Fletty's new shed WIP ....or is it a retrospective??

I don't know where to start with this and I can't remember how many times I have sat down to write this post during the last month so with your permission I will just wade in.

I have long railed against rudeness and repeatedly emphasised how easy it is to offend on the internet including these Forums, primarily because for a long time we have lost the art of writing.

To my shame I am guilty of that very thing here in this thread. It doesn't matter whether we are right or whether we are wrong, there is still a polite way to express an opinion.

I did not intend offense, but I know in my bones it was there. It is a little like the quiet you experience when a joke falls flat or you pass a particularly offensive aroma in polite company.

I did the unforgiveable so I hope Fletty and RW Build can find it in their hearts to forgive.

Alan and Ray: My apologies to you both.

Regards
Paul

Hi Paul,
just got home, PM sent
fletty

Well, Fletty is every bit the "gentleman woodworker," which I don't have to tell those of you who have met him, and he assures me I have anguished unnecessarily.

I am grateful for that and I appreciate his magnanimity. From my point of view it has been a wake up call in how I approach posting. There is no mileage in posturing. It is not generally appreciated and runs a real risk of stifling debate: Not only that, if you stick your head up far enough some clown will chop it off.

Thank you to anybody reading this and your indulgence. You must have wondered what was going on. I don't really wish to go over past history in the thread as I still don't believe it reflects well on me. If you choose to wade through again, I recommend, as always, sit down with a good supply of your favourite brew.

Apart from Alan's reply, it went awfully damned quiet again. I hope normal banter will resume, because I am enjoying this thread. It has moved along rapidly and covered diverse topics, all loosely associated with the build.

Regards
Paul

I totally missed whatever happened

Good thing this place is full of top blokes including yourself Paul

Dave TTC
Turning Wood Into Art

Paul, no offence was ever taken, you don't have to lose any sleep over it.

went over my head - at about 30 thou feet

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Originally Posted by fletty

Although I know that I could throw time and money at it and do better, it will already be very much better than what it replaces. The runs are halved in length, 100mm flexi will be reduced from an average per run of 3 metres to less than 1 metre of vertical drops only AND because switching is now more accessible ....I will actually turn it on much more often!

fletty

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Hi fletty

It must be the different hemisphere, but I'm having trouble getting my head around this.

If your ducting is in the ceiling, and the vertical drops are "less than 1 metre", my poor brain -- I feel a bit like Winnie the Pooh -- calculates that the drops end well above (perhaps as much as 2 metres) a typical machine's dust port.


Time for some more photos?

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Originally Posted by ian

Hi fletty

It must be the different hemisphere, but I'm having trouble getting my head around this.

If your ducting is in the ceiling, and the vertical drops are "less than 1 metre", my poor brain -- I feel a bit like Winnie the Pooh -- calculates that the drops end well above (perhaps as much as 2 metres) a typical machine's dust port.


Time for some more photos?

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G'day Ian,
Mostly poor words on my part I'm afraid :B and I will post some pics when I get it to a stage that makes more visible sense. Basically however, I am running a single 150mm diam PVC backbone at about 2000 high in the 'low' shed and a boom mounted 150mm diam, rigid, swinging duct at a similar height in the 'high' shed, My 'prep' machinery (thicknesses, jointer, drum sander) are all castor mounted and being modified to have a 150mm outlet on the top. In the near future, I will wheel them into place, lock the castors, connect to the overhead boom duct ....and Bob's your Uncle!
In my prior set up, I had some long 'drops' (climbs?) of 100mm flex and my new anemometer was showing that this was responsible for a lot, possibly most, of my flow loss. Changing vertical runs from 100mm flex to 150mm rigid with minimal or no flex, SEEMS to have greatly reduced my losses but I'm not counting my chickens until I actually finish the machine mods and get it all into place.
I am still missing some key bits, especially for the 150mm machine outlets, and this is preventing me from fixing everything in place and sealing the whole system.
I have discovered that conflicting advice and complicated sourcing means that I want to finish it all and measure it before claiming any sought of success :C.
Just as one example, to do what I wanted to, I have so far had to source ducting and fittings from Carbatec, Hare and Forbes, Rockler, Reece Plumbing and (soon) ClearvueOz!
Until/unless I replace/modify my 2HP generic DC, I will still have a 125mm diam choke point at the immediate entry to the impellor and the same from the impellor to the filter and this must limit the effectiveness of everything I am doing beyond that point.
i have a self imposed deadline on the March 13 GTG to have it up, running .....and measured?
fletty

