Dust Collector grounding

[tim walker]

I have a ClearVue cyclone and use 6' PVC piping for my ductwork (yeah I know). We live in the Hill Country of Texas and in the summers especially have relatively low humidity (7" of rain so far since Jan 1 on top of the whopping 11" from 2022), so yeah it is really dry. I saw humidity down to 19% last week. My shop is in a 900 sf garage with one single insulated garage door. The entire shop is insulated on all 4 walls and roof with spray foam and is climate controlled to 72F in summer. There is a 6" concrete slab.

I know I need to ground my piping as evidenced by the collected fine dust on the PVC piping, but I am not sure how to go about it. I thought some of you guys have had this issue and /or know how to rectify it. I jump from my PVS pipes to Rockler (or others) expanding 4" piping that has a wire core. Dust collection is set up to the following: Table saw, router, drum sander, jointer, planer, band saw, and partially to drill press and miter saw. You can see a partial layout in the photos and also a close up of how static electricity is causing the dust to adhere to the outside of the PVC.

Open to all suggestions. 505975505976

[Michael Burnside]

For my CNC I just got bare copper wire and tightly wrapped it around approximately 1 revolution per 2 feet. Then just ground both sides to earth ground. One on CNC and one on my dust collector motor mount.

Basically you just need something with a lower potential to dissipate any charge that accumulates.

[Andrew More]

I know I need to ground my piping as evidenced by the collected fine dust on the PVC piping, but I am not sure how to go about it.

Why do you believe this? It's not a fire hazard, at the scale your shop, and most small shops work at. Further it's not really possible to ground an insulator, like PVC. Unless you're getting regular shocks and find it annoying, I'd leave it alone, and find a more productive use of my time.

https://www.youtube.com/watch?v=C1RWjLP5QF0&t=33s

[Matthew Hills]

Has anyone tried anti-static coatings on PVC to see if that helps reduce the charge buildup?
(first one that came up looked interesting, but pretty expensive)

Matt

[George Yetka]

Why do you believe this? It's not a fire hazard, at the scale your shop, and most small shops work at. Further it's not really possible to ground an insulator, like PVC. Unless you're getting regular shocks and find it annoying, I'd leave it alone, and find a more productive use of my time.

https://www.youtube.com/watch?v=C1RWjLP5QF0&t=33s

I would say if there were no cnc I could agree with this. But the cnc is sensitive and the static can cause issues. Something like Michael mentioned would more than likely take care of it. You can tie the copper to the metal in the flex if you expose it on either end. My planer was my biggest offender of shocks, which was annoying but didnt hurt anything. I have rf issues on my cnc, luckily it just causes my screen to black out 5 seconds off 1 second on when my spindle/vfd are running.

[Gordon Stump]

I do this: Wrap wire around aluminum rivet and rivet to pipe every few feet.

[Jim Becker]

I would say if there were no cnc I could agree with this. But the cnc is sensitive and the static can cause issues. Something like Michael mentioned would more than likely take care of it. You can tie the copper to the metal in the flex if you expose it on either end. My planer was my biggest offender of shocks, which was annoying but didnt hurt anything. I have rf issues on my cnc, luckily it just causes my screen to black out 5 seconds off 1 second on when my spindle/vfd are running.
This is very true. It's not really a factor for most traditional woodworking tools, but CNC routers are a different animal and things have to be grounding properly to avoid missed steps or worse.

[Keegan Shields]

You can't effectively ground an insulator like PVC. Insulators build up static locally unlike conductive metals where the electrons can flow through the object.

That's why teachers use glass rods (an insulator) and not copper rods to demonstrate static discharges in physics class.

So, wrapping a copper wire around PVC pipe will pull the local static charge from the area around the wire, but not the whole pipe.

[George Yetka]

You can't effectively ground an insulator like PVC. Insulators build up static locally unlike conductive metals where the electrons can flow through the object.

That's why teachers use glass rods (an insulator) and not copper rods to demonstrate static discharges in physics class.

So, wrapping a copper wire around PVC pipe will pull the local static charge from the area around the wire, but not the whole pipe.

You can mitigate a lot of it. Foil tape is another solution.

https://www.supplyhouse.com/Venture-Tape-1520CW-3-Aluminum-Foil-Tape-3-x-150?utm_source=google_ad&utm_medium=Shopping_tm&utm_campaign=Shopping_TM_Returning_users&gclid=Cj0KCQjwoeemBhCfARIsADR2QCtG2dJ7mjDJ1TtYTzuI elxRGYR8LSvDxYZOTWRrwPR3O0uNsZl_Mh0aAtyoEALw_wcB

[tim walker]

Thx Andrew, good video. Not concerned about explosiveness or even shocks really, would just like for the dust buildup on the outside of the pipes to be less.

