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A "Grounded" Discussion of Dust Collection Ductwork

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Blog entry by Lenny posted 02-13-2009 01:49 AM 9788 reads 4 times favorited 19 comments Add to Favorites Watch

A couple of months ago, I got a great deal on a Delta 50-760 dust collector (DC). It was used but barely, and I got it for $200. I have a relatively small shop; only 8’ X 18’. Originally I planned to place it outside a shop wall, in my garage, to save on space. However, I found I could fit it in what was a “dead” corner in the shop, sort of tucked out of the way. I decided to run ductwork and thanks to the fine work of fellow LJer, Patrick Jaromin, I had a guide on which way to go. I opted for the 6” green sewer pipe with four 4” drops. There has been much discussion about reducing the drops and to avoid repetition, I will refer you to Patrick’s blog for answers to those questions. For me the biggest challenge was what to do about the junction where the ductwork breaks off in two directions. Based on the corner I selected for the DC, it was in the middle of the ductwork. We know that 90 degree tee fittings are not acceptable for dust collection systems. I found what is called a “double tee” (aka sanitary clean out) fitting. It has two sweeping 90 degree turns. Ideally it would have been 6” on the sides and 4” on the bottom. Even 6×6x6 would have been nice and I could use a reducer at the bottom but I found it is only made in 4” size. I kept searching (googling, etc.) and ultimately found that 6” to 4” adaptors are sold so I decided to go with them. I resolved that my drops were going to be 4” and since I was incorporating a pre-separator (more on that shortly), that would be 4”; I would bite the bullet and allow the ductwork to reduce to 4” just before it headed down into the separator and finally the DC.

After reading several articles and posts about pre-separators (hereafter separators), I decided I wanted to include one. I remain skeptical as to how effective it will be. It seems to me if the DC is as efficient and effective as claimed, it is going to suck up everything that finds its way into the trash can, leaving nothing behind. I can’t see how even the largest and heaviest chips will be left behind, but time will tell I guess. Anyway, the challenge here was that this model DC has a 5” flange for a wye adaptor that comes with it. The wye allows one or two 4” flexible hose connections. With the separator, I would not be using this adaptor. Instead I had to find a 5” connection down to the trash can lid. I did a lot of searching again and eventually found that Delta makes a 5” to 4” reducer and I went with that. I cut a hole in the lid, tight to the 4” side. The flange between the two sides sits on top of the lid. I used silicone caulk inside and out to set the reducer and used a short length of 5” flexible hose with hose clamps to make the connection with the DC .

dge

I wanted to use as little flexible hose as possible but the separator is designed to accept a flexible hose to its side. I decided to bring the 4” ductwork right down to the separator using long sweep 90 degree elbows. The problem then would be how do I remove the trash can from the ductwork to empty it? One night when I was very tired and frustrated, I solicited the brain power of a neighbor who came up with the idea to use a 4” Fernco sleeve. After removing the lid, I just loosen one clamp and slide the trash can over to pull it out and empty it.

Grounding the System

I decided to run a ground wire inside the ductwork. As I installed the pieces, I fed an 18 gauge bare copper wire through. It required me to use electrical connectors at each of the drops. The ground starts at the DC, attached to one of the bolts near the motor. It goes down along the outside of the trash can to a nut and bolt I attached to the side of the trash can after drilling a hole through it.

Attached to that same bolt but on the inside of the can is another piece of copper wire.

That piece runs through the plastic pipe up the wall to the double tee fitting where it marries up to the wire running through the 6” pipe and each 4” drop down to the blast gates. Each drop ends with a long 90 degree elbow fitting and a blast gate. I wasn’t sure how the grounding system was to terminate at the blast gate and then continue via the flexible hose to each machine. A co-worker and new LJer, “Lenzo” came up with a great suggestion. I drilled a small hole behind the blast gate, fed the copper wire through and attached an alligator clip to the wire. I will use a 10 foot length of flexible hose to go from machine to machine. I exposed a small amount of metal at the end of the hose by cutting away some plastic. I attach the clip to this exposed wire.

