Jharry

Dust Collection Pipe Suggestions

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Hi all,

I'm getting ready to install dust collection duct in my shop and looking for advice on type and gauge of metal HVAC duct to use. Im not really intending this question to be about different materials types and static/safety/etc since I've pretty much decided to use metal duct instead of PVC. I know this topic has probably been covered to the point of nausea but I can't seem to find a post with information on what gauge to use and where to get it.

My obvious source choices right now are just lowes or Home Depot and I'm guessing the stuff there probably isn't beefy enough. I'd also prefer to not have to buy online. If anyone lives in the Denver CO Metro and know of a good supply source open to public, that would be great.

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If your dead set on the hvac metal pipe make sure you leave enough air leaks or get as thick as you can find. I did the same, my system lasted a few minutes before it collapsed and I rebuilt with pvc. You can buy it at home depot or penn state ind.

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Thanks for response. I guess I'm not completely dead set on metal, just thought it would be easier to install and cheaper. Have a 2hp single stage collector and should always have one gate open.

What's the lightest PVC gauge that can be used. Would the thin wall drainage pipe work? Think I saw metal spiral pipe in Marc's shop but not sure where you get that other than online.

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==> HVAC duct

Please don't use HVAC ductwork -- most folks who go that route are unhappy with the results...

 

With ductwork, you get what you pay for -- full stop*.  

 

• 26g Snap: ($220 per drop) - $220 is the absolute minimum and only for lower-pressure systems (included for reference only -- not recommended).

• 24g Snap: ($250 per drop) - $250 is the absolute minimum for higher-HP systems (my recommendation if you want to save a few $$).

• 24g Spiral: ($350 per drop) - $350 is the heaver-duty solution (my recommendation).
• Norfab Qlock: ($425 per drop) - $425 is the high-end solution (is really nice if you have the extra $$).
 

Where folks get into trouble is hanging 25g HVAC ductwork (Box Store Standard).  High likelihood of of collapse with 3HP or larger cyclone...

 

*Note: Ductwork costing is ballpark and provides basic guidance for the average small shop.

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If done properly you can use the snap loc from the home centers. You do not need to leave any leaks in the system to keep it from collapsing!

 

I bought my snap loc from home depot and lowes and am running a 5hp 16" impeller system with no problems and can close every blast gate if I so chose.

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==> HVAC duct

Please don't use HVAC ductwork -- most folks who go that route are unhappy with the results...

 

With ductwork, you get what you pay for -- full stop*.  

 

• 26g Snap: ($220 per drop) - $220 is the absolute minimum and only for lower-pressure systems (included for reference only -- not recommended).

• 24g Snap: ($250 per drop) - $250 is the absolute minimum for higher-HP systems (my recommendation if you want to save a few $$).

• 24g Spiral: ($350 per drop) - $350 is the heaver-duty solution (my recommendation).

• Norfab Qlock: ($425 per drop) - $425 is the high-end solution (is really nice if you have the extra $$).

 

Where folks get into trouble is hanging 25g HVAC ductwork (Box Store Standard).  High likelihood of of collapse with 3HP or larger cyclone...

 

*Note: Ductwork costing is ballpark and provides basic guidance for the average small shop.

 

Where are you getting these numbers from?

 

I did my whole system for just over half what you quote for one drop in 26 g snap loc and thats what I used.

 

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==> running a 5hp 16" impeller system with no problems and can close every blast gate if I so chose

 

You may be the exception that proves the rule...

Who's 5HP cyclone?

Do you have a schematic of your ductwork layout?

 

 

==> I did my whole system for just over half what you quote for one drop in 26 g snap loc and thats what I used.

You did an entire central DC setup for less than $100 a drop -- all in?  How big a shop? Using who's ductwork?

 

I could see a small shop with all 4" inlet tools, plastic blast gates, small diameter main trunk and all runs under 20' -- yea, maybe.

But blast gates, flex hose, clamps, aluminum tape, etc all add up...

Metal blast gates alone are $25-$30 each.

Wye branches are $25-$35 each.

Long-radius elbows are $10-$15 each

Reducers at $10 each

That doesn't leave a lot for pipe, drops, flex connects, clamps, etc.

You run any length of 8" duct for your main trunk, and the cost gets up there pretty fast.

 

 

==>Where are you getting these numbers from?

Just order of magnitude budgeting tool -- think these are from Air Handling Systems. I think my ductwork was in that range...

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Mine starts as a 8" main that splits into two 6" runs that feeds into a Pentz designed 20" diameter cyclone. The only thing that collapses on this system is the flex if I don't keep two blast gates open. My cost includes everything you see in the pictures. 

