# Dust ducting advice needed



## new2woodwrk (Mar 16, 2015)

I have the HF 2hp collector and I run 4" sewer piping across my ceiling off it (HD piping $7.00 each for 10').

From it I have a 4 -2 " adapter and run 2" flex hose to my table saw - that's about 10' of 2" coming off the main pipe..

I add 20' of 2" hose lengths to reach across the floor when I set up portable tools (the table saw is not connected at this point so it's a straight line with no T's) - they all have 2" connectors.

The question is - I am considering adding an additional 4" 20' section off a T section from the main pipe and drop down with the 5' 2" flex hose.

In essence... Instead of running the 2" for 20', I'd run the 4" for 20' and drop down the 2" for 5'

Basically I'm asking which is better, 20' of 2" or 20' of 4" adapting down to 2" for the connection to the tools?

Also the dust collector has Y outlet port (I only use 1 of the ports and the other is closed off) - would it be better to connect the 2nd line to that or T off the main line?

Hope I didn't confuse the heck out of you - but thanks in advance for any and all advice - it's greatly appreciated


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## UnisawGuy (Jul 20, 2014)

The best thing you can do is scrap the 4" and 2" pipe and start over with 5" or 6" pipe. Then change the ports on your machines to match the pipe. 
http://www.billpentz.com/Woodworking/cyclone/


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## new2woodwrk (Mar 16, 2015)

UnisawGuy said:


> The best thing you can do is scrap the 4" and 2" pipe and start over with 5" or 6" pipe. Then change the ports on your machines to match the pipe.
> http://www.billpentz.com/Woodworking/cyclone/


Thanks for the response - unfortunately that's not really an option at the moment


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## BWSmith (Aug 24, 2010)

Irrespective of diameter,flex...and the more rough,tall the "ribs"...the more it kills airflow.

So anywhere you can get rid of it,the better the systems work.It is a fact of DC,shoplife however.But limiting it's use...for instance,if your setup has to have a bend,coming out of a machine port....then flex is not as bad as it would be in a straight section.Because of the way the airflow is disrupted in the bend anyway.It still isn't as good a smooth bend,just doesn't give up as much as a straight section.

I'm not a Bill Pence groupy,yes he's moved dust management ahead a bit.But applied science is just as valuable as theory when it comes to DC parts.Mr Bill,buys "over the counter" parts.If he'd step UP to the world of fabrication,I'd bet a chicken dinner some of his data would change.

Port design and velocities may look great on computer models,but that ain't the last word.

Look into or for an auto exhaust shop,for metal tubing under 3".Not condemning plastic(well,a little),but metal tube and ducts open up way more options,just sayin.

And,best luck on your system.Got the same blower sitting on the shop floor.Mounting it upside down on shop ceiling(heavy,haha).


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## new2woodwrk (Mar 16, 2015)

Thanks BW - I was doing some research and thought I would start to look into the metal ducting. Before, I was considering running PVC, but I'm liking the metal more and more as there are more options that are less rigid - and it appears less expensive.


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## BWSmith (Aug 24, 2010)

One of the main area's is transitions from larger to smaller diameters,making them MUCH longer than typical,abrupt plastic.It keeps velocities up,with less drag/suction loss.

Also,on these longer transitions is the ability to "branch" directly out of them,vs always waiting for a straight.

Further,though it doesn't seem like a big deal,wait till you have two or more "verts" going up in confined spaces.As when machinery is backed up to one another.We have two shapers this way.Throw in the gates,some ells,and short bits of flex,it's like 10#s of stuff,in a 5# bag thing.The space savings does add up.


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