Thread: Rigid pipe for dust collector

Just in case you are not aware, do you realise that using 4" ducting will simply not carry enough air and end up leave most of the fine dust behind in the shed?
I have visited over 30 sheds and examined their dust extraction systems and have not seen a single shed that uses 4" ducting come anywhere near close to taming the dust dragon.
6" pipe is THE minimum that will move enough air to remove fine dust.
That is also only one third of the requirements for dust control.
To fully control dust the DC needs to be able to move sufficient air, and machinery has to be adapted to make use of 6" ducting.

Back to your original question - putting 100 mm hose over a connection means the cross sectional area of the hose will be reduced and this will reduce air flow.
It might not seen like much but it is very significant.
The same applies to all those black plastic ducting fittings available from carbatec and timbecon - avoid those whenever you can and just use stormwater PVC connectors.

It sounds counter intuitive but you want the connection the other way - i.e. PVC connection to go over the hose.
There are rubber connector that do this available from carbatec but they cost $15.

A cheaper solution is a PVC threaded coupler and a threaded cap.
Turn a tight hole in the cap and pull the hose through
Here is a connection with a bell mouth hood on the end.
IMG_2042.jpg

This shows the cross section of the coupler and hose


flexyjunction.jpg

The so called 4" or 100mm pipe is actually 114.1 to 114.5 mm OD. The ID will depend on the wall thickness as there can be up to 4 grades of pipe.

The flex pipe that comes with the dusty or the flexy you buy from Carbatec etc. is designed to go on thin wall metal pipe that is 100mm OD and flexy from most suppliers will be approx. 103 or 127mm

BobL's method is excellent.

If you go to a larger pipe, 150mm pvc has an OD of 160mm and you can buy 160mm ID flexy from Advanced Ducting or Ezi Ducting or once again use BobL's method although WA pipe fitting prices are way cheaper that the eastern seaboard from my experience.

One other point is, in most cases, Poly pipe fitting sizes are the OD not the ID like pvc pipe and fittings.

Originally Posted by Lappa

The so called 4" or 100mm pipe is actually 114.1 to 114.5 mm OD. The ID will depend on the wall thickness as there can be up to 4 grades of pipe.

Minor point but I've never seen 100m @ 114.X mm OD - all the pipes I have seen are

110.20 +/- OD.

The 2HP dust collector I bought has 2x4" inlets, although the Y piece fitting is probably about 6" where it fits onto the machine. My table saw SawStop worksite saw only has a 2.5" outlet same as my Kregg router table. I have yet to solve the dust collection set up for my compound sliding mitre saw. I will be adding a bandsaw and drill press at some stage. Do I make the piping 6" to the machines and then reduce it down to 2.5"?

Cheers Bucky

Originally Posted by BobL

Minor point but I've never seen 100m @ 114.X mm OD - all the pipes I have seen are

110.20 +/- OD.

You are correct in regards to DWV pipe so the OP now has all sizes available. The 150mm DWV pipe they sell near me is very rough on the inside and creates turbulence. Smooth pipes I have available are pressure and electrical which are in the sizes I quoted and not that much dearer. Maybe 100 mm DWV is smooth - I haven't checked. Besides, you can buy large radius bends in Electrical pipe which is better than sharp elbows.

Originally Posted by Bucky

The 2HP dust collector I bought has 2x4" inlets, although the Y piece fitting is probably about 6" where it fits onto the machine.

Most are 5" and a few are 6"
If it's a 5" model it will need to be opened up to be able to take full advantage of the 6" ducting

My table saw SawStop worksite saw only has a 2.5" outlet same as my Kregg router table. I have yet to solve the dust collection set up for my compound sliding mitre saw. I will be adding a bandsaw and drill press at some stage.

This highlights the problem for (especially DIY) woodworkers.

Do I make the piping 6" to the machines and then reduce it down to 2.5"?

It wont help extract much fine dust (it will just leave most of it behind in the shed) but I would encourage you to do the ducting in 6" and connect up to what you have.
Then systemically go around the shed and make the ports on the machines bigger.
There is heaps of info about how to in this forum.

Before asking any more questions here I suggest reading right through at least the following threads
1) The sticky on the generic 2HP DC at the top of the forum
2) How to improve dust ports on machines Improving machine cabinet dust ports
3) Making 150mm dust port connections on machines Making 150mm DC ports for workshop machines

Some of the threads older than ~2010 or so has a number of misconceptions in it so be careful about taking advice from older threads.