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If you are going to use HVAC ductwork, you can get if for 1/3 to 1/4 the cost (or maybe even less) from an HVAC supply like Airtec as compared to Lowes or Home Depot, plus have a lot more boots, and various pieces to choose from. Just go in with a list, and don't waste their time. Just walk up to the counter with your list and tell them that's what you need.  Ask what length the main ductwork straight runs come in, and use the longest pieces you can.   You can go back to get pieces later that you might discover you need.  I use it, but don't have blast gates on anything.  If I had blast gates, it would suck it flat.  You should't have a problem with it for a 2 horse collector.

 

You will also need the pliers to crimp the ends of pieces you have to shorten.  They may be cheaper at Lowes or Home Depot.

 

edited to add:  I found one in Denver with a google search, but it won't let me copy and paste. Do a Google search for "HVAC ductwork supplier Denver Co." and it should come up.  Windtech or something like that.

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I went to Home Depot and purchased the steel 6" heating and cooling pipe and snapped it all together for the overhead run. They have all the reducers to 4" Everything was pop-riveted together, duct taped all the connections, used steel blast gates from Rockler. 

 

I did try to purchase some materials from a heating and cooling supplier but they wouldn't sell to walk-in customers.  <_<

 

-Ace- 

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Here we go again. Yes you can use HVAC pipe, I have it and a 5HP clearview cyclone. If it is running and you close all the blast gates, yes it will collapse. BUT, it is easy to make a small vacuum safety that will pop open for a minute as the cyclone winds down. I used Lowes and Home Depot for mine. I use 6" main, 6" drops and split or reduce to 4" where it is not possible to stay larger. I built a 6" port for my TS, have 6" to within a few feet of the BS where it splits to 2 - 4" lines. All 6" gates are from clearview with micro switches to a relay. Gate open cyclone on, gate closed cyclone off.

Basic idea for the vacuum safety is a 6" x 6" x 6" "Y". It can be any where in the system but the further from the cyclone the better and is easier to tune if it is vertical. Assuming straight part of the Y is vertical, the bottom can continue to any device and used normally. The branch of the Y is connected to the drop or the trunk. In my case I cut a 7" square of MDF with a 6" hole in the middle so it could be secured to the top of the Y, forming a mounting surface. I then took a circle of plywood that fit just right into the pipe. I then glued a rod about half way across the circle plus 1/2", sticking over about an inch on either side. This is the "bearing" and it should be secured loosely to MDF platform. At this point one side should try and drop into the pipe. Screw a block of wood on the lighter side, heavy enough to keep it closed when the cyclone is running and one 4" or larger gate is open. When the last gate shuts the circle will swing open until the vacuum drops and then shut, ready for the next time.

Sorry for the long explanation, the pictures should help. Here it is, maybe I can post it. One file shows it in the open position and the other in the closed position. The "tuning block" is just a scrap, nothing special.

BRuce

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Thank you all for the advice...This community is great! Sounds like I could successfully do it with with the HD/lowes stuff which will probably be the easiest route for me.

Thanks again

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As you start, let me know if you have any questions. This is my second DC install and have learned a lot by doing it twice. First 2 hints are to use metal foil tape for all the joints. Don't use duct tape or the Mylar tape, neither do a good job. next hint is to use 2 90 degree elbows together to make a sweep. It is Harder to get air around a sharp turn and can cause clogs.

BRuce

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Thanks Bruce. Do have a couple questions right off the bat since you offered:). Can you buy wye connections or do you have to build those up yourself? Can't recall if I've seen those at HD. I know penn state sells them. Do you use metal screws, rivets, or nothing (tape)?

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I bought all my wye pieces at either lowes or Home Depot. I don't remember which since I bought stuff at both and it has been more than a year. The fist time I did it I screwed all the connections, this time I screwed very few of them. Mostly just where I needed them to stay in place until I could get the tape on. You may also have some luck with larger hardware stores if your area has one left. The straight sections should be marked with the gauge of the steel, lower is better. 24 would probably stand up without the vacuum safety but all I could find was 30.

I also found I had less noise by adding a 6" piece of flex on the main trunk, just before the cyclone.

BRuce

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If you only support your duct work with a tie wrap or chain then it will collapse unless it is a heavier gauge material. 

 

That is why I made mounting brackets that are a snug fit for my snap loc duct work. I just slide the duct work into the bracket and screw it off to the wall is ceiling just like is shown in my pictures. This is why I'm able to close all blast gates with out fear of collapse.

 

The other thing you need to watch out for on the store bought wyes is that the connections are backwards for a dust collection system. The part that's crimped to go inside another piece of duct work should really be uncrimped with the branch being crimped and inserted into it the wye. This is another reason I made all my own wye connections.

