Thread: PCV pipe and flexible duct size

Here's a simple and tidy way to connect to 150 mm PVC pipe.
There are no clips or screwdrivers needed to connect and reconnect, and it can be easily re-sealed with a spare screw cap.
OK, it's not the cheapest but it works it's easy to swap flexies between various ports/machines etc with this method

It involves using a threaded coupler and a screw cap.

I have some soft jaws on one of my WW lathe chucks that I use to hold the screw cap while turning a hole with a beveled edge.
Turn the hole so the flex fits tightly and has to be worked through the hole - my experience that it needs to be opened right out to the internal seal of the screw cap.
Pull enough flexy through so that when the cap is compressed and seals up against the inside of the coupler.



Screwcapjunction.jpg

This is what it looks like in reality.
This is my lathe connection which is movable along the lathe bed.
Flexjoin.jpg

Removal is easy - just unscrew the cap and sealing without the hose is easy and airtight - just screw a regular cap on.

This is the connection for my thicky.
thickyBG.jpg

Clear view also have nice 6" flexy.

I found this to be a problem also. To get around it, I turned up a block of hardwood to be able to shrink down the OD of the pipe to fit the flexy using a hot air gun. I'm running 100 mm at the moment but will be going to 150 when I redesign the shed.
Kryn

Interesting solution Bob. Does that black hose have a 150mm ID or 150mm. OD? That fitting looks like a DWV Access coupling. I'll measure up the ID of a DWV access coupling this week before I order any pipe.

Nice solution Kryn. You managed to reduce the 110 OD to 100mm without any problems? I can buy Flexi to suit ie. 162mm ID but your and Bobl's solutions may be cheaper. Let you know when I get a quote tomorrow.

Originally Posted by Lappa

Interesting solution Bob. Does that black hose have a 150mm ID or 150mm. OD? That fitting looks like a DWV Access coupling. I'll measure up the ID of a DWV access coupling this week before I order any pipe.

The black flexy (its high temp flex cost me $50 for 6m on gumtree) has the same dimensions as the grey one (timbecon), and both have close to same OD as PVC pipe and that's why they cannot be pushed over PVC pipe.
I like this solution better than shrinking PVC pipe down to fit inside the flexy as it maintains the 154mm ID of the ducting all the way.

Yes it is a standard access DWV coupler ($12.50 from pipeonlie), I called them threaded couplers.
There are also stormwater threaded couplers ($8 from pipeline) but they never seem to have them in stock when I need one.

At the mens shed we are terminating some ends of 150 mm PVC duct runs with a 6"-4" Y with threaded ends. The 6" connects to a machine and the 4" is capped, but when needed it enables a 4" flexy to be readily added as vacuuming/cleanup hose.
Yes we could disconnect the 6" and add a reducer but having the 4" threaded port already there makes it much easier.

I went and bought 4 threaded couplings to do the BobL method, but the 6" flex I bought from Stephen at ClearVue Aus turns out to be 153mm ID and slides nicely (tightly) over 150mm DWV. I could not get the stuff to fit inside a threaded coupling. I used duct tape to seal it all up.

Originally Posted by Pearo

I went and bought 4 threaded couplings to do the BobL method, but the 6" flex I bought from Stephen at ClearVue Aus turns out to be 153mm ID and slides nicely (tightly) over 150mm DWV. I could not get the stuff to fit inside a threaded coupling. I used duct tape to seal it all up.

I have piece of Clearvue flexy and Ijust tried it and you are right it will not fit inside a 150mm threaded coupling, but it is so tight in the hole in the endcap that it does not need to go down inside the coupling and seals on the end of the coupler thread.
Makes it a bugger to turn the cap though. - might open up a threaded cap a bit more and see if that helps.

The Clearvue stuff is nice because it's transparent and super flexible but I also found it tears easily which is why I have stuck with the black stuff which is much more robust.
At the mens shed we have the Carbatech stuff which is also a bit delicate.

