Thread: which way is better?

I always recon it's better to connect individual as DIRECT to a trunk line as possible that way when a machine is moved this does not affect other machines.
Remember the blast gate should be as close as possible to the trunk line.

In your case it will make no difference because the size of the ports on those machines are the primary bottle necks and WAAAAAY to small to affect which way around things are done.
Even running machine simultaneously will not be able to take advantage of the 150+ mm ducting

63 mm duct can at most pull 120 cfm
80 mm duct ~200 CFM
100 mm duct pulls ~400
So all up about 920 cfm

Provided the impeller is up for it 150 mm ducting should pull 1350 cfm, 200 mm ducting should be closer to 1800 cfm

Originally Posted by BobL

I always recon it's better to connect individual as DIRECT to a trunk line as possible that way when a machine is moved this does not affect other machines.
Remember the blast gate should be as close as possible to the trunk line.

In your case it will make no difference because the size of the ports on those machines are the primary bottle necks and WAAAAAY to small to affect which way around things are done.
Even running machine simultaneously will not be able to take advantage of the 150+ mm ducting

63 mm duct can at most pull 120 cfm
80 mm duct ~200 CFM
100 mm duct pulls ~400
So all up about 920 cfm

Provided the impeller is up for it 150 mm ducting should pull 1350 cfm, 200 mm ducting should be closer to 1800 cfm

Thanks BobL. once my ducting are installed I will upload the photos. I think I will go with proposal 2. the main reason I will use 150 for most of the machine is to reduce the side wall effect as much as possible.

Yes these ports are very small especially the mortiser, thats why there will be no blast gate for them. when I turn my sander on (biggest air user) I dont think these little ports will have any meaningful impact on the flow if they are closed or not.

By the way I have swapped the phase on my extactor, previously it was having trouble sucking say a solid wood cut off say 1 cm3 off the floor at the end of the 100mm flexy, now I have to be careful with whats in the way otherwise it get sucked into the duct, the otherday I was doing a bit of cleaning and my stanley knife nearly got sucked in....

Originally Posted by Albert

Thanks BobL. once my ducting are installed I will upload the photos. I think I will go with proposal 2. the main reason I will use 150 for most of the machine is to reduce the side wall effect as much as possible.

Sure, but that effect is irrelevant because your inlet ports are so small. You could have run 100 mm pie all the way and have more or less the same flow.

Yes these ports are very small especially the mortiser, thats why there will be no blast gate for them. when I turn my sander on (biggest air user) I dont think these little ports will have any meaningful impact on the flow if they are closed or not.

That is not a very good reason to keep them so small. To maximise fine dust collection at the source the air collection point should be as large as possible and that means opening up the machine ports or running extra open ports as close as possible to the dust making source, not over on another machine. In addition blast gates are useful to direct greater flow from specific tools while they are in use.

By the way I have swapped the phase on my extactor, previously it was having trouble sucking say a solid wood cut off say 1 cm3 off the floor at the end of the 100mm flexy, now I have to be careful with whats in the way otherwise it get sucked into the duct, the otherday I was doing a bit of cleaning and my stanley knife nearly got sucked in....

Good point, same thing happened at work in a chemistry lab, everything metal in the lab was turning green (including a silver neck chain I used to wear) from the hydrochloric acid fumes so we got the sparky back and sure enough, phase wrong way around !

Hi, I am mystified by "phase wrong way around".
Are you talking about air flow or electrical current or what??
Cheers Barry

Originally Posted by mannum3

Hi, I am mystified by "phase wrong way around".
Are you talking about air flow or electrical current or what??
Cheers Barry

In a 3 phase motor there are 3 "Actives" or 3 phases. It doesn't matter which active wire is connected to which of the active terminals on a 3 phase motor, the motor will still work but it may be spinning the wrong way so to correct that two of the actives or phases are swapped over. This is standard procedure even for sparkies.

All OK, I can not imagine how it would suck at all running backwards.
Cheers Barry

Originally Posted by mannum3

All OK, I can not imagine how it would suck at all running backwards.
Cheers Barry

An impeller type fan creates a positive pressure around the outside of the inside of the impeller irrespective of the direction it travels. If it is travelling the right way then the blade curvature can capture more air and the air exits align better with the flow direction and less turbulence is created that when it running the wrong way but it can still deliver around 20% of the air flow of the forward direction.

Work in progress photos

too many ductings can't fit them all in photo so only taken photo for some of them

very difficult to install the ducting on my own. Didn't want to ask my wife to help, she will notice I have bought more stuff!

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work in progress.

The flex for the mortiser looks a bit long but that will shorten as the machine head moves side ways. it is at its extreme right position.



Not really a desirable layout for the dual saw second duct as its very close to the mortiser and how the flow have to bend 90 degrees twice with a branch in a short distance.... the original intention was to have this branch at the ceiling level.... I will change it tonight.

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I extended the main trunk using some spiral duct I had, had to make the lip on the spiral to make it work with my modular ducting, what a mission to carry out the ducting work if you doing it yourself without a 2nd person!

IMG_3580.jpgIMG_3574.jpg

Looks really nice (and expensive?)

Originally Posted by BobL

Looks really nice (and expensive?)

thanks BobL. It will look even better when it's all finished.

Have just tried briefly on reconnecting that dual saw duct - didn't work. It will stay as is. Have one more machine need to hook up to, the bandsaw. It will be 125mm duct. All up the stage 2 (mortiser, dual saw and band saw) costed about $2000, stage 1( combination machine, sander and the main ducts) was about $2000 as well

Originally Posted by Albert

thanks BobL. It will look even better when it's all finished.

Have just tried briefly on reconnecting that dual saw duct - didn't work. It will stay as is. Have one more machine need to hook up to, the bandsaw. It will be 125mm duct. All up the stage 2 (mortiser, dual saw and band saw) costed about $2000, stage 1( combination machine, sander and the main ducts) was about $2000 as well

I was about to ask about pvc vs metal ducting in a new thread as i need to get mine set up...metal sounds prohibitive for a temporary install.

Originally Posted by Albert

thanks BobL. It will look even better when it's all finished.

Have just tried briefly on reconnecting that dual saw duct - didn't work. It will stay as is. Have one more machine need to hook up to, the bandsaw. It will be 125mm duct. All up the stage 2 (mortiser, dual saw and band saw) costed about $2000, stage 1( combination machine, sander and the main ducts) was about $2000 as well

So $4000 on ducting?

Was there a specific reason why you didn't use PVC?

Originally Posted by Austin_Turner

I was about to ask about pvc vs metal ducting in a new thread as i need to get mine set up...metal sounds prohibitive for a temporary install.

well there are guys out there does cheaper metal ducting, 2 weeks after I've done my stage 1 ducting I needed a transition made, found this sheet metal place where they manufacture similar stuff to the JKF and cost between 1/2 -1/3 of the price I've paid, but the product they make is spiral duct, not as fancy as the smooth metal duct I have, for short distance I dont think the spiral/smooth makes any differences but anyhow the money is spent.