Homemade dust collection fittings - anyone got plans?

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Forum topic by petergdenmark posted 05-11-2012 11:50 PM 7166 views 0 times favorited 12 replies Add to Favorites Watch
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55 posts in 2382 days

05-11-2012 11:50 PM


I’ve got a 2,5 HP dust collector with a 5” port. I came with a Y-connector, that is designed to split the 5” inlet into two 4” (i think it’s like the one from Harbor Freight).

Now – i am going to make that into a central system, with metal ducting, and after some experimenting i learned that you ofcourse lose a lot of airflow by reducing the pipe diameter, but also by going up a size, and then reducing down again.

So i elected to buy 5” transparent dust collection hose (damn expensive), thinking that i could always find fittings later. But alas – it’s easy enough to find 5” ducting and bends. But connectors and y-sections and blast gates – not so much. I found one place that would sell one y-connector for $80 which is too rich for me. Seems like the hobbyist standard diameter is 4”, but that reduction costs 30% airflow.

SO – i’ve decided to build my own blast gates, connectors and Y’s from the 12mm phenolic covered plywood that’s sometimes used when casting cement. It’s very slick and very stiff (9-ply hardwood with waterproof glue).

But i would like some ideas and pictures, if anyone has made their own. I found a cool homade blastgate on youtube, but has yet to come up with a slick way of making a quick connect solution for attaching a dust collection hose to different machines, that are not going to get a “hard line”.
Also – when making the Y’s, they are going to have to be rectangular when building them from plywood, but how to connect the round ducting to the rectangular plywood connectors, is the good old square peg – round hole problem. It’s hard to make a really smooth transition, and my fear is, that to many smal corners, nooks and crannies with disrupt the airflow significantly.
Or is it ok to make a 5” box, and just make a 5” hole in the end to accept the duct/hose?

The idea of having to make all kinds of insane compund cuts to make everything smooth is kind of frightening :).

-- I'm from Denmark, but live in Sweden.

12 replies so far

View oluf's profile


260 posts in 3003 days

#1 posted 05-12-2012 12:11 AM

In the U.S. 5” stove pipe is a standard item in any good home Center. You could go to a sheet metal shop and ask them to make you some pipe with pitsberg lock edge. Don’t snap the metal into a tube until you have cut it into the legnths that you need for connections. They could make all your parts for you.

-- Nils, So. Central MI. Wood is honest.Take the effort to understand what it has to tell you before you try to change it.

View Sawkerf's profile


1730 posts in 3032 days

#2 posted 05-12-2012 12:35 AM

How about putting 5” x 6” reducer on your inlet then using 6” pipe and fittings. Some effeciency loss, but the cost of everything else goes way down.

-- Adversity doesn't build reveals it.

View Scot's profile


344 posts in 3360 days

#3 posted 05-12-2012 05:36 AM

6” pipe has worked great for my system.

-- If the old masters had power tools, they would have used them. So get off your damn High Horse.

View petergdenmark's profile


55 posts in 2382 days

#4 posted 05-18-2012 06:43 PM

Thing is – where i live 6” parts are just as common as the 5”, so whether it’s 5 or 6” doesn’t make a difference. It’s just too expensive to buy all the fittings here (a wye connector costs $70), so i am going to make them myself.

I have more time than money, so spending $1000 just for pipes and fittings is not an option :).

There is no sheet metal shop anywhere near here, so i have to be creative.

-- I'm from Denmark, but live in Sweden.

View Gshepherd's profile


1727 posts in 2165 days

#5 posted 05-19-2012 08:26 AM

How about Plastic water/sewage pipe? You can also put a hose clamp on it and heat the ends up a bit and when it softens up tighten the hose clamp.

-- What we do in life will Echo through Eternity........

View Jim Finn's profile

Jim Finn

2647 posts in 2886 days

#6 posted 05-19-2012 08:28 AM

You might try to find a retired sheet metal worker, like me, near you, to show you the shortcut method of making wyes. Books on this subject usually show a long, and more accurate method of pattern development for these fittings but the shortcut method is what is used a lot in the trade. A book by Daugerty and Powell is what was used by me, and most tradesmen ,years ago, to learn pattern development.

-- Website is

View petergdenmark's profile


55 posts in 2382 days

#7 posted 05-19-2012 12:34 PM

Standard plastic sewage pipe is 110mm here – there is no bigger sizes available for the private consumer. So going from 125mm pipe to 110mm pipe means a reduction from 12265 cubic cm to 9500 cubic cm. Thats a 23% loss of pipe size.
I realize that, even though it’s a high volume, low vacuum (HVLP) system, i won’t lose 23% effeciency, since some air acceleration will occur, but 15% of the air flow is about what i think will be lost.

But if i lose the same amount of air, by building my own wye’s out of phenolic, it might be the best option for me – being on an budget and all.

Jim – do you have a link for the book you mention?

-- I'm from Denmark, but live in Sweden.

View Lee Barker's profile

Lee Barker

2170 posts in 2814 days

#8 posted 05-19-2012 02:35 PM

Yet another suggestion: Can you access aluminum roof flashing? With a sheet metal book, some snips and a pop rivet tool, you could learn some new skills and have a lot of fun.

The great part about dust collection is that it’s under suction, so just taping a leak is adequate.

FWIW, I have a professional one man shop and a 2 hp Murphy Rogers DC and everything is reduced from 5” to 4” at the bottom and it works just fine. It serves table saw, planer, edge sander, Grizzly 15” wide belt sander and oscillating spindle sander. I value velocity more than capacity. It’s just dust.



-- " his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View Fred Hargis's profile

Fred Hargis

4951 posts in 2457 days

#9 posted 05-19-2012 02:39 PM

Here's some info that might be useful building the wyes and other fittings.

-- Our village hasn't lost it's idiot, he was elected to congress.

View petergdenmark's profile


55 posts in 2382 days

#10 posted 05-19-2012 03:45 PM

Thank you for the great input.

Well – that settles it.

I will use the 110 mm plastic duct, and fitting that to my 125mm dust collection hose is easy, and a wye only costs $8. The blast gates are pretty easy to make.

Thing is – I like to be able to see and touch the things i buy, so being able to get it locally from a hardware store is great, instead of some online store. Dust collection is allways a work in progress for the hobbyist, so having to plan everything ahead is nearly impossible. It’s a balance between ordering enough so you don’t have to pay $100 shipping again, but not so much that you end up with a bunch of stuff, that you can’t use, but don’t want to throw out either, because you payed good money for it (It’s the same problem if i ordered custom stuff from a sheet metal guy).

You know how it is. You hold on to stuff for years, and eventually you take the hit, and throw it out, only to find that you need it the week after. You never seem to forget the things you throw out, that could have been usefull :).

-- I'm from Denmark, but live in Sweden.

View Jim Finn's profile

Jim Finn

2647 posts in 2886 days

#11 posted 05-19-2012 11:56 PM PAPER:NEW:9781559182942:17.95#synopsesandreviews
This is a link to one of his books. The simplified method is quite simple to do and can be made accurately with some trimming of the pattern after laying it out. All you have to do is lay out ( or trace a pattern) for the hole and fit the branch to the hole and trim to fit. Make simple tabs and seal with caulk.

-- Website is

View AlaskaGuy's profile


4042 posts in 2273 days

#12 posted 05-20-2012 06:45 PM

The may help.

-- Alaskan's for Global warming!

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