PCV pipe and flexible duct size

[Lappa]

I've been looking at buying PCV pipe and ducting to install my recently acquired dusty.
I first looked at 125mm pipe as that was the size of the fittings on the dusty. Only available in Pressure pipe and at a premium price. Near me in Sydney, $145 to $184 a 6m length but in WA $92 for CL12 but transport is the killer ($110). Then comes the kicker - no fittings such as Ys, elbows etc available anywhere for 125mm pipe.

O/K - 150mm 6m $52 and all fittings available.

Flexible pipe at Hare and Forbes, Carbatec and Timbercon available in 100mm, 125mm and 150mm at Timbercon only.
But here's the 2nd kicker. The Flexible hose is true to size as stated but the outside diam of the pipe is not. 100mm has OD of 110mm, 125mm has OD of 140mm, and 150mm has OD of 160mm
Therefore the readily available flexible hoses from the above sources doesn't suit 100, 125 or 150mm PVC pipe so it's off to a specialist flexible duct supplier such as Eli Flex, Eximo etc and that pipe doesn't come cheap.
If someone knows different from what I've found in the last two days, or knows a cheaper supplier of flexible pipe, I'd appreciate it as the cost is rising rapidly:oo:

BTW. I've found a manufacturer of cardboard fibre drums that can make to any height. I'm getting one made to fit to my Dusty instead of the bag OR fitting the bag inside to reduce possible bag damage in my rapidly diminishing workspace.

[BobL]

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.



401446

This is what it looks like in reality.
This is my lathe connection which is movable along the lathe bed.
401449

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.
401451

Clear view also have nice 6" flexy.

[KBs PensNmore]

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

[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.

[Lappa]

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.

[BobL]

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.

[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.

[BobL]

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.

[Lappa]

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.

[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.

[Uncle Al]

I recently bought some very flexible 6" hose from Major Woodwork Equipment Flexible Hose 6'' - Major Woodworking Equipment (http://www.majorwoodworking.com.au/woodworking/dust-units-and-accessories/accessories/mwe-flexible-hose-10/)
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...

[BobL]

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.

[harry wall]

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....401484401485401486

[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:?

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

[BobL]

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 :oo: 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.

[petemacsydney]

i have a little bit of drool in the right hand corner of my mouth right now, lol.
i'm just starting out (after 25 years of pretty much next to no wood working) so i have no budget nor room for a dust system right now, BUT! its great to see these systems available and I've now added this to my wish list!
Until then... the broom rules the shop...

[BobL]

i have a little bit of drool in the right hand corner of my mouth right now, lol.
i'm just starting out (after 25 years of pretty much next to no wood working) so i have no budget nor room for a dust system right now, BUT! its great to see these systems available and I've now added this to my wish list!
Until then... the broom rules the shop...

At least get yourself a mask and open any doors and windows?

[Lappa]

As I said earlier, full modification, if required, will occur at a later date when I have time. In the meantime I will be setting up two full runs in parallel as a bit of an experiment. One will be the 6" system and the other will be a 4" system. The 4" system bits won't go to waste as I have to run some drainage for a new carport and the bits are cheap. A couple of the experiments are with the suction sizing vs impellor design and suction size vs discharge size.

[petemacsydney]

absolutely. i have a 3m 7258 welders half face mask that i use for welding fumes. i just switch out the filters as the welding filters are pretty darn expensive! its a great mask - very big fan of it.

[BobL]

absolutely. i have a 3m 7258 welders half face mask that i use for welding fumes. i just switch out the filters as the welding filters are pretty darn expensive! its a great mask - very big fan of it.

I've had to wear 1/2 face masks at work a few times .
Besides being uncomfortable having a beard meant they not very effective so we ended up going with full air masks - also hot, sweaty and uncomfortable

Before I retired I spent some of time setting up my shed to be as comfortable as possible for both wood and metal work so for welding I installed vented welding booth.

Here is my setup.

The bi-folding doors can wrap full around the hood so that grinding grit is constrained and you can see it also doubles as a small spray booth.
That small wooden tower thing on the bench is a Lazy Susan table for easily turning things on when painting.
The 1600 cfm squirrel cage blower fair whips away any welding fumes - even ZnO if I get slack.
At full speed the blower does pull away too much shielding gasses so I have to slow it down when I'm using TIG.

