Dust collection duct sizes

[Bionic Bulldog]

Hi all.
I know dust collection has been discussed many times. I have read many different forums and web pages, and to be honest am still a little confused with all the techno babble.

I have a dust deputy cyclone with 50mm in and out and 2 vacuums. A older numatic henry which i think is 1000w and a B and Q macallister 1800w.

I have 2 saws a dw745 and a ts200 from axminster. TS dust port 50mm Dw looks to be 63mm.hose on both hoovers is around 32mm.

Where i am confused is about what size of duct should i be using from my cyclone to the saws to get the best results. From the vacuum to the cyclone i am fixed to whatever the vacuum hose size is. But should i be keeping the same size out of the cyclone to the saws or upping to 50mm that the cyclone allows to the saw or would that not suck as well. I have no spare duct to experiment and dont want to waste money buying duct which wont be effecient.

Any thought from anyone?. Thanks in advance.

 

[Sideways]

Buy lots of the 50mm black tube they sell for koi carp ponds and use it everywhere, including from the hoover to the cyclone. It's relatively cheap, tough, flexible enough for stationary machines. Basically you are matching the ports on the cyclone. This will allow better airflow than hoover size hose and small offcuts and slivers from the saw will pass through with less likelihood of getting stuck.
If you went bigger - 63mm clear hose all the way - that would provide more of the same benefit, BUT the hoover can only move so much air and the speed of the air slows down as the pipe gets bigger. Slow down the air too much and dust / chips begin to get stuck in the pipe. The isn't enough wind to blow them up vertical sections or around the tighter bends.
I've done the same as you in 50mm and it works with about 6M of pipe run, dust commander and a good hoover. It includes a 1M vertical run straight out of the saw to the ceiling, along and down. I've never had to strip it down to unblock the hose.

 

[Bionic Bulldog]

Thanks for the reply. Out of interest what hoover do you use. I did do a bit of searching on this forum and was considering purchasing the CamVac 2000w or 3000w. Since my workshop is small would likely consider 63mm piping all the way. I have similar issue to others where my workshop is 2/3 of my large garage with the other 1/3 taken up by freezers, dryer, garden equipemnt etc. Even though i have a curtain made up which i can pull across to limit dust getting from one side and covering all the stuff, still some gets through. I know im never going to be dust free, but think my existing hoovers just are not quite up to the job. There fine if i use them on power tools but seem to struggle with table saw. Maybe a camvac for the main outlet and just use smaller hoover on the blade gaurds.

 

[Sideways]

I use an old karcher commercial, no longer in production. Nilfisk's gd900 is very similar. Exceptionally quiet design. I've never heard better. About 1000 or 1200W. Shove the 50mm hose over the outside of the inlet instead of inside it.
If you went with a twin motor, i'm sure that would be great w 63mm hose, you might just want a box to dampen the noise. There are some quite recent threads about that.
Dust extract is a regular topic. You'll find it's (almost) all been covered before. Just use the advanced search

 

[E-wan]

I'm also looking for ducting

Thanks for the suggestion of the 50mm pond tubing it looks really good value.

A couple of other questions my set up won't be very long probably 4 to 5 metres.
- what are the benefits of using solid tubing over a flexible hose

- is it advisable to Earth the setup with a copper wire inside the tubes or is this more important if cutting particular materials or for longer setup. I'll be cutting a bit of plywood but not much else man-made material.

Thanks

Ewan

Sent from my SM-G900F using Tapatalk

 

[Sideways]

The black pond tube is good tough stuff. I'd guess maybe stronger than normal vacuum hose. Certainly a good solid plastic spiral. It's not so flexible so i don't recommend it for extracting hand tools. Fine for machines.

Flex pipe is not absolutely smooth inside. This causes some drag and pressure drop compared to smooth pipe. But some hoses are better than others and joints and bends on fixed pipe are often rather crappy where flex hose can be joint free end to end and allows smooth bends. I don't think there's much in it personally - at least for shortish runs with a hoover rather than a bag type chip collector.

I haven't run an earth wire in or around mine. If you choose to it will do no harm and might help. The only time i observe issues with static are when I cut plastics. The shavings stick to everything !

One last point, my table saw has a partial shroud around the blade below the table. This has a 50mm outlet attached with poor internal design. I connect the extraction to that outlet to take what dust I can straight off the blade. A fair bit still escapes but I've built a simple shallow box to catch the dust that falls into the bottom of the saw. The saw runs much cleaner with the vacuum on than off.
If I had a bigger saw or the dust port was only into the saw body, not this under table blade shroud, I wouldn't get away with a 1200W "hoover".

 

[Robbo3]

Domestic rainwater pipes are nominally 65mm.
There was a paper published some years ago, produced by a university study & backed by the fire service, that stated that there were no known instances of an explosion caused by static in a domestic dust collection system. I can't find it now but this chap seems to have read it
- http://www.thewoodnerd.com/articles/dustExplosion.html

 

[Inspector]

Was this the article you saw?
http://www.woodcentral.com/articles/sho ... _221.shtml

Pete

 

[Robbo3]

Was this the article you saw?
http://www.woodcentral.com/articles/sho ... _221.shtml
Pete

Seems like it might be. Thanks.