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Originally Posted by fletty

I thought I'd go for another milestone day ....after mowing the back paddock with the Victa :innocent:?
l started the rebuild of the dust collector system and bought my first piece of 150mm PVC pipe work!
Now I'm a reasonably intelligent man. I know that 150mm is 1.5 times bigger than 100 mm and that the area of a circle of diameter 150mm is 2.25 times the area of a circle of 100mm diameter BUT, when you actually see it.....

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If you are excited about this then you will be even more excited to know that 100mm ducting typically carries a maximum of ~425CFM while 150 mm caries about 3x more at the same pressure.

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My problem is that the inlet to the impeller on the DC is 125 mm and that this will remain my choke point until I go the 'upgraded 2hp generic DC route' :rolleyes: or buy a larger DC!

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The 125mm is limited to ~700 cfm on most DC systems.

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I have done some comparative flow loss tests and the worst offender, length for length, is, (not surprisingly)100 mm flexi. Surprisingly however, 125mm flexi is on a par with 100mm rigid PVC pipe. I haven't yet converted my machines to 150mm outlets but lm in deep withdrawal from woodwork and have even just been given a WW1 red poppy to "creatively display"?
To get back into woodwork, I'm going to create a 150mm backbone, use the absolute minimum amount of 100 mm flexi to connect the machines but make it upgradable to 150 mm when I upgrade the machine outlets. I'm planning on using 100mm flexi ONLY on vertical drops or where needed for alignment. NO horizontal runs and NO 90 deg bends.
I was quite intrigued to also measure that "100mm flexies ain't 100mm flexies" and there was a lot of variability in the test results. That beautiful, clear, VERY flexible flexi sold by Rockler with their dust right system performed the best and I THINK that is so because one of its features is that it automatically 'retracts' to the length needed when under vacuum and therefore presents a much smoother inner surface to the airflow?

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By "dust right system" do you mean those wall mounted single bag units?

Before I comment on this It would be useful to know how he comparative measurements were performed.

BTW, one way to further minimise the amount of flexy connection to a ducting system is to use ducting attached to machinery so that it looks like a snorkel i.e. comes up from low down extraction ports to about 1.8 m high (i.e. machine can still be moved around) then the machine can be parked right under a ducting port and a very short amount of flexy can be used.

Hi Bob,

"If you are excited about this then you will be even more excited to know that 100mm ducting typically carries a maximum of ~425CFM while 150 mm caries about 3x more at the same pressure."

:)

"The 125mm is limited to ~700 cfm on most DC systems."

:rolleyes:



"By "dust right system" do you mean those wall mounted single bag units?"

No, it is their quick connect 100mm Flexi hose system BUT the 100 mm flexi is VERY flexible, clear and expands up to 7 times its length with no perceivable diameter change. When under vacuum it 'retracts' to the minimum distance between its ends so much so, that the inner surface is quite smooth. VERY corny link added .... Dust Right Expandable Hose Review | Stumpy Nubs - YouTube
My 'new' setup will have a few 2 X 100 mm parallel Flexi applications including your 'snorkel' comment below.

"Before I comment on this It would be useful to know how he comparative measurements were performed"

Digital temperature corrected anemometer with input actual area for volume measurement tested as an individual entity and then with upstream and downstream entities in series to check for transmitted disturbance.

"BTW, one way to further minimise the amount of flexy connection to a ducting system is to use ducting attached to machinery so that it looks like a snorkel i.e. comes up from low down extraction ports to about 1.8 m high (i.e. machine can still be moved around) then the machine can be parked right under a ducting port and a very short amount of flexy can be used."