401556

This booth suits the size of stuff I usually work with but if the welding work pieces are bigger than the booth it's no drama because I have 2 other ways of venting fumes and gasses.

One is the wood working DC system which can pull 1200 CFM and I have another 1200 CFM ventilation fan.
I prefer to not use the DC system for welding fumes as they can gum up the filter bags.

With all 3 fans running I'm venting ~4000 CFM and my shed volume is less than 4000 cubic ft in total.

Hope you can keep the drool to a minimum.

[petemacsydney]

nice. drool contained for now, but only just! i don't have much room so i've just made a big bench on wheels and move it to the edge of the garage door when using it for turning, but most of my welding jobs i do on the concrete floor. unfortunate, but i just don't have the room for a better set up (without permanently moving the cars out - which cant happen). might need to move some kids out of the house to create more space!

[Lappa]

BobL

I was was reading through the Generic 2hp mods and near the beginning, this was stated.

"I also noticed the inner diameter of the area where there are no impeller blades is only 125 mm. This would then be the maximum optimum inlet size for this impeller. Using an inlet bigger than this may not generate the expected flow. While I have it open I might knock up a 6" inlet and see what happens"

Other articles I've read seem to agree that opening wider can in fact be detrimental.

Your tests further on seem to indicate that opening up to 150mm actually improved the flow. Is that correct?

Other papers also mention that the suction side should be one size? larger that the outlet. What's you views on that?

I'm in the process of building a dusty shed and I'm looking at running the pipes this week.
Thanks.

[BobL]

BobL
I was was reading through the Generic 2hp mods and near the beginning, this was stated.

"I also noticed the inner diameter of the area where there are no impeller blades is only 125 mm. This would then be the maximum optimum inlet size for this impeller. Using an inlet bigger than this may not generate the expected flow. While I have it open I might knock up a 6" inlet and see what happens"

Other articles I've read seem to agree that opening wider can in fact be detrimental.

Your tests further on seem to indicate that opening up to 150mm actually improved the flow. Is that correct?

Yes there was greater flow, but don't forget that all my measurements were for minimal resistance air flow.

I'm pretty confident that opening this impeller up to 150 mm will effect (reduce) the performance under resistance.
By resistance I mean dirty filters, long ducting, Many junctions and choked machinery.
This probably why the 2HP is not released with a 6" inlet option as the manufacturer has no control over these resistive aspects of duct extraction and doesn't want people coming back saying the 2HP is a dog.

This effect is best described by what is known as the fan curve.
So even though a generic 2HP can move a lot of air (hence catch a lot of dust) it is limited at doing this only when it as unrestricted as possible.
Once again;
Short ducting runs - no more than ~3m
Minimal auctions, minimal flexy
Ducting ends should be Bell Mouth Hooded.
Machine has to be opened up big time so it can breathe
Keep filters clean religiously
Don't not used a chip catcher.

2HP should work OK on unthrottled situations like lathes and some big belt sanders but will be less effective on machines with built in restriction table saw cabinets and router tables.



Other papers also mention that the suction side should be one size? larger that the outlet. What's you views on that?
I haven't done many experiments on this and all the ones I have done have shown the opposite effect. There may be cases where this is correct but I have never seen one.

[Lappa]

So, if the inlet to the impellor is 5" (as shown in your example in the sticky), it may be better to leave it at 5" and run 5" piping?

Most of the papers I spoke about related to fluid pumps. These papers were from system and pump designers so I would hope they are correct. This larger inlet to outlet ratio is also true on most turbocharger compressors I have examined.

So basically, what you are saying in your summary re 2hp Machines, is they unsuitable for a multiple connected ducting system as I can't see one keeping under the 3 metres ie. manifold plus even one flexible connection.
Cheers

[BobL]

So, if the inlet to the impellor is 5" (as shown in your example in the sticky), it may be better to leave it at 5" and run 5" piping?

Firstly, good luck in finding 5" ducting.

