LumberJocks

A Grounded Discussion on Dust Collection Ductwork - Take #2

  • Advertise with us
Blog entry by Lenny posted 03-08-2009 04:05 AM 6607 reads 7 times favorited 15 comments Add to Favorites Watch

This is take #2 on my dust collection ductwork install. Here is the link to my initial blog on this project: “DC-Take #1” http://lumberjocks.com/jocks/Lenny/blog/7465. First, a recap. The space I chose to locate my dust collector (DC) left it in the middle of the 6” ductwork, which I installed at ceiling level. This meant I needed a joint (fitting) that allowed the two sides to meet and enter the separator and DC. I couldn’t find an appropriate 6” fitting but found a 4” double tee so I had to reduce the system before it entered the separator.

Woodchuck and Purplev suggested using a 6×6x6 wye fitting installed vertically instead of horizontally (something I hadn’t thought of) with one 45 degree fitting needed at the top of the pipe coming out of the wye, and two 45s coming out of the top. These connections brought me to the main trunks.

Bob#2 suggested that while doing all this revamp work; I might as well install a couple of blast gates to zone the system in two. Initially I did not want to do this, thinking that for my small shop I didn’t need the extra efficiency this would afford. The more I thought about it though, as Bob said, I would be making the changes noted above, so now was the time to do it. Woodchuck and Purplev, as strong proponents of the least amount of air restriction possible, I think you will be pleased to learn that I purchased blast gates from ClearVue that are installed on the OUTSIDE of the pipe! They fit quite nicely. Blast gates of course raise an issue regarding the ground wire. With a blast gate, your ground wire has to exit the pipe, go around the blast gate and then re-enter the pipe. No big deal, but another thing to consider as I did the revamp.

On my initial install, I brought the ductwork into the trash can, right in the center of the can. Woodchuck and John Gray were a big help in helping me redesign this. I elongated the hole so that the (now) 6” pipe enters the can at a sharp angle such that it is running along the inside of the can. This will help create the cyclone effect needed for the separator to be effective.

My DC has a 5” flange just before the impeller. I needed something 5” coming out of the can that I could join to the flange with a short length of 5” flexible hose. I purchased a 5” hose connector from Grizzly. The picture on their site led me to believe that its length would be about 7”. Upon receipt, I learned it is only about 5” long, i.e., it is only as long as it is wide.

Some of this sits above the lid and accepts the 5” flexible hose. The rest extends below the lid, into the trash can, but only about 2 inches. This model DC came with a Y fitting to connect flexible hose to the DC. It has a 5” top that connects to the flange and has two 4” legs so you can connect one or two flexible hoses. Since I would not be using this fitting, I sawed off the 4” legs, leaving me with just the 5” top at a length of about 4 inches. On the underside of the lid, I slid this over the hose connector and connected it permanently with a couple of screws. This extends the entire piece into the can about 6 inches.

Below is a picture of the inside of the separator after I ran a piece of pine through my thickness planer, making pretty aggressive cuts. I think just about all that was cut from the pine board ended up in the trash can; so it appears to be working as it should.

Lastly, the flange just before the impeller has a crisscross of metal that I imagine Delta puts there as a safety feature to prevent larger objects such as a small tool from reaching the impeller.

The thing is, I feel it substantially restricts air flow. My use of this system will involve attaching one end of a flexible hose to a machine and the other end to one of four drops. As such, the only thing going through the system will be woodchips and dust. I did not include a floor drop into which I can sweep debris and I plan to continue using a shop vac for workbench, floor and other cleanup activities. Are you folks okay with my having removed those metal “crosshairs” or do you think they should have stayed? Thanks for stopping by and thanks again to Woodchuck, Purplev, Bob#2 and John Gray for helping me improve this system.

Lenny

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



15 comments so far

View Todd A. Clippinger's profile

Todd A. Clippinger

8790 posts in 2766 days


#1 posted 03-08-2009 05:05 AM

With the trash can acting as a separator, you are avoiding the damaging chips or strips of wood that the cross barrier is protecting the impeller from. Without the trash can separator, those damaging pieces would go straight into the impeller without the barrier.

