More dust extraction ducting

[Wizard9999]

So as not to further hijack the recent thread on ducting I thought it best to start my own, but if mod's deem appropriate feel free to combine.

I plan to base my extraction on a twin motor camvac extractor, with a 4" outlet (but who knows you may convince me otherwise). There is a very handy sized space under the extension of my tablesaw where it can live. You may recall I have a shelf around two sides of my workshop as the block walls were thicker than the timber frame that sits on them, this is rather conveniently a little over 100mm wide. Therefore, I am thinking that I can route the ducting around the workshop sitting on this shelf for much of its journey, though another 'leg' may go across the ceiling to reach bandsaw, but I am still thinking about this.

My main question is this. The outlet on the Camvac is 100mm, but if I really wanted I would have space to run 125mm (or maybe even 150mm) ducting to within a short distance of my machines. Presumably to do so I would put a, say, 100mm to 125mm adaptor on the Camvac and then an adaptor taking it down to the size of the outlet from the machin in question. As the whole system starts with the Camvac's 100mm outlet, is there any benefit to doing this? My gut reaction is 'no', but having read up a little on the subject I am thinking there may be benefit as suction loss seems to be in large part down to the friction created as the air passes through the ducting and if I am reading it correctly this is reduced the larger the diameter of the ducting becomes.

I am also thinking of using ventilation ducting, rather than ducting marketed as being for woodwork dust extraction as the cost difference is eye watering. I have now found a source of 2m lengths at £5.76 versus Axminster charging about £16 for a 900mm length, even taking delivery into account the saving is worth having. The technical description does say it is for lower pressure extraction, but having exchanged emails with the company selling it the reason seems to be the manufacturer specifies larger diameter ducting for higher extraction, it has nothing to do with the wall thickness of the ducting pipe.

As ever, words of wisdom much appreciated.

Terry.

 

[Rob]

cant help you on that one Terry....my extraction is in the dark ages so I think you're doing the right thing by designing it in at the start like this. I might shed a tear or two to see that shelf "go" though....that took a cuppa, tape and drill/driver like few I've ever seen!

 

[9fingers]

Any reason why you are not using 110mm under ground soil pipe (6m for £13.04 at toolsatan) delivered?

All push fit joints so you can modify layout later if needed.

Bob

 

[old]

If the ventilation duct is thin walled it may not last due to the odd chunk of wood. screws etc sucked up and this does happen the fan in the extractor will be steel to cope with this .100/110 mm duct throughout will do the job .

 

[AndyP]

Or you could have a weekend on the continent and get some 100mm soil pipe which makes connecting things up a cinch.
I could bring some over for you but would need collecting from SE London late in August.

Known over here as tube evacuation d'eau.

 

[Wizard9999]

Any reason why you are not using 110mm under ground soil pipe (6m for £13.04 at toolsatan) delivered?

All push fit joints so you can modify layout later if needed.

Bob

Bob

Subject to the point below, mainly because the Toolstation stuff is only slightly cheaper on the face of it, but as it is sold in 6m multiples will actually be more for the quantity I need. Also, something 100mm would take all the standard fittings for blast gates, etc. without any messing about required.

If the ventilation duct is thin walled it may not last due to the odd chunk of wood. screws etc sucked up and this does happen the fan in the extractor will be steel to cope with this .100/110 mm duct throughout will do the job .

Old

Yes, this is the concern. I did ask one of the retailers for some info and suitability but the answer was a bit woolly. I think I need to ask both Axminster and the ventilation manufacturer a very specific question, i.e. what the wall thickness is.

Icant help you on that one Terry....my extraction is in the dark ages so I think you're doing the right thing by designing it in at the start like this. I might shed a tear or two to see that shelf "go" though....that took a cuppa, tape and drill/driver like few I've ever seen!

Rob

True, but almost all of it will end up behind tools, benches, cupboards anyway, so the loss is less than it may seem today.

Terry.

 

[Rob]

I am but a dinosaur....living in the past Terry

 

[tracerman]

Terry , I think you should go for 110mm sewage pipe as suggested already . Push-fit joints ( with washing-up liquid and a couple of slits in the pipe ends for easy fitting ) . I got my Startrite cyclair 75 back in the eighties ( 1988 ) and had used the underground stuff ever since .
Actually , the exit off the machine is 6" which I reduced down to the 110mm with a rubber reducer . Incrediby , this rubber reducer lasted until last summer , and after shopping around , I replaced it with a METAL cone reducer bought cheaply from Lindab at Mayflower Close , Chandlers Ford , they had a whole range of metal tubing and parts , might be worth a look . But as stated I prefer the underground stuff , I have erected , dismantled and changed my system several times over the years having moved workshop three times and made " improvements " along the way ,

Steve