[Andrew More]

Thx Andrew, good video. Not concerned about explosiveness or even shocks really, would just like for the dust buildup on the outside of the pipes to be less.

You're welcome. If it bothers you, it bothers you. Maybe better dust filtration would be more productive? Like I said, I don't think you can "drain" the static charge on PVC, because it won't conduct the charge to the grounding wire. You can make a pretty effective filter using a box fan + furnance filter. If that bothers you, you can usually get old HVAC blowers cheap on FB market place, and build a box to hold them.

[tim walker]

I have an overhead filter system, I guess I just need to run it more.

[Bill Dufour]

I have seen pictures of a strand of Christmas tinsel sprial wound outside the plastic duct work. I assume the aluminum is grounded at one end or the other , maybe both. There is no need for metal to pierce the insulating plastic. The charge will migrate to the lowest potential even through an insulator.
Bill D.

[Bert McMahan]

Though I haven't tried it myself I'd suspect aluminum HVAC foil would help dissipate it greatly.

[Michael Burnside]

I have seen pictures of a strand of Christmas tinsel sprial wound outside the plastic duct work. I assume the aluminum is grounded at one end or the other , maybe both. There is no need for metal to pierce the insulating plastic. The charge will migrate to the lowest potential even through an insulator.
Bill D.

Spot on Bill. I was replying in the context of annoying static building up on the outside and shocking you or for CNC purposes. In those contexts, your idea and my solution work. If someone is seriously worried about a fire due to static on the inside, which the OP said he wasn't, then standard PVC really isn't even the correct solution to begin with.

[glenn bradley]

Ignoring the unfortunate phrase "grounding the duct work" all you are trying to do is provide a path to ground that the static charge will prefer over the path you don't want it to take. Like Michael mentions an insulate or non-insulated 18 gauge wire wrapped about once per foot or so from end to end will do it as long as one end is fastened to a ground. The PVC is an insulator which his why the charge stores up. As soon as the charge becomes enough to jump to the available ground it does so. The wire is readily available so the charge never builds up very far. With out the wire, you or your sensitive equipment can become the best path to ground.

[mike calabrese]

Just an FYI couple of videos
calabrese55
https://www.youtube.com/watch?v=C1RWjLP5QF0
https://www.youtube.com/watch?v=WJ8NMYlhaLQ

[Keegan Shields]

I’m not sure I follow. How do you mitigate static without covering most of the PVC in a conductor?

Again, insulators gather static charge locally on the surface and do not allow electrons to flow through the material. So you’d need to cover your PVC pipe in metal tape and ground it.

If you want a grounded pipe, use a metal one.

[George Yetka]

I’m not sure I follow. How do you mitigate static without covering most of the PVC in a conductor?

Again, insulators gather static charge locally on the surface and do not allow electrons to flow through the material. So you’d need to cover your PVC pipe in metal tape and ground it.

If you want a grounded pipe, use a metal one.

Keegan, It does work I had a section on my old system that was pvc that was hooked to a lunchbox planer. it created a lot of static and everytime I brushed it while running I got good shocks. I ran the foil tape to the spiral duct and that ended them.

https://www.thegeekpub.com/3621/grounding-a-dust-collection-system/

[Rege Sullivan]

As most of the solutions mention you need to make the outside of the pvc conductive. I'd bet a conductive paint like that used for shielding could work. Also you might lurk on a guitar building forum as those guys fight static on their pick guards. Some have experimented with conductive coatings with some success.

[Jim Becker]

As most of the solutions mention you need to make the outside of the pvc conductive. I'd bet a conductive paint like that used for shielding could work. Also you might lurk on a guitar building forum as those guys fight static on their pick guards. Some have experimented with conductive coatings with some success.
In the guitar example, it's not really about static electricity...it's about RF hum. Hence, the shielding tape or paint to help keep the "buzz" at bay. Everything has to be grounded to the same point.

[Bill Dufour]

A lightening rod works fine in non conductive air. I would guess PVC is not much better a electric insulator then dry air. A lightening rod has a cone of protection at 45 degrees out from the tip to the ground. So the pipe can be wrapped with a grounded conductor and be fully protected.<br>
BilL D.<br><br>spark gap is 75,000 volts per inch to initiate a spark, less to keep it going.&nbsp; If the path to a ground wire is slightly less insulated then that no voltage will build up, no sparking.&nbsp; Normal home wire is insulated to 400-600 volts by code.&nbsp; So 600/75,000 = 0.01" seperation.&nbsp; Any gap that small would probably be filled with sawdust and conducting current before it sparked.