Jet DC1100 I had. I think it was just some screws to remove the 4" port attachment.

[Chester]

There's really no convenient way6 for me to use both 4" inlets on my 2HP dust collector, so I'm hoping I can remove the "splitter" on the blower unit and hook a single 6" duct to it. Has anyone done that?

Chip -

That's exactly what I did. Just removed the 4" splitter with one screw. It exposed a single 6" port and I ran all of my 6" runs off of that.

Chester

[Chester]

FYI, 18 gauge is much thicker than 26 gauge. 26 gauge is more than good enough for DC. 30 gauge is the normal HVAC thickness and is indeed way too thin and will collapse under pressure. (lower number gauge = thicker material)

the fittings (Y's, angles and reducers) will definitely pop the prices upwards, but even the straight pipes are much more costly than PVC. to put things in perspective, I got a quote for 6" metal ducting for ~50ft total run (2x~20 runs) which came out to $400 on the money. for lack of funds, I ended up going with 4" PVC which I hope to upgrade at some point if I find scrap duct, or something more affordable to me. my total cost was under $100.

That said - the 4" PVC seems to be OK, although I'm planning on doing some tests and open up the 2nd port on the DC and see how much it will improve performance. If I had my own place and not renting, and I could put something up that I don't have to worry about taking it apart if we move - I'd go the extra $$$ and put all 6" metal, and be done with it.

PL -

You are correct about the 18-guage. I am a little dyslexic about metal guages. It's the 30-guage that we want to stay away from. I found 26-guage at HD in 4' sections (6") for about $7 each. In my whole system, I probably only used about 10 of the 4' sections.

Chester

[Danny Hellyar]

Renzo,

I know that your probably done redoing your system, but I just wanted to let you and all others in on a few things I've learned from putting together my own system. For those of you who haven't yet tried to do this yourself, it's like anything else , you'll never learn unless you try. My system turned out very well. I have a 3 Hp Grizzly cyclone system and I have all my machines attached to it. It comes out of the machine at 8". I reduced that immediately down to 6". All my main runs are 6" steel spiral ducting. I then reduced all my branch runs to each machine to 5". I even changed all my machine hook ups to a five inch opening. Usually this involved just taking off the 4" inlet( unscrewing it)and making my own 5" inlet from wood and a 5" ducting coupler. It seems that most machines that have 4" inlets can accommodate an additional 1" inlet without having to cut any metal. I went five inch to all my machines except to the smaller ones I did 4", like my bandsaw and drill press. I previously had all these machines hitched up to 4 " and I can tell you that this has made a significant difference in efficiency.

Ok , now here are a few things I've learned that might help you and others in redoing their system. Don't use any mastic type sealing compound to seal the joints. One it's messy and two if you use the stuff that's made for sealing metal ducting you'll never be able to get it apart, unless you saw it off. I wouldn't recommend buying any of the duct or foil tapes at HD or Lowes either. If you need to change your runs or take apart to unclog, they are messy and you can't reuse the tape. The best stuff I've found to use on connecting your joints is a vinyl tape I found at " The Blast Gate Co." They are on the web. They have the best prices on ducting as well. Their prices beat out Penn State, Oneida, and and all other places I've checked. Not only are they less expensive on their ducting but also on their shipping prices. This tape is so good you can wrap your joints with this stuff and take it off two years later an still reuse it and it's only $4.99 for a 150' roll. It will even go over the screws , if you use them, very nicely. I haven't been able to find this tape any where else. They also carry the good self cleaning blast gates, which no one else seems to carry. These are the ones that go all the way thru, so every time you open or close them they clean the gate track out so they always open and close smoothly. I purchase my spiral pipe locally, from an air conditioning supply house, only because it's less expensive when you factor in the shipping of these long pieces of pipe. When I first purchased my dust collection unit, Grizzly said I would only need a one or two horse system but I'm glad I choose the 3 Hp one as my feeling is ,you just can never have to much suction. Kind of along the same lines as never having to many clamps!

[Pete Bennett]

There's really no convenient way for me to use both 4" inlets on my 2HP dust collector, so I'm hoping I can remove the "splitter" on the blower unit and hook a single 6" duct to it. Has anyone done that?

Yep except mine was a four way splitter to 8" on a five horse two bag extractor you will be amazed at the difference. Don't wear floppy underwear or you'll really freak the nosey neighbours

[Bobby]

I have a Jet DC-1100 and removed my 4" splitter (attached with screws) used a 6" main directly to the 6" connection at the collector. Then I split that into two 5" mains.

This way my dust collector was in the middle and each 5" main run was on either side, making each one shorter than a single long run around the shop.

I used 5" mains to reduce the static pressure (resistance to airflow) while keeping the velocity high enough to carry the particles from the machine back to the collector. Be careful of oversizing your ductwork. If you don't have enough CFM the air speed (velocity, measured in feet per minute) will be too slow and heavier particles will settle in your ducts. Also, use wye joints for branches rather than 90 deg. tee joints. For my Jet DC-1100 it works really well at even the last machine on the run. I put most of my heavy dust producers closer to the DC, but didn't compromise my workflow layout just for that.

I used foil tape to seal any leaks and joints I may want to remove later, and brushed on duct sealant on "permanent" joints.

I used some 6" flex at my collector so I can move it around a bit; otherwise I'd break the sealant at the joints every time I changed the bags.

[NotAShakerMaker]

I have used black ABS pipe in the past and loved it. Since ABS was designed for sanitary systems, it has all the fittings you need to build the most efficient piping possible. Plus, there are lots of reducers and adapters to transition to PVC pipe, which is great for that last foot or two when you need to go from solid pipe to flex hose. I used 6 inch pipe for the main line and 4 inch for the drops. For the drops I used the large sweeping curved connections, I think they are called Wye's with 1/8 bend. You can get them with the reducer built in. I installed the Wye's so the drops were straight down and the main trunk line was pitched at an slope of 1/8 inch per foot. When the DC was turned off, you could hear the heavy stuff continue to slide down the pipe and then drop into the Wye's and fall to the bottom of the next pipe.

ABS can be hard to find if your state doesn't allow it for DWW pipe in homes.

Good Luck!

[PeteJr]

To reduce complex ducting and long runs I'm thinking of a second dust collector for the other end of the shop.

Anybody else consider this? Just a thought since my shop is 52 feet long.

[Lawrence Brown]

Well, Kari appears to have 3 dust collectors and 2 shop vacs. At last count, I had 5 shop vacs and a dust collector with a long hose on it.

[PaulMarcel]

I went to Lowe's to price the parts for a long run to the bandsaw that's on the opposite side of the shop. On the way out, I passed the tool corral and saw a Delta DC on clearance for $49. That was an easy decision (and it was assembled to boot!) That sits by the bandsaw and someday when I get unlazy will have a hose to the drill press right next to it.

The thing about rigid duct work is that I tend to rearrange often when something annoys me. That hasn't happened for awhile so the chaos must be at an all-time low, but I used to quite often (and big moves). Having at least one DC on each side of the shop seems much better to me; shorter runs, too. Especially when you see the prices of duct work even the HF 2.0 DC is leagues cheaper than the duct work to get across the garage nicely and you'd get that loss.

[Alan Bienlein]

I did my ductwork for about $120. Bought the straight and elbows at the borg and made the wyes and transitions my self with some free software off the internet. The blast gates and the hanging brackets for the ductwork were all made from scrap lying around the shop.