Thread: Under slab dust extraction

The only point I can think of is to run enough pvc and outlets to allow for multiple changes in your workshop. Excess outlets can be capped until needed.
New tools can mean a new layout.
I've had to reconfigure my workshop a few times because of space limitations as I added new "stuff".

Good luck.

Use 150mm pipe and think about getting a poker in when you use the table saw without turning on the dust extractor and the pipe fills up with shavings.

Thanks for your replies. I'll run with the 150mm and let you know how it works out.

Cheers,
Duncan

The main issue I can think of would be the pipe filling up with sawdust and shavings at the end of the run under the slab, and the extractor not having enough suction to lift them.
When I was researching to build my cyclone, Bill Pentz, said on his site to put any verticle rises at the start of each run , ie- at the machine end, because thats where the most velocity is, by the time the shavings have reached the end of a long run through the pipe they have lost a lot of their velocity and may not be able to be able to be lifted at the endof the run.

When I built mine, I used overhead lines 150mm diameter. with the rise at the machine and the long run back to the cyclone has a slight fall towards the cyclone, it has never had a problem.

If you have a very powerful extractor, or your extractor is below the level of your outlet, this probably wouldnt be an issue, hope this has been of help.

If you havent already I would suggest a read of Bill Pentz's site, lots of good info there.

That's a good point about the need to lift the dust at the end. By the time the 150mm pipe is buried under the slab, it has to lift back up some way, especially with a cyclone type machine where the inlet is at the top.

Great website too - I'll be doing a bit of reading there.

Duncan

Originally Posted by duncang

Great website too - I'll be doing a bit of reading there.

Duncan

Bill is the guru when it comes to dust extraction

Good luck with your project, keep us posted how it's going.

Put some wire mesh in the bottom of your tablesaw, 150mm will not block up if you keep the sticks out... lathes and bandsaws too need a meshed inlet.

A 3hp dusty will do that easy, depending on run lengths and on how you set the dusty up weather its a cyclone or normal(use a pfc filter, not bags)being unrestricted in bends you will lose less to restrictions, this would make up for a riser to the dusty.


Ive got a overhead system in my current workshop, pipes still get in the way and transfer vibration to the tin shed, pvc pipes also attract dust.
Underfloor is the way to go, even if you block its pretty easy to unblock it anyway just push some poly pipe down there(straighten the first foot or so if its curly). I would include a clean out at the end of the main run after any inlets, probably outside the shed.

My new workshop will have the system under the floor along with air and power, but Im going with a suspended wood floor not concrete.

I spoke with Robert from Gregory Machinery at the TWWW in Brisbane over the weekend and he raised a couple of reasons why not to put DC under the slab:
1. Small bend radius on the PVC elbows resulting in extra drag;
2. Static charge build up in the PVC resulting in extra drag (and possible fire risk?);
3. Inability to 'blow out' the pipes at the end of the day resulting in left over shavings becoming a fire hazard;

These points are enough to make me think twice about going under slab, and putting in a proper overhead system

Duncan

1. 150mm pipe and fittings fix that
2. Wife's tale
3. that's more to do with good design