5" ducting under performs for wood dust extraction because the most flow you can get through a 5" duct is ~700cfm (for 4" ducting its ~425 CFM while for 6" its 1250 CFM) whereas ~1000 CFM is recommended for most intense wood dust activities
Remember those flow figures for various size ducting are a max, adding filters longer ducting and junctions and throttled machinery and its downhill quickly from there.

6" ducting on modified 2HP system will get you 850 CFM with needle felt filters and ~925 CFM with pleased filters, Once again its downhill from there which is why a modified 2HP DC fails to really satisfy but is often the best that can be achieved given the limited electrical power available in many DIY Sheds.


Most of the papers I spoke about related to fluid pumps. These papers were from system and pump designers so I would hope they are correct. This larger inlet to outlet ratio is also true on most turbocharger compressors I have examined.

This is related to the fan curve requirements of Turbo chargers. My understanding is that the they are more about pressure (e.g. up to 10 PSI) than flow. It is essential they build up pressure to be able to force air into an engine. While a certain amount of pressure is needed at the outlet to drive cyclones and through filters it's not the main game, Dust extractors only operate up to about 1/2 PSI and it's more about flow.


So basically, what you are saying in your summary re 2hp Machines, is they unsuitable for a multiple connected ducting system as I can't see one keeping under the 3 metres ie. manifold plus even one flexible connection.

Stock 2HP DCs are indeed sub par for almost all DIY operations.

A modified DC could be sufficient for some situations, e.g. a small shed where an occasional wood turner with a Bandsaw and a lathe, provided the two machines are on one side of a wall and the DC on the other.
It usually limits all machines be able to be placed up against a wall

When I say 3m I don't mean 3.00m - if its 3.5m or 4m or even 6m the performance does not fall off the edge of a cliff after the 3.00 m but degrades slowly.
The 3m duct length figure is just a nominal figure or guide - e.g. if one of the ducting arms was a straight 5m them that will have more flow than a 3m duct with a right angle bend in it.
Clever installation can do a lot with 3m, the 3m could be the radius of a circle with the DC in the middle, so in effect the DC system could cover 3m one way and 3m the other.
However, it won't cover placement of large machinery like a table saw in the middle of a large shed - that simply won't work even with a modified 2HP DC.

The same applied to all systems wherethey all have a nominal length guide. For stock 3HP DCs running 6" ducting in I reckon that's about 6m which is still very limiting. My 3HP system connects to my table saw guard via 4m of 6" overhead ducting and then 1m of 4" flexy, while the TS cabinet uses 8m of 6" ducting with 5 right angle bends - It's not ideal at all but its all I can really do. Given I used my TS mainly for cutting Al its not a big dust maker AND I have an additional 2800 CFM of quiet, low power, ventilation I can use to extract fine dust. 1200CFM of this extraction is located immediately above the TS.

Bigger, efficient, systems with more flow can enable much larger trunk lines to be installed that reach much further into a large sheds.
For example, at the mens shed I attend (wood working area is 14 x 7m) we have a 4HP 16"impeller ClearVue. The trunk line is ~14m long and 240 mm in diameter and the branches are up to 4 m long and 6" in diameter. This system works because it is efficient.
OTOH some pro setups just use brute strength e.g. 20" impellers and 20HP Motors, since they are not worried at about the paltry $3.75 per hour that it costs to run such a system.

Most of the risk from wood dust is related to exposure.
If you have a shed and machinery with no dust extraction and only use it and a mask for an hour a month you probably have the same risk as some one with good dust extraction that works in the shed for 40 hours a week.

[legin]

Hi Harry

I have the same thicknesser as yours. I see you moulded the pvc over the existing shroud. How did this work out. Does it get in the way at all.

Legin



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....401484401485401486

[harry wall]

Gee, sorry legin. I have only just seen your post. Yes the dust extraction for the thicknesser works really well and no there is no interference from my moulded additions.

[Tonyz]

5 years 11 months classic :D

[harry wall]

Well you would have to rub in my embarrassment by calculating exact timing. Must have been the mods I reckon..... they must have hidden the thread from me :B.

[GraemeCook]

Well you would have to rub in my embarrassment by calculating exact timing. Must have been the mods I reckon..... they must have hidden the thread from me :B.

I was about to comment that you can sometimes get a quicker response at Bunnings, Harry, but on reflection, I will stay stum.