Thread: PVC Duct and Static

Watching this thread with interest.

How about this for starters?

Pete

Originally Posted by Glenn.Visca

Ok learned ones. I have read a couple of posts on this forum that suggested static electricity build up in PVC ducting causing sparks and unwanted fires is considered b.s. based on unsound science.

The other day, I happened to be talking to a nice fell at ezyduct, who was quite chatty even when I told him his product was way too rich for my blood.

Anyway, during our chat he asked about how I was planning to deal with static build up. He evidently has has a customer who has ezyduct, but also has a section of PVC (presumably an industrial installation), and has had several fires.

Can someone explain why static is believed NOT to be a problem ?

Not this old hoary chestnut again.

Form a scientific perspective I agree with this guy.
http://home.comcast.net/~rodec/woodw.../DC_myths.html

https://home.comcast.net/~rodec/wood.../DC_myths.html

Fires are more likely to be due to smoldering embers in the dust, not the material of the ducts.

Great minds think alike.

Pete

Asked and answered ... In spades ! Thanks !

When I built my cyclone, I used Bill Pentz's site for reference, I also went with his recommendation regarding PVC pipe.
I have had a fire in my cyclone, it was not caused by static, but from cutting a billet of Dead Finish up on the bandsaw, if I remember correctly Ttit had a fire from cutting some of the same log.
I started a thread about it back then, will see if I can find it.
Here 'tis -
https://www.woodworkforums.com/showth...t=fire+cyclone

Ironwood,

I read your fire thread and also the cyclone build thread. Both made interesting reading. Thanks !

Reading the previous two posts brought to mind that a smoke source and a basic smoke detector could be a useful way of testing the fine dust capture capability of a dust extraction system.

It's not quite as straightforward as it sounds as the smoke source has to be at the source of the dust making activity with the blades etc at full speed. e.g. it's not an adequate test for a TS blade guard unless the blade is going around as the blade contributes significantly to the dispersion of duct.

Cutting a piece of hard wood with a blunt blade to generate the smoke is not really that desirable but that would be the closest valid test I can think of.

Ummm ... I don't think I am following. The smoke detector to detect smoke ? Or dust ?

Originally Posted by Glenn.Visca

Ummm ... I don't think I am following. The smoke detector to detect smoke ? Or dust ?

Smoke - as an analog of dust.

Smoke will move around like fine dust so the smoke from from a smoking saw will go where the fine dust goes. If your DC is grabbing all the fine dust it will also grab all the smoke.

So if you place the smoke detector in a certain part of the shed and generate the smoke by/at a machine the detector will tell you if your DC is grabbing all the fine dust. If not the fine dust (nmoke) will eventually make its way to the location of the detector.

If you have your DC inside a shed this will also show if your DC is capturing the fine dust - i.e. filter is working and DC not leaking.

If you decide to do this test please be careful and don't set your shed alight.

Originally Posted by Glenn.Visca

Ironwood,

I read your fire thread and also the cyclone build thread. Both made interesting reading. Thanks !

No worries .

I dont know what has happened to the photos, they seem to have disappeared .

Originally Posted by BobL

Smoke - as an analog of dust.

Smoke will move around like fine dust so the smoke from from a smoking saw will go where the fine dust goes. If your DC is grabbing all the fine dust it will also grab all the smoke.

So if you place the smoke detector in a certain part of the shed and generate the smoke by/at a machine the detector will tell you if your DC is grabbing all the fine dust. If not the fine dust (nmoke) will eventually make its way to the location of the detector.

If you have your DC inside a shed this will also show if your DC is capturing the fine dust - i.e. filter is working and DC not leaking.

If you decide to do this test please be careful and don't set your shed alight.

No plans to even attempt. I have enough jobs on my plate at the moment.

Mind you, I do have a couple of blades that are excellent at producing smoke !