Exactly what I am doing on the jointer but somewhat more sophisticated :wink: on the drum sander and thicknesser. These 3, plus probably the modified bandsaw, will all have a single 150mm diam vertical-facing spigot at 1500mm height to suit the boom mounted duct.

fletty

A bit of progress today and the dust collector has been fired up in anger for the first time in weeks! I was hoping to have a system with the lowest denominator being the 125mm diameter choke point at the entry to the impeller BUT, to get me back into making shavings sooner, I'm going to have to continue for a while with some 1 X 100mm diam elements rather than the planned 150mm diam or 2 X 100mm.
The boom mounted duct...

Attachment 371782

.... for example, SHOULD be served by 2 X 100 mm diam flexies .... but a 125mm means that l can make stuff NOW :)!
l am still waiting for the 2 X 100 adaptors to use as line elements and to modify the machine outlets ...... but hey, what would I do next month if I already hand them?

fletty

Looking good Alan:2tsup:

Regards

Keith

Top idea with swing arm :2tsup:

Thanks for video link where can I get it here?

125 at the dusty am I understanding that right?

If so why don't we/you make a new resized to what you wish it to be? A bit of sheet metal work is all it takes. Happy to help.

Top idea with swing arm :2tsup:

Thanks for video link where can I get it here?

I bought mine directly from Rockler a few years ago. Lovely gear!

125 at the dusty am I understanding that right?

If so why don't we/you make a new resized to what you wish it to be? A bit of sheet metal work is all it takes. Happy to help

Not quite that easy. The entry to the impeller housing is 125mm diam plus a token flare, but impeller efficiency may be significantly reduced if the entry diameter intrudes too much into the involute and the blades then trap much less air. I've heard stories of 12", 13" and even 14" impellers being used on these generic DCs so a possible answer would be to see IF a larger impeller will fit and find one and then open up the entry hole BUT that still leaves a 125mm flexi duct after the impeller and fixing that is a much bigger issue.

Quote:

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Originally Posted by fletty

A bit of progress today and the dust collector has been fired up in anger for the first time in weeks! I was hoping to have a system with the lowest denominator being the 125mm diameter choke point at the entry to the impeller BUT, to get me back into making shavings sooner, I'm going to have to continue for a while with some 1 X 100mm diam elements rather than the planned 150mm diam or 2 X 100mm.
The boom mounted duct...

.... for example, SHOULD be served by 2 X 100 mm diam flexies .... but a 125mm means that l can make stuff NOW :)!
l am still waiting for the 2 X 100 adaptors to use as line elements and to modify the machine outlets ...... but hey, what would I do next month if I already hand them?
fletty

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It sounds like you are still working on duct area ratios which is incorrect - it takes 3 x100 mm ducts to carry the same amount of air as 1 x 150 mm duct at most DC pressures.

Quote:

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Digital temperature corrected anemometer with input actual area for volume measurement tested as an individual entity and then with upstream and downstream entities in series to check for transmitted disturbance.

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It would be useful if you quoted some actual flow numbers but what I also wanted to know were things like
What sort of anemometer was it? i.e. propellor based or hot wire anemometer?
What sort of air speeds were you measuring and what was the maximum air speed it could measure?
These questions are important because most hot wire anemometers can only measure up to 30m/s and in a 100 mm duct the air speeds might be greater than this.

Did you
- use a smooth wall test duct at least 1m long with a test port in the side of the test duct at the 500 mm into which the anemometer was inserted
- measure the air speed as function of radius across the test duct
- determine the air flow at each elemental radius
- integrate the air flow at each radial annulus.
If this is not done it will not give an accurate measurement of the flow.
Placing the anemometer in the end and in the middle of the duct and multiplying the resultant air speed by the area of the duct will give results that are incorrect by as much as 40% which is far greater than would be observed between different types of ducting.

Checking for radial variations of air speed is also important to detect turbulence.

Regarding the rockler flexy - I'm struggling to see how it can maintain a straight smooth bore once it is stretched even a small amount. Unless the material between the wire rings actually stretches it must fold creating wrinkles in the wall. If it stretches it must constrict slightly between the wire rings. A close up side on photo of it slightly stretched and fully stretched would be interesting to see.