On the other end of the flexible hose, I find an appropriate spot near the dust port of each machine and attach an alligator clip (permanently) like I did at each blast gate.

There you have it. The system is grounded from machine to the DC.
This was a lot of work and it was challenging to complete. I was bogged down a few times waiting for parts I ordered online to arrive. If anyone decides to take on this project, I suggest you check out the prices on fittings at acehardwareoutlet.com. I found their prices to be far lower than a local plumbing supplier.

-- On the eighth day God was back in His woodworking shop! Lenny, East Providence, RI



19 comments so far

View Beginningwoodworker's profile

Beginningwoodworker

13338 posts in 2324 days


#1 posted 02-13-2009 02:24 AM

Looks nice.

-- CJIII Future cabinetmaker

View Woodchuck1957's profile

Woodchuck1957

944 posts in 2415 days


#2 posted 02-13-2009 02:55 AM

Looks good, but, I think you’d be better off running 6” from the Wye to the can. Just my opinion.

View scarpenter002's profile

scarpenter002

473 posts in 2556 days


#3 posted 02-13-2009 03:11 AM

Lots of work. Please let us know how the seperator works for you.

-- Scott in Texas

View John Gray's profile

John Gray

2370 posts in 2536 days


#4 posted 02-13-2009 05:10 AM

I have the same collector, a Delta 50-760, and a trash can just like yours. I found a 5”i.d sewer connection to use for the lid the problem is finding 5”i.d. flexible tubing that doesn’t come in 10’ rolls for $40 or so, all I need is a foot of hose. Did you find anyplace that sells short lengths of 5” hose?
I like your idea of using the side of the can to enter instead of doing it thru the top. Have you tried the can set up yet? Where did you get that idea? I’m getting ready to make the Paul Thien Collector, http://www.cgallery.com/jpthien/cy.htm ,have you seen it or have any comments on it? I’d like to talk to you about it at your convenience if you could PM me your phone # or I could send you mine
Thanks,
John Gray

-- Only the Shadow knows....................

View Rxmpo's profile

Rxmpo

250 posts in 2396 days


#5 posted 02-13-2009 07:02 AM

Lenny,

This was one heck of a project and you executed it perfectly! Excellent work and great blog. There is a ton of information in here for the rest of us to use. Thanks and congrats on the new system.

Mike

View Lenny's profile

Lenny

1252 posts in 2178 days


#6 posted 02-13-2009 08:05 PM

Thanks for the comments guys; much appreciated.

Woodchuck, I value your opinion. Therefore, I want to throw a question back to you: Given my set up, with the DC in the middle of the ductwork, if you use 6” pipe all the way down to the trash can, what would your fitting be at the critical junction; the one where the ductwork goes in two directions and heads down to the trash can? If it is a 6×6x6 wye fitting it will not be a proper turn from one direction. It would be like a straight tee but with an even worse angle for the air to turn. How would you handle that junction? Thanks.

-- On the eighth day God was back in His woodworking shop! Lenny, East Providence, RI

View Woodchuck1957's profile

Woodchuck1957

944 posts in 2415 days


#7 posted 02-13-2009 08:18 PM

Well first I’ll say thats a nice 4” Wye you found, but if you can’t get the same thing in a 6”, then another route would be to stack two 6” Wyes, point one one direction, and the next one the other direction. Then at the top of the top Wye put a cleanout plug in it. Or one Wye pointing one direction and out the top run a couple 45 degree elbows going the other way.

View PurpLev's profile

PurpLev

8476 posts in 2299 days


#8 posted 02-13-2009 08:48 PM

I’d second Woodchuck – the whole idea of going 6” pipes is to keep airflow from being constraint. reducing it to 4” right before the machine creatres a bottle neck that:

1. constraints air flow (exactly why you want to go 6” all the way)
2. creates torbulance – all reduction rings will do that to some extent.

the good thing (so to speak) is that the reduction to 4” is on the vertical line, so you won’t have an accumulation of dust ‘hills’ at that spot, but in terms of air flow – you are killing it at that point, and since this is the main line, and just before the machine – it’s kind of a shame.

