Sharing the journey – DC system

[Wongo]

I finally got time to do some real work. It took me only 2 evenings to complete this dust system. It was surprisingly simple. Well it was because I had planned it for so long so I knew exactly what to do.

(outback): I bought the 4” blast gates from LV when I was in the US. http://www.leevalley.com/wood/page.aspx?c=3&p=51506&cat=1,42401&ap=1
They are very good and very effective. (Forget about the plastic ones.)

I am very happy with the result. :)

[Wongo]

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[Grunt]

Wongo, you forgot to connect the DC up to the car in the last picture.

Anyway, well done. Thanks for the post.

[Wongo]

Wongo, you forgot to connect the DC up to the car in the last picture.

Anyway, well done. Thanks for the post.

My mother-in-law is not in the car yet. :D

[zenwood]

Welcome back Wongo. Good to see you get straight back into it with some new toys.http://www.woodworkforums.ubeaut.com.au/images/icons/icon14.gif

Is that standard 100mm PVC pipe that the blast gates go into? Are the rubber bands needed to fill out the diameter? Is that a saw cut on one of the pipe ends?

What else didya bring back? Any probs getting tax back in the US, or getting the stuff into Oz?

[Waldo]

G'day Wongo,

I still have to connect all the PVC yet and my idea was to run it a long the floor, partially because the machinery won't be permantly in the same spot - as I have to make room for an office in th shed yet.

I'll be running a 2Hp C/T Dusty 1200 CFM permanatly rigged up to three machines, I like your idea of running all the ducting at ceiling height - less intrusive that way - my question is - do you notice a loss of suction with vertical as opposed to running along the ground? Would my Dusty be able to run as efficiently borrowing on your idea?

Thanks :D

[Wongo]

Is that standard 100mm PVC pipe that the blast gates go into?
Yes

Are the rubber bands needed to fill out the diameter?
Yes

Is that a saw cut on one of the pipe ends?
Yes

Zenwood, I think you have already worked why I did that.



What else didya bring back?
A lot and the bigger ones are LV LA block plane, LA smooth plane, med shoulder plane.

Any probs getting tax back in the US, or getting the stuff into Oz?
No

[Wongo]

do you notice a loss of suction with vertical as opposed to running along the ground? Would my Dusty be able to run as efficiently borrowing on your idea?

No, I think it is a credit to the metal blast gate. :)

[outback]

Bloody well done mate. Makes me a bit green seeing all the nice machines.

MAy I suggest you fit a MIL detector to the pipe end nearest the car, you don't wanna miss any opportunity. :D

I saw those blast gates on the LV site, and wondered if they were the ones you got, they look good, not that expensive either.

[Harry72]

You must have shares in the JET company?
So the dusty system sucks well then ;)

[YAKI]

Good pics. I have to set something up soon so the pics help alot. Just haven't gotten around to setting up the complete system yet!!!

Have a good one.

[fletty]

A Jet (Powermatic) man after my own heart!
I've got one of Jet's DC's that sit on top of a 200litre (44 gallon) drum and exhausts out through a pleated cardboard filter ... it works very well. My set-up, which is about to be changed, runs at ceiling height with flexible droppers to the DC and machines. The horizontal runs also use the ribbed flexibles and I was suspicious that this created huge drag as the sawdust had to be dragged over the ribbed surface.
So, I set up a length of 100mm rigid (smooth) PVC and the same length of ribbed flexible. The smooth PVC was much more efficient at sucking up sawdust especially when the pipe was horizontal.
My new set-up is planned to have 100mm smooth PVC horizontals at ceiling height and ribbed flexible vertical droppers. I have read everything that I could via this forum re static charge and have never had a 'belt' off a length of 100mm PVC that sucked in good Camden air continuously for 12 hours. The 'Mythbuster' episode has convinced me to use the 100mm unearthed PVC.
My shed is a gaden shed on steroids and the 100mm lies very nicely nested into the purlins that run the length of the ceiling with contiuous contact to the purlins.
Will post progress if anyone is interested, Fletty

[Waldo]

G'day Fletty,

I'd be interested as I'm in the process of setting up my own Dusty.

[Skew ChiDAMN!!]

Fletty, what cfm is your DC rated at? And how high above the floor is your horizontal run? I know it's at ceiling height, but I've yet to install the ducting on my 1200cfm unit and I'm wondering how it'll handle the height of my ceiling.

I can't run ductwork at floor level so I'd like to work out how high it can go w/out causing me grief. Naturally I'd like some figures for comparison.

[Dr Dee]

I agree totally re PVC vs flexible. I did similar tests and found the PVC degraded performance far less. One section of my DC plumbing goes 2.7m above floor level to provide clearance over the roller doors and also has quite a long run. For this ection I used 150mm PVC instead of 100mm on the basis that the cross sectional area is proportional to the square of the radius and hence is 2.25 times bigger. This markedly reduces the losses for longer runs and is worth the extra cost.