Originally Posted by Pearo

I went and bought 4 threaded couplings to do the BobL method, but the 6" flex I bought from Stephen at ClearVue Aus turns out to be 153mm ID and slides nicely (tightly) over 150mm DWV. I could not get the stuff to fit inside a threaded coupling. I used duct tape to seal it all up.

Maybe I'm missing something here but 150mm DWV pipe is actually 160mm OD so how could a flex pipe with 153mm ID fit over it - must be very stretchy - does it have a wire coil? Just asking.

Bob, your lucky having pipeonline in WA. Their prices kill anything over here. I can actually buy 150mm FF elbows and pay $15.50 freight and land them cheaper than I can buy them here from distributors such as Reece, Hardware and General etc. in Sydney.
Same as the 125mm pipe - got quoted $184 from one supplier here and pipeonline is $74.50 but freight killed it.

I recently bought some very flexible 6" hose from Major Woodwork Equipment Flexible Hose 6'' - Major Woodworking Equipment
It wasn't for a dust application, but for use on a portable air conditioner which had strange sized fittings to duct the exhaust air out of a window. A sacrificial plastic flower pot with the bottom cut out of it and then split down the length and pop rivetted together in a suitable cone shape for one end, and a small plastic bucket with the bottom cut out plus a bit of gaffer tape and I was in business. It didn't look real pretty, but is very functional.
Sorry, no photos, it was a quick job for a rented house installation for my daughter.

Alan...

Originally Posted by Lappa

Bob, your lucky having pipeonline in WA. Their prices kill anything over here. I can actually buy 150mm FF elbows and pay $15.50 freight and land them cheaper than I can buy them here from distributors such as Reece, Hardware and General etc. in Sydney.
Same as the 125mm pipe - got quoted $184 from one supplier here and pipeonline is $74.50 but freight killed it.

I find this strange. Their primary customers were mining companies who paid whatever it took, especially when they're in a rush, so prices in WA for all manner of stuff were "stupid" during the mining boom. Although the boom has gone prices haven't change that much. They must be doing OK because I notice they have 2 more staff in the sales/office than they had 2 years ago. They like me because I recommend them as a place WA men's shed should look at to purchase ducting.

I also use pipeonline here in Perth. They are helpful and their prices are sensible. I don't bother trying anywhere else these days.
As for ducting..... I use 150mm PVC (either stormwater or DWV fittings) and purchased the 6 inch grey flexi duct from Timbecon. I just poke the ducting into the female 150mm PVC fitting and seal it with gaffa tape or packaging tape. I've made each piece of equipment duct inlet to be a male fitting so I just move the female flexi duct end to wherever I need it.
My thanks to BobL and others on this forum who have provided great information on the issue of dust extraction.
Here's a couple of photos of my setup....20161207_091145.jpg20161207_091212.jpg20161207_091241.jpg

Nice set up Harry. I have a 2hp unit and having seen the size of the 150mm pipe that arrived today, I'm wondering whether the dusty will handle the job

edit: just realised that your dusty is the same as mine - FM300 2hp - so maybe there's hope for my system

Originally Posted by Lappa

Nice set up Harry. I have a 2hp unit and having seen the size of the 150mm pipe that arrived today, I'm wondering whether the dusty will handle the job

I assume you are modifying it as per the sticky?

Yeah the first time the 6" ducting shows up is a bit but you will get used to it.

The one thing that 2HP owners have to watch out for is when using longer lengths of 6" ducting with a single 4" duct/machine/port on the end of it.
A 2HP DC has limited fan performance at sucking in this situation so when the resulting 400 CFM through the 4" hits the 6" duct the air speed nominally drops to ~2037 FPM which is well below that considered fast enough to hold larger chips is suspension in the air flow.
The recommended air speed is 4000 FPM which a modified 2HP DC can sustain through a 6" pipe provided;
- duct length is short
- junctions are minimal
- the machine connected to it can breathe properly.

It would be advisable to regularly open all gates and let the DC clear away any settled chips.