I’d opt to use 1 6”wye going vertical, and splitting to the right (or left), and on top of that put 2 45 degree bends to the opposite side . OR as woodchuck suggested stack 2 whys on top of one another and plug the higher wye with a cleanout plug.

Other than that – really nice job on the plumbing! where did you find those 6” pipes? I’m still in the search for those. and really great idea on the separation can before the DC – cool idea.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Bob #2's profile

Bob #2

3808 posts in 2672 days


#9 posted 02-13-2009 09:00 PM

I would add to these constructive critics that with such a small DC you would have been better to have “zoned” the piping into two separate runs with blast gates.

Bob

-- A mind, like a home, is furnished by its owner

View Lenny's profile

Lenny

1252 posts in 2178 days


#10 posted 02-14-2009 01:51 AM

To Woodchuck and Purplev: [A light bulb appears above my head.] “Eureka, a vertical junction!” Talk about linear thinking (literally). This idea never dawned on me. I only considered a horizontal connection. It took me a few minutes to picture your suggestion but it makes perfect sense. Purplev, your idea even simplifies the junction by requiring only one wye. This is great. I will have to do this. Thanks. This is just one more example of how great this community is. Thousands of minds are better than one. Here are a couple of rough sketches in case anyone (like me) can’t picture the suggestions right away:

Woodchuck’s Idea

Purplev’s Idea

-- On the eighth day God was back in His woodworking shop! Lenny, East Providence, RI

View PurpLev's profile

PurpLev

8476 posts in 2299 days


#11 posted 02-14-2009 02:13 AM

Bob#2 idea is more than valid – placing a blast gate at the first split going in each direction (2 gates) would separate the entire setup into 2 zones that you can block individually to increase air flow to the other zone.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Lenny's profile

Lenny

1252 posts in 2178 days


#12 posted 02-14-2009 02:28 AM

Point #1: Woodchuck, sorry, I just realized that in addition to the two wyes suggestion YOU had also suggested the one wye and Purplev opined that he would go that way.

Point #2: Didn’t mean to shirk your suggestion Bob. It is appreciated. However, you have to remember that this is a small shop and the suction coming out of this 1 1/2 hp (alleged to be 1200 cfm) DC is plently right now, even at the furthest drop. When I eliminate the reduction to 4” and go to 6” all the way to the separator, it will be even greater. I agree Bob, that a blast gate zoning off the ductwork would be more efficient but I don’t think I need that greater efficiency given the size of my shop.

-- On the eighth day God was back in His woodworking shop! Lenny, East Providence, RI

View Bob #2's profile

Bob #2

3808 posts in 2672 days


#13 posted 02-14-2009 02:33 AM

Lenny, I have currently a 2 hp cyclone system. I have had both a 1 hp separator system and a 1-1/2 hp cyclone system.

My current system needs gating to get my the best dust collection.

Let’s talk agian in 6 months or so?

cheers

Bob

-- A mind, like a home, is furnished by its owner

View Todd A. Clippinger's profile

Todd A. Clippinger

8775 posts in 2750 days


#14 posted 02-14-2009 02:36 AM

This is a great blog post. It is full of good information and plenty of pictures and drawings to convey that information.

It looks like you have a nice shop setup.

-- Todd A. Clippinger, Montana, http://americancraftsmanworkshop.com

View Woodchuck1957's profile

Woodchuck1957

944 posts in 2415 days


#15 posted 02-14-2009 03:18 AM

Bob #2 has a point, and while your redoing it all, now would be the time to throw a couple in at the branch inlets. If your a one man shop like I’m guessing a darn good percentage are here, you only need one branch at a time. Plus if I remember right, your DC inlet is a 5”, so useing a 6” line is already pushing it.

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