I have a 2hp CT DC and find it does a good job plumbed up to quite a few units with gate valves to isolate what is not being used. Also avoid 90 deg bends - use 2 x 45 instead.

cheers

[Zed]

some nice work there wongo - i often wonder if "going straight up" vertically for long distances affect the ability to suck. Ie does gravity fight against you markedly ? I've seen countless photos and such but i still always wonder. in my head when design the dream workshop I always have the piping at hip or chest level (ie around about the height that the dust port outlets exit the machines!

why didnt you pain the walls white beofer you started doing stuff ?????? the reflections woulda given you some "free" light

cheers

[zenwood]

... I used 150mm PVC instead of 100mm on the basis that the cross sectional area is proportional to the square of the radius and hence is 2.25 times bigger...
I'm wondering how big is too big for these PVC pipes. As the cross-sectional area goes up the air speed in the pipe goes down (proportional to the square of the radius). For 100mm and 150mm pipes and a DC capacity of 34 cu m/min (1200 cu ft/min, fixed), I get airspeeds of 1082 and 481 m/min, respectively. The effect of the lower air speed would be that heavier particles would drop out of the flow and begin to clog the pipe (for horizontal runs). (BTW does the cost go up as the square of the radius?)

Conversely, as the diameter of the pipe goes up, the capacity of the DC system would increase a bit because of the lower drag, so the DC capacity in this example would be slightly highter than 34 cu m/min for the bigger radius.

fletty: I'd be interested in your process because I'm thinking of setting up something very similar: a 100mm pipe going along the roofline of the shed at 2.7 m height.

[dai sensei]

I'm wondering how big is too big for these PVC pipes.

If you got to Bill Pentz's site http://billpentz.com/woodworking/cyclone/DC4Dummies.cfm#CFMRequirementsTable, he recommends at least 800cfm air flow and 4000fpm velocity. You can use his static pressure calculation spreadsheet to determine both the flow and velocity of your own set-up. By adjusting the duct diameters you can then determine which ducting size is the most effecient.

If you have a length of 6" duct in line of 4" duct, ie 4" on either side, the particles will settle in the larger duct reducing its inside diameter to effectively 4".

Hope this helps.

[Dr Dee]

I'm wondering how big is too big for these PVC pipes. As the cross-sectional area goes up the air speed in the pipe goes down (proportional to the square of the radius). For 100mm and 150mm pipes and a DC capacity of 34 cu m/min (1200 cu ft/min, fixed), I get airspeeds of 1082 and 481 m/min, respectively. The effect of the lower air speed would be that heavier particles would drop out of the flow and begin to clog the pipe (for horizontal runs). (BTW does the cost go up as the square of the radius?)

Conversely, as the diameter of the pipe goes up, the capacity of the DC system would increase a bit because of the lower drag, so the DC capacity in this example would be slightly highter than 34 cu m/min for the bigger radius.

fletty: I'd be interested in your process because I'm thinking of setting up something very similar: a 100mm pipe going along the roofline of the shed at 2.7 m height.

Zenwood - You are right about the potential for drop out of heavier particles with the larger diameter pipe. This why I have gates on all the sections. If I have too many open nearer the DC then the velocity in the large pipe which is further upstream is too low and things can clog. I find that after using the system for I while I can tell by the ammount of swirling visible in the plastic DC bag and the suck at the outlet for the jointer and thicknesser what is open. When I close all the gates near to the DC the stuff at the bottom of the vertical section gets sucked up no problem.

I did a build with 100mm (no glue) first and found that the flow volume over the long overhead and vertical section was too low because of the resistance. Replaced it with 150mm and it works fine with the 15" thicknesser taking a 3mm cut off an 8" pine board. That is good for me.

The cost does increase from memory 6m lengths of 150mm cost me ~$60. The bends etc are much more expensive than 100mm but it was worth it to solve the problem and still keep my shop layout how I want it.

cheers

[Harry72]

Mate can you tell where you got the 150 for $60? Its usualy $100-120mark
I found with my system I keep the last port in line open(has no gate)it feeds off the lower cab of my Tsaw, never have any dust build up... from Tsaw-dusty by pipe is about 12-13m, 9 of it being 150mm dia also has 5 gates/drops along the way all is at roof height. My dusty is 3hp 2000cfm unit.

[fletty]

Sorry about the delay in replying but Fathers' Day got in the road. I spent a large part of today waiting to my open my gift of A LN low angle block plane that my daughters (didn't know they had ...) bought for me.
My DC is a JET 'Dust Dog' which looks like an exotic garbage bin lid with motor, impeller, guards and a filter cannister hanging off 1 side. According to the catledog it is rated at 1hp, 650cfm (@4"), static pressure 7.8" (H2O) and 7445fpm velocity (@4").
From the DC, I have a vertical riser of ribbed flexible to 2.6metre height and then a horizontal run of 4metres with 3x 3 metre long vertical drops of flexible, 1 fixed to the table saw and the other 2 connected variously to other machines in use at the time. All lines have gates so that only the line in use need be open.
Even though the unit is rated fairly low, it has sufficient grunt to adequately remove all of the swarf, shavings and sawdust from my 15' thicknesser even on deep cuts, and made a fair attempt at sucking up the short end of my now 230mm rule that was run through the table saw.
Fletty
PS I must buy a digital camera

[Skew ChiDAMN!!]

Sorry about the delay in replying but Fathers' Day got in the road. I spent a large part of today waiting to my open my gift of A LN low angle block plane that my daughters (didn't know they had ...) bought for me.

Makes the wait worth it, eh? :)

Thanks for the specs, they definitely ease my mind. If my runs won't work at ceiling height it won't be 'cos the DC can't handle 'em.

[Wongo]

I fixed an obvious mistake. The first picture shows dust going to the jointer in stead of going into the wall. :)

[zenwood]

That's good thinking 99.