Originally Posted by Lappa

The 150mm DWV pipe they sell near me is very rough on the inside and creates turbulence. Smooth pipes I have available are pressure and electrical which are in the sizes I quoted and not that much dearer. Maybe 100 mm DWV is smooth - I haven't checked. Besides, you can buy large radius bends in Electrical pipe which is better than sharp elbows.

About 7 years ago I checked out a bunch of different ducting (mainly DVW) from different suppliers and most if it was smooth to very smooth.
One supplier (a sort of a budget/salvage yard) had some 100 mm DVW with sub mm high lumps up to about 10 mm in diameter on the inside.
I have only ever purchase Stormwater in the 150 and 225 mm size and it has always been very smooth, it's what I make the BMH's out of.

Heres the comparable prices per 6m from pipeline

150 mm"
Pressure $97
DVW $69
Storm $47
No conduit price available.

100 mm:
Pressure $50
conduit $43
DVW $28
No stormwater price available

One benefit of using stormwater/DWV, especially suspended in long lengths is it weighs up to 50% less than pressure or conduit.
Ay the mens shed we have more than 50m of ducting suspended from 12 points on the roof line, if we had use

The DWV I purchased is much heavier than stormwater.
The wall thickness on the stormwater is approx. 3.3 mm and the DWV approx 4.3 mm

The pictures below show the wall thickness plus the "dimpled" surface in the DWV pipe. The DWV has the blue wall centre.

IMG_0621.jpgIMG_0625.jpgIMG_0624.jpg

I have mentioned in a previous post re the heaviness of the DWV and how I wished I had used stormwater but at the time I knew DWV elbows were better re flow than stormwater and not knowing the difference in the pipe weight, I just ordered DWV everything

The one thing is the ID of the DWV I used is closer to 150mm than the stormwater which is approx 152/3 mm. This makes a difference when I used 150 mm metal adaptors for connections to table saws and router tables etc. - I didn't have to pack the gap.

So my recommendation now would be stormwater pipe and DWV elbows - hindsight is a wonderful thing

Pipe works great and is far more efficient than the flex hose in terms of velocity losses to friction. You will find that hard vacuum duct is a whole lot less expensive than pipe.... Just make sure all the joints are sealed with tape and mastic like you would do for ac duct.

The design of the system is also pretty important - as every 90 and tee you add cuts the amount of suction you have.

In terms of size - its all based on the size of your dust collector. You need to maintain a certain velocity inside the pipe or the dust and wood chips will lay down inside the pipe even though you are pulling plenty of air.

I would check with the manufacturer and see what size ducting they recommend and if they have pointers/recommendations for simple system designs.

Originally Posted by Lappa

The DWV I purchased is much heavier than stormwater.
The wall thickness on the stormwater is approx. 3.3 mm and the DWV approx 4.3 mm

30% sound right but I guess it depends on your definition of "much".
It's not much compared to the difference between Storm and pressure where the difference is ~100%

I have mentioned in a previous post re the heaviness of the DWV and how I wished I had used stormwater but at the time I knew DWV elbows were better re flow than stormwater and not knowing the difference in the pipe weight, I just ordered DWV everything

The one thing is the ID of the DWV I used is closer to 150mm than the stormwater which is approx 152/3 mm. This makes a difference when I used 150 mm metal adaptors for connections to table saws and router tables etc. - I didn't have to pack the gap.

All the IDs of the DWV and the Storm water fittings, and ODs of the DWV and Storm water pipe, from Pipeonline all fit each other. This is done so that he does not have to keep every single fitting in stock especially because in most cases it is permitted to use DWV in place of Stormwater. this makes mixing and matching easy. Come to think of it , over the years I have purchase a few 150mm DWV and Stormwater fittings from other places and cannot recall any fitting problems between different manufacturers pipes and fittings but it would not surprise me if it existed.

The main difference between the DWV and stormwater fittings is that the stormwater usually have shorter over lap at the pipe joins than the DVW fittings but that does not matter when this stuff is used for dust extraction systems.

The prices of the DVW fittings are not always dependent on whether something is DWV or stormwater but often depend on the number they sell.

For the 150mm fittings I've tended to purchase the stormwater; Y's and Y reducers, level inverts, threaded couplers, bends of 45º or less,
Fo the 100 mm fittings there are fewer stormwater fittings available so one has to buy more of the DWV fittings
The only thing I buy deliberately purchase in DWV are the 90º bends because of their longer radius of curvature.
But sometimes when restricted for space a really tight 90º bend helps and that is available in stormwater.

Originally Posted by truckjohn

I would check with the manufacturer and see what size ducting they recommend and if they have pointers/recommendations for simple system designs.

Unfortunately here in Australia most manufacturers are not much help and we have had to help ourselves in this regard.