Extraction Ducting - Where to Buy?

[paulrockliffe]

I picked up a somethingorother chip extractor via eBay from a chap whose neighbours were kicking up a fuss about the noise, £50 and something like 2.5hp of suction. It has two 100mm inlets and I acquired 5m of flexible hosing for it.

Since I got it in the summer I've not had chance to do a lot with it, so it's either used with someone holding the end of the hose for me or just for vacuuming up the floor, which it does a great job of!

All of my kit takes standard vacuum cleaner hose, when I tried a step-down adaptor I discovered that the restriction is so severe that it stalls the airflow, the filter bag doesn't inflate and the airflow is lower than my original draper vacuum. So my intention was to make a 3 x vacuum hose manifold so I can collect from a few places at once. That hasn't happened yet.

Anyway, I've built a router table and need to add some extraction to that, I have a rough plan, but wondered where people go to buy ducting pipe etc? I've had a look around the internet, but not exactly sure if I'm looking in the best places. I've been looking at 100mm ventilation ducting, which isn't sold for this sort of thing, but is the right size. Struggling to find long pipe runs though, so there's probably a better place to look.

I'm also considering using some square pipe inside the router table as it'll fit better around my drawers etc and would allow me to drop the pipe out of the bottom. A little unusual, but I'd like to be able to have the option of keeping the table up against the wall while the extraction is hooked up if I can. I was thinking I'd drop the pipe out of the bottom and then run it to one side where an adaptor from square to round can be attached. Another advantage of the square stuff is that it should naturally make a better pick-up at the bottom of the router cabinet.

Any thoughts on the size of hose to run to the back of my fence? 100mm would be too un-wieldy I think.

So generally, I'm after advice on places to buy and whether the square ducting will be fine?

 

[n0legs]

Try these guys on eBay. Here's an item number of theirs, they have a good range of sizes at decent prices 110918247105.
Axminster have a good choice of connections and accessories, worth checking them out.
As for the question about the square pipe, I don't see any reason why it won't work.

 

[paulrockliffe]

Thanks, that eBay link is pretty useful.

 

[paulrockliffe]

Actually, I priced the square stuff up on there, for what I want it's £44.75. I've found the same stuff at Screwfix for £22.31!

I'm looking on Axminster now at bits and pieces; can anyone explain why there's a 63mm pipe standard, when drainage pipe is 68mm? Guttering downpipes are about £33 for 15 metres, compared to £33 for 3.75m in the 63mm that Axminster sell. Makes me wonder whether a 100mm to 63mm reducer would fit exactly inside a 68mm pipe? I notice Axminster do a soil pipe adaptor (125mm) though, so at least that's something.

 

[blackrodd]

Actually, I priced the square stuff up on there, for what I want it's £44.75. I've found the same stuff at Screwfix for £22.31!

I'm looking on Axminster now at bits and pieces; can anyone explain why there's a 63mm pipe standard, when drainage pipe is 68mm? Guttering downpipes are about £33 for 15 metres, compared to £33 for 3.75m in the 63mm that Axminster sell. Makes me wonder whether a 100mm to 63mm reducer would fit exactly inside a 68mm pipe? I notice Axminster do a soil pipe adaptor (125mm) though, so at least that's something.

I've been doing a bit of plastic pipework, the same as you and can only conclude that the 63mm and 68mm pipes are gutter down pipes for different manufacturers so you buy their pipe and fittings.
Swimming pool stuff is different too!, but they do have some nice flexi pipe in their ranges.
Don't forget the pipe can be softened and expanded or contracted by a few mm by careful use of a hot air gun or a good hair dryer, (If you can smuggle it outside). The same can be used for gentle sweeps and bends.
Regards Rodders

 

[paulrockliffe]

Thanks, I've been trying to think of ways of adapting the pipe. I have a proper heat gun after trying to use a hairdryer on some shrink-wrap that protects some wires between the house and workshop that completely failed.

I think I'm over complicating this as I'm going to a lot of work just to move the connection away from the rear of the cabinet, but it'll be worth it. I'm not fully sure how I'll hook up a hose to the fence yet, I could do with a square to round adaptor that isn't for 100mm pipe as an adaptor is going to be a bit ugly. Eventually I'll run ducting round the wall at head height to connect fences and the like into, so I'm not too worried about getting this perfect.

The square stuff being ventilation pipe doesn't seem to be very well fitted together, so is going to leak a bit of suction, but nothing a bit of silicone won't sort out.

 

[sploo]

Paul - is it an impeller based extractor? If so, I believe they're generally high volume low pressure (as opposed to a vacuum cleaner which is low volume high pressure).

At low pressure, I understand that air behaves a little bit like water - in that it doesn't compress well. As such, pulling air through a restricted pipe will really hurt the flow. I.e. you want to stick to 100mm where you can - drainpipe tends to be roughly that diameter, and not too expensive.

This was my solution (made a long time ago, but it still works): http://spikyfish.com/DustExtraction/

Don't miss the link on the page to this useful calculator: http://www.engineeringtoolbox.com/equiv ... d_443.html

Try to minimise the length of run of the flexible hose - the ridges really do kill the airflow.

 

[paulrockliffe]

Wow, thanks for that! That's a really neat setup, though I dread to think how many hours that would take!

Yes, it is an impeller setup, though I think your extractor is more powerful than mine by the looks of it.

It's a great point about the filtering, I should really move the extractor to the coal shed and run a hole through the wall when I do this properly.

 

[sploo]

Wow, thanks for that! That's a really neat setup, though I dread to think how many hours that would take!

Yes, it is an impeller setup, though I think your extractor is more powerful than mine by the looks of it.

It's a great point about the filtering, I should really move the extractor to the coal shed and run a hole through the wall when I do this properly.

The parts were CNC cut, so not too bad. If you have the ceiling height then 6" pipe (or I guess, a pair of 4" pipes) would probably work OK. The only problem with opaque pipe is that it's a nightmare to try to find a blockage (hence the perspex in my design).

My motor is claimed as 3hp IRC, so not massively higher.

A cyclone would be great, but even then I'm told many shops won't try to filter and recycle the air - it's cheaper/safer to vent outside and heat/cool more air for the shop. My garage has so many holes it's basically always at ambient, so there's just no point in trying to filter and return the air to keep it.

With a cyclone I'd have a better system to get the visible dust/chunks into a bin, and then just blow off the fine particles in (visually) clean air. Also, the cyclone would ideally be before the impeller, so instead of stuff running through the blades, it would just be pulling (visually) clean air.

Definitely worth getting it into the coal shed. If you had the height then look at Bill Pentz's site - he's got free plans for making your own cyclonic separator.

 

[gregmcateer]

Most waste pipe manufacturers talk of e.g. 40mm, 50mm pipe, etc, however they actually take their measurements in different ways, so some actually mark on them, e.g. 42mm, some 40mm, some 38mm....
(DAMHIK!!! - Grrrr).

I don't know for certain, but I guess it's to do with internal diameters and wall thicknesses. Suffice to say that certainly for water, (I know not applicable here), just stick to one manufacturer and if you have to mix, then use a plastic compression fitting to join them, (hand tight on a rubber washer - works fine)