Dust Collection #1 #1: Understanding the nightmares of designing a small shop dust collection system

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Blog entry by geoscann posted 11-26-2012 09:49 PM 2222 reads 2 times favorited 11 comments Add to Favorites Watch
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Well after months of reading every bit of info i can find on dust collection system design. I,am ready to start putting mine together and i would like to share a few things i think i,ve learned. The first thing is most small shops will use a 2hp or smaller collector or vac which ever one you like best. The next thing is the duct work or piping in most shops use 4” sch 40 pipe because its cheap and easy to purchase. But heres the rub. The 90 deg fittings for this pipe is very restrictive. They tell me one 90 is equal to ten feet of pipe true or not. That’s not the problem. After years of working with a flow bench building racing cylinder heads, theirs a few things that are a constant any time air flows around a corner. It slows down a lot. It also go straight across the port or 90. Air don’t like to turn. This creates low pressure aera in the small side of the 90. This fact means that when trying to carry something like saw dust it drops it going around the corner causing it to plug up your pipes. After some research you can buy 4” sch 40 conduit bends that have a 36” arch you will have to use a little heat to fit them together but they will work. – – – The next thing is connecting machines onto the duct i recommend using Y,s with long 90 for this. Tee,s wont work they do the same thing the tight 90,s do, Cause restrictions, this is something you always need to avoid when planning your system. The next thing is collecting the vast majority your waste at the machine. I know every body knocks the trash barrel separators but they do what their design to do.The 4” pipe these small systems use cannot move the large amounts of waste some of your machine create. plus they plug your bag up in a couple of minutes reducing the vac flow. – – -I recommend installing pvc clean outs so that all the joints can be glued so their sealed. It sure is a shame The people that mfg the dust fittings that everybody sells are not made to slip together and fit right into pvc pipe with out adapters maybe someday!!!! – – – I see a lot of people build and seal up their machines try to suck the saw dust up but if you plug it up to tight you will loose air flow and it will not carry the solids to the collection bins. I recommend installing a water column gauge just outside the vac unit and adjusting your air flow so its as high as you can get it at the machine. After a while you will be able to listen to it and adjust your gates as needed. – – – In closing, design your system with the least amount of 90,s as possible use the longest radius 90 you can get. Seal your joints install clean outs their cheap. use Y,s no tees collect as much of you waste at the machine don’t try carrying all the way to your vac it just causes problems. I will include pictures of my system as soon as its done. – – – Thank you for reading my thoughts Please comment as no idea is not to be explored. – – Note the 4” conduit also has 45 deg and offsets if needed. their reasonable priced.

-- BIG geo ---Occam,s razor The simplist answer is often correct

11 comments so far

View jap's profile


1251 posts in 2052 days

#1 posted 11-26-2012 10:15 PM

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#2 posted 11-26-2012 11:01 PM

Geo something i got to soon,thanks for the heads up not anything im looking foward to

-- Jesus Is Alright with me

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11429 posts in 2838 days

#3 posted 11-27-2012 01:02 AM

Good luck. Looks like you have your ducks in a row.

-- Superdav "No matter where you go - there you are."

View geoscann's profile


258 posts in 2278 days

#4 posted 11-27-2012 01:23 AM

JAP I have read bills site a lot of good info there. But we in our small shops are limited to whats available to use in our shops. Most people dont have the money to invest in a 5 hp our larger dust collection unit or 6 to 8 ” pipe for collection. the small collectors wont run over 5” pipe which is like in possible to get and 6” is to big so we need to work with whats easy to get. that why i wrote this blog. I will continue to build mine and as i try it and tune it and report back with my results. thank you for reading.

-- BIG geo ---Occam,s razor The simplist answer is often correct

View Dallas's profile


3599 posts in 2485 days

#5 posted 11-27-2012 01:38 AM

Geo, I use a 1HP HF collector that I modified slightly to blow into a Rubbermaid trash can, and the outlet is a straight up to the OEM bag.
I used 4” green pipe and poly t’s, y’s and elbows.
My band saw, planer, table saw and miter saw are all withing 9’ of the dust collector.
I also have a floor dust pickup every few feet.

I don’t use blast gates, instead I use a short chunk of green pipe and a 4” Poly cap. It works well since I never have more than one machine on at a time.
The only piece that stays open all the time is the old Craftsman band saw, since it has a 2” dust collection hole and no way to connect. I put HVAC tape around a piece of Sched. 40 pipe to connect it to the port and that gives it a 1 3/4” ID to flow back to a 3” which flows to a 4” final.

Good luck with your set up.

BTW, I don’t have a fancy Thein or Dust Deputy, but I don’‘t get much solid debris in my dust bag either.

-- Improvise.... Adapt...... Overcome!

View DIYaholic's profile (online now)


19620 posts in 2673 days

#6 posted 11-27-2012 01:52 AM

Your blog is very timely, as I will soon be running ducting in my basement shop for my HF 2HP DC. I will be building and installing a Thein Top Hat seperator and metal 4” ducting. I look forward to following along and learning!!!

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View CalgaryGeoff's profile


937 posts in 2480 days

#7 posted 11-27-2012 01:57 AM

I read Bill’s dust collection article while I was searching for a dust collection system. I purchased a clearvue, 5hp, 6” piping, and 15” impeller system. I am very impressed with the system and would recommend it to anyone. It’s a light weight system, very powerful and cleans up my shop very nicely. The cost of the system was around $1300, worth every cent.

I use in on my 8” jointer, 15” planner, 24” double barrel 5” drum sander, 3 1/4 hp router table, table saw, bandsaw, drill press and it is more than capable on each of these machines. It also does a great job on cleaning the floor.

I use a single flexible 6” hose about 30 feet long and move it between machine as required as the vacuum is in a closet. I have blast gates and pipe to plumb each machine but have not gotten there yet.

-- If you believe you can or can not do a thing, you are correct.

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16181 posts in 2358 days

#8 posted 11-27-2012 02:23 AM

Keep the info coming geo…..

-- My mind is like lighting, one brilliant flash, then its gone.....

View geoscann's profile


258 posts in 2278 days

#9 posted 11-27-2012 02:37 AM

DIY I to have a hf 2hp dust collector and from some of my testing its going to work fine not a bad machine for the price. – -GEOFF I would love to have a machine like you have but i cant afford it so i need to make what i have work as efficiently as possable.

-- BIG geo ---Occam,s razor The simplist answer is often correct

View CalgaryGeoff's profile


937 posts in 2480 days

#10 posted 11-28-2012 06:30 AM

I understand. You seem to be taking a very analytical approach to your DC design and layout. I think you are on the right track with yours. Keep corners to a minimum as you know use smooth pipe on your main runs, keep runs from tools to main as short as possible and use minimal connections. Keep filters clean if using any and it’s sounds like you have it figured. One thing you might consider is building one of the portable pail type cyclone collectors to hook up onto your shop vac. Easy to do and very effective power. Check websites for used cyclone bodies and motors. I’ve found both on kijiji. As well as pipe. Sometimes clearvue has sales on items. Their website has tons of DIYers photos of DC systems if you have not checked I’d look. Best of luck.

-- If you believe you can or can not do a thing, you are correct.

View Heilander's profile


5 posts in 2137 days

#11 posted 12-01-2012 11:06 PM

Just starting to set mine up now,think I’ll wait and let you do all the hard work

-- Lathes turn me on

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