Your set-up looks pretty nice.

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

View Beginningwoodworker's profile

Beginningwoodworker

13342 posts in 2340 days


#2 posted 03-08-2009 05:05 AM

Nice set up.

-- CJIII Future cabinetmaker

View Trailer_man's profile

Trailer_man

9 posts in 2034 days


#3 posted 03-08-2009 05:37 AM

1. You will get a better cyclone affect if you cut the pipe end in the can at 45 degrees.
2. I wouldn’t worry about the “criss cross metal” and it’s affect.
3. I question the effectiveness of 6” diameter system with what appears to be a motor in the 1 to 1-1/2 hp range. I like to think of situations in the extreame. What if you had a 12” pipe? The velocity of the air would be too little to convey the material. I think you will need to up the hp to get conveying flow. Type in “dust collection velocity” and research the web. I believe Wood magazine did an article of this subject. One site, http://www.airhand.com/designing.asp has some information.
4. When looking at the system, the 4” tee is the main constriction (assuming you have the necessary flow for 6” pipe. At that point everything might as well be 4” ductwork. Take a look at furnace ductwork as an example. The ductwork always gets smaller as the line gets farther away. The reverse is true with a vacuum system. The website I mention above shows the same thing. The reason it gets bigger is because of the additonal air of an additional branch. The power source must be able to keep the velocity of the largest pipe at its minimium critical velocity. If it doesn’t the chips will drop in the 6” section and never make it to the can.

The other question is since you probably will never run multiple quipment at the same time why go with larger pipe? I have never had anything of wood get stuck in 4” smooth or corrigated tubing.

Sorry to be a downer. As an engineer I am always looking for what can go wrong. The quality of the construction is excellent and sturdy. Remember bumping up the hp can solve a number of inefficiencies. The quality of the construction is excellent and sturdy.

View Lenny's profile

Lenny

1261 posts in 2194 days


#4 posted 03-08-2009 06:13 AM

First, I struggled greatly with Photobucket today and got so frustrated I deleted all pictures and started over. I now realize that this deleted the pictures that were on the first blog and added one that doesn’t belong there. I might make the effort to fix things tomorrow.

Thanks Todd and Charles. Much appreciated. As for you Trailer Man…you’re killing me! I am just kidding. I appreciate your comments and the time you took to offer them. I am just cringing at the thought of a suggestion to change the system yet again! I used the word “discussion” in the title of this blog and I have a feeling once Woodchuck, Purplev and Bob#2 chime in, it will be quite a discussion. It was their input that convinced me to go with 6” pipe all the way to the separator. They didn’t instead suggest changing the 6” pipe to 4” pipe. My shop is quite small, 8’x 18’ so there isn’t a long run of ductwork and with the system now zoned, the DC is only pulling dust through half of the system at a time. I find the suction to be great at the furthest drop on either leg of the system. I think (and hope) it will be fine. Thanks for the suggestion about angling that pipe inside the trash can and I will also look at the site you inserted. Anyone else want to comment on Trailer Man’s position on this? Do you think the 1 1/2 hp DC I have is sufficient for 6” pipe?

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

View Trailer_man's profile

Trailer_man

9 posts in 2034 days


#5 posted 03-08-2009 06:34 AM

Lenny,

You know what? Like you said if it is working that is what counts. I wouldn’t change anything now. I know I wouldn’t have the time or money. I would satsified and start building something with it. It really is good construction and solid.

View Lenny's profile

Lenny

1261 posts in 2194 days


#6 posted 03-08-2009 06:39 AM

Thanks Trailer Man. I do have a woodworking project I should have completed 2 months ago that I put on hold for this workshop project.

