Thread: 6" ducting plan

Originally Posted by lovetoride

Thanks Bob. Re baffle box. Would it work just as well if I mounted it on the side of brick base with the inlet at the bottom and outlet/vent at the top - which would be at the bottom of my colorbond at the top of the brick wall (if that makes sense)?

The lower down you can get the exit the better but there's not a bug advantage in it.

So my new shed is up, furniture (benches, drawers) built and the next step is moving the dusty out into the specially prepared enclosure and
running a pipe overhead for dust collection. The dusty is a 2hp Jet.

I have a question w.r.t. pipe diameter: if I go to 175mm length wise -- will there still be enough airflow to transport the chips from buzzer and thicknesser along 6.5m
of pipe, or would 150mm be better? I'm thinking about reducing flow resistance as much as possible, but I can see how one might overdo that aspect.
Would you use 150mm for the droppers or reduce near the top to 100mm hard upvc before going to flex at the machine?
The main line will be about 3m up above the workshop floor.

Currently I am trying to scout out where I can get pvc pipe of these diameters anyhow: no luck at all at the local Bunnings. Nothing bigger than 100mm there.

A general figure of 4000ft/min is often mentioned re the minimum air speed to keep chips etc mobile in a pipe.

If my math is correct:

For 175mm diameter pipe, a CFM of 1035.75 would be required to achieve 4000 ft/min. I doubt the Jet 2hp could achieve that along 6.5m of pipe.

On my fully modified unit, running on 150mm pipe, the best I can achieve through about the same pipe length is 733 CFM not connected to the saw table. This equates to approx. 3750 Ft/min. Once hooked up it drops to approx. 640 CFM which equates to 3260 ft/min.

HTH.

Originally Posted by P.W.H.

I have a question w.r.t. pipe diameter: if I go to 175mm length wise -- will there still be enough airflow to transport the chips from buzzer and thicknesser along 6.5m
of pipe, or would 150mm be better? I'm thinking about reducing flow resistance as much as possible, but I can see how one might overdo that aspect.
Would you use 150mm for the droppers or reduce near the top to 100mm hard upvc before going to flex at the machine?
The main line will be about 3m up above the workshop floor.

Currently I am trying to scout out where I can get pvc pipe of these diameters anyhow: no luck at all at the local Bunnings. Nothing bigger than 100mm there.

Lappa has basically summarised it.

In fact even with the Jet 2HP unless the DC is fully modified (i.e. inlet is converted to 6" and a near 6" connection between impeller and DC , it's near pointless using 6" as you will run into the same problems with sawdust drop out. Its also a bit pointless to use 6" ducting only to drop it down to 4" at the machines. Just like the DC needs to be 6" ALL THE WAY , so do the machine ports.

RE: PVC Pipe, try a plumbing/reticulation specialist store.

Lucky me, the Jet has a 150mm inlet to the impeller, so no fiddling is necessary there.

I've made some modifications to my carbatec jointer's dust chute (just plain awful the way it came, totally open inside the
cabinet the planer it sits on). But I don't see myself mucking about with the bandsaw and the thicknesser to bring the ports up to
6".

I think I'm moderately up to speed now, I've read a lot of your posts here before ... we'll see how it all comes out.

I'm also going to try a sheet-metal/ducting outfit and see how galvanized ducting compares, price wise. Not a clue at this point.

thanks for the responses, -P.

It sounds like you still have some way to go yet.

Originally Posted by P.W.H.

Lucky me, the Jet has a 150mm inlet to the impeller, so no fiddling is necessary there.

The 6" entry port on those DCs is far from optimised, but can be very easily improved using a bell mouth hood.
Read up about them on the forum

What about the connection between impeller and the filter.
Some are 5" and some are 6" .

I've made some modifications to my carbatec jointer's dust chute (just plain awful the way it came, totally open inside the
cabinet the planer it sits on). But I don't see myself mucking about with the bandsaw and the thicknesser to bring the ports up to
6". .

Bandsaws are best serviced using 3 x 4" ducts.
Thicknessers are relatively to fix if they are just extracting from above their cutter head, another ideal place for a bell mouth hood.
Read around on the dust forum to see how its done.

I'm also going to try a sheet-metal/ducting outfit and see how galvanized ducting compares, price wise. Not a clue at this point.

Here in Oz galv is about double to triple the price of PVC stormwater pipe.
The same applies to the junctions - if you can get the galv ones at all.
That's why most people use PVC.
There must be places in NZ, those pipes are worldwide industry standard for plumbing waste and storm water.
It tool me just 10 seconds to fond this
https://www.marley.co.nz/products/pl...tormline-upvc/

I chased up the retail of 150 mm Marely PVC fittings available at Mitre 10 in Nz - OUUUCH!
https://www.mitre10.co.nz/shop/searc...t=marley+150mm
nearly 10X more than Oz prices!!!!
You could import from Oz and be miles in front - galv might indeed be better for you

PWH, Faced with the cost of those crazy NZ PVC junction prices one possibility is to make your own rectangular ducting junctions out of MDF.
Bends are relatively easy and Y junctions are not that difficult.

Here's a post showing how to make a large radius 90º bend
Mens Shed Dust Collection

Originally Posted by BobL

PWH, Faced with the cost of those crazy NZ PVC junction prices one possibility is to make your own rectangular ducting junctions out of MDF.
Bends are relatively easy and Y junctions are not that difficult.

Here's a post showing how to make a large radius 90º bend
Mens Shed Dust Collection

Now there's a thought. I'd never really thought beyond pipe, since all the ports are round..

Originally Posted by P.W.H.

Now there's a thought. I'd never really thought beyond pipe, since all the ports are round..

Ideally a square to round transition would be needed but you will have to reduce from 150 to 120 mm anyway so square cross section tapered reducers shouldn't be too restrictive.

Six inch PVC fittings in NZ are horrendously expensive and hard to find. But I did manage to secure some at a semi-reasonable price. A guy named Andrew at prm.co.nz sells some fittings. I think he goes by the name Tank Guy on TradeMe. So you could try him for some fittings and also the pipe itself.

Gradually making more progress now that I have officially retired!

The dust enclosure is painted and has latches on the doors. I spent today fitting the Soundscreen batts to the enclosure. This was over the sarking/building blanket. A trip to the green shed last Friday resulted in the 16mm mdf purchase for the lining. They cut the large sheets to size for me - no charge as I have no way to neatly cut the large sheets. The guys were wonderful that day with assistance and advice available in several areas!

And just for some fun over the past week or so I made the blast gates and painted them to match the newly painted workshop window sill - because I could.

Oh, and the aircon was finally installed last Thursday although not yet connected. I sure could have used it here during the summer but hey... The sparky will return once I have the enclosure lined so he can install the 15amp outlet.

blast gates.jpgDES and ac.jpginsulation 2.jpginsulation.jpg

Jane