 

Here is a link to the Dust Collector Pipe Joint Template Online Software. http://Dust Collector Pipe Joint Template Online Software

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My duct just rests in or between the trusses. where it does hang, I use the webbing that is used for large flex pipe. I ran all the HVAC duct "backwards" to reduce flow resistance and turbulence so for most of it, there isn't an issue. Where I had a place where it was crimp to crimp, I just cut a 4" piece of duct and joined them. If you are very particular about it, you can tape the side of the joint opposite of the flow before you join it to the other pipe.

BRuce

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Here is a link to the Dust Collector Pipe Joint Template Online Software. http://Dust Collector Pipe Joint Template Online Software

Great link. Thanks. How did you connect your branch pipes using metal pipe? Did you use a sealant?

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Great link. Thanks. How did you connect your branch pipes using metal pipe? Did you use a sealant?

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I only used the metal foil tape specifically made for hvac duct work. I didn't use screws as thats a potential place for debris to catch. 

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You guys are giving up too easily on the HVAC supplier.  I found my invoices.  Not only do they have the best prices, but they have anything you want, or can order it- usually comes next day. 

 

I needed a boot to fit my Grizzly finishing planer.  Opening was 2-1/2 x 12.   2-1/4 x 12 is one of the many standard sizes of boots.  It fit fine.  At first, I thought I wanted an end boot, but it made the end where the 6" duct attaches hang down in the way of the outfeed opening too much.  I just tossed it in the box of spare duct parts, and didn't ask to exchange it for the 3 bucks when I went back to get the side boot.  Cost of the 2-1/2x12x6" side boot was $3.39.

 

 

6" wye was one of the most expensive parts at $9.81

 

6"  5 foot long straight duct   $6.83   2 foot section was $4.01

 

6"  90 degree adjustable elbow  $2.87

 

Wear your working man's clothes, walk up to the counter with your list, and when they ask you for the account number, just tell them it's a cash sale.  Don't call and ask first.

 

You need a license to buy units, and refrigerant, but not for ductwork.

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You guys are giving up too easily on the HVAC supplier. I found my invoices. Not only do they have the best prices, but they have anything you want, or can order it- usually comes next day.

Wear your working man's clothes, walk up to the counter with your list, and when they ask you for the account number, just tell them it's a cash sale. Don't call and ask first.

You need a license to buy units, and refrigerant, but not for ductwork.

Tom,

Many wholesalers can't sell to the public. They can't do taxed sales I am one of them my business licenses does not allow me to take money retail. Most of my lumber suppliers also are wholesale only.

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As far as I know, around here in both Va. and N.C., they all can collect sales tax.  I'm sure it can vary depending on where someone lives, but it's certainly worth the effort to see.  Electrical and plumbing stuff is similarly priced, from those specific suppliers, as compared to the big box stores.  For instance, a roll of wire is a little less than half what Lowes or HD wants for it.

 

My ductwork came from Airtec in South Hill, Va.

 

The places in Richmond that I buy lumber and plywood, and another place that is only flooring, both say they are wholesale only, but I've never failed to drive away with what I wanted in the truck, and I did pay sales tax on it.  When they asked for my sales tax number, I just told them I didn't have one, and it was no problem. 

 

I did have a little trouble from the flooring supplier the last time I went.  They now have policy where they only sell to flooring contractors and not builders.  I told them I had been buying from them when they were at their last two locations (it was true, and I named the locations), and said I actually did all the work building a house myself,  they said, "Oh, okay." 

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As far as I know, around here in both Va. and N.C., they all can collect sales tax. I'm sure it can vary depending on where someone lives, but it's certainly worth the effort to see. Electrical and plumbing stuff is similarly priced, from those specific suppliers, as compared to the big box stores. For instance, a roll of wire is a little less than half what Lowes or HD wants for it.

My ductwork came from Airtec in South Hill, Va.

The places in Richmond that I buy lumber and plywood, and another place that is only flooring, both say they are wholesale only, but I've never failed to drive away with what I wanted in the truck, and I did pay sales tax on it. When they asked for my sales tax number, I just told them I didn't have one, and it was no problem.

I did have a little trouble from the flooring supplier the last time I went. They now have policy where they only sell to flooring contractors and not builders. I told them I had been buying from them when they were at their last two locations (it was true, and I named the locations), and said I actually did all the work building a house myself, they said, "Oh, okay."

You won't do that around here. You may get a little discount at a bigger outfit but not a real wholesaler. The state doesn't mess with wholesalers for that very reason they don't take green money. Makes it easier on accounting for everyone involved and the cost savings is passed on. The one hvac place we have local will not even let you in the door without an account.

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So who collects and pays the State their sales tax?  If the supplier doesn't collect it, does the cabinet maker when he sells to a builder, or a builder when he sells to the buyer, or does your State not collect sales tax on building stuff?    In N.C., everyone pays sales tax on materials when they are purchased, and no one up the chain collects or pays sales tax on house sales.

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