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

View Woodchuck1957's profile

Woodchuck1957

944 posts in 2431 days


#7 posted 03-08-2009 06:59 AM

Lenny, that looks pretty darn good, the only thing I would change is the pipe in the lid of the can, it should be in the center of the lid or as close as possible to center, and I would extent it down to atleast 10”-12” total. The reason I say to stay in the center of the lid is that a cyclone is supose to act like a cyclone, the debri is supose to follow the container walls round and round while the exiting air gets sucked up through the center. But who knows maybe it will work the way you have it. Do not cut the side pipe, leave it just the way it is, the ducting looks good also. Have you tried it yet ?

View Lenny's profile

Lenny

1261 posts in 2194 days


#8 posted 03-08-2009 02:50 PM

Thanks Woodchuck. Yes, I did do a test run of the system. One of the pictures above shows the debris left in the separator after I ran a pine board through my thickness planer a few times. I had not fully emptied the plastic bag so I can’t tell if any material ended up in it. I did glance over at it while the board ran through the planer but I couldn’t visibly see material going into the plastic bag. After a bit more use, I will know for sure. If necessary, I can make the small adjustments you suggest.

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

View PurpLev's profile

PurpLev

8476 posts in 2315 days


#9 posted 03-09-2009 04:23 PM

touche! looks great!

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

View Trailer_man's profile

Trailer_man

9 posts in 2034 days


#10 posted 04-22-2009 03:00 AM

Lenny,

Any updates? Everything collecting to your satsifaction? Thanks.

View Lenny's profile

Lenny

1261 posts in 2194 days


#11 posted 04-22-2009 03:32 AM

Trailer Man, I am very satisfied. I have been using the system on a regular basis (tonight for example) and it seems to be working quite well. The bottom 1/8th of the trash can is covered in chips and sawdust and the plastic bag has a substantially smaller amount in it. That indicates to me that the system is functioning properly. I am glad I took Bob#2’s advice and broke the system down into two legs. It is far more efficient to only have air traveling along one side of the system at a time. I’d say this is a done deal. Thanks for checking in on me!

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

View ND2ELK's profile

ND2ELK

13495 posts in 2441 days


#12 posted 12-27-2009 05:37 AM

Hi Lenny

Great looking dust collection system! Job will done! Sorry I missed it till now. Thanks for posting.

God Bless
tom

-- Mc Bridge Cabinets, Iowa

View HokieMojo's profile

HokieMojo

2103 posts in 2395 days


#13 posted 06-15-2010 10:08 PM

Lenny,
Thanks for posting this. I’m thinking about building some similar components myself and I think this will be very helpful. I want to build a separator that sits below the motor side of the unit just like yours. Just out of curiosity though, where did you get that thick piece of flexible hose? I can find 4” but not anything thicker without it costing a fortune via amazon. Just curious as to whether you have a good source. Regardless, thanks so much fortaking the time to blog this. Very educational!

View Lenny's profile

Lenny

1261 posts in 2194 days


#14 posted 06-16-2010 02:43 AM

HokieMojo, thanks for the comments. I have good news and bad news. The bad news is I bought 10 feet of it via Amazon! The good news is, I ended up sharing lengths of it with other LJs. John Gray asked me the same question you did and I sent a section to him. He reimbursed me the cost of mailing it. One other LJer inquired about it and I just sent it to him asking that he do a kind deed or random act of kindness to someone as payment. If you’ll do the same, PM me with a mailing address I will send a section to you. How long a piece do you need? I sent about 15-20 inch lengths to the other guys.

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

View HokieMojo's profile

HokieMojo

2103 posts in 2395 days


#15 posted 06-21-2010 08:50 PM

Lenny,
Sorry for the late response. Anytime someone answers a question I have, I try to respond promptly but somehow this thread fell off the first page of my “pulse” page and I lost track of it. That rarely happens. I’ll PM you after I can take a look at my setup one more time for the length, but I think it would even be less than 15” you mentioned. Thanks for the offer and I’ll let you know!

Have your say...

You must be signed in to post the comments.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase