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Question about a static ground for Super Dust Deputy

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Forum topic by jkm312 posted 10-13-2020 12:14 AM 659 views 2 times favorited 20 replies Add to Favorites Watch
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jkm312

54 posts in 316 days


10-13-2020 12:14 AM

I have not found this topic mentioned yet. I added an Oneida Super Dust Deputy cyclone to my single stage Jet DC 1100 to convert it to a two stage system. Used 4” pvc sewer pipe and aluminum blast gates. I’ve not had it up and operational for long. This is the 3rd redesign for the DC. The last two setups I used all ribbed dust collector hose. I put in a static ground the first time, running the wire inside of the hose. No real problems with clogs. The second time I moved the DC across the shop to get it away from the AC vents and filters. Didn’t really work as well, too far from the table saw was the main issue I didn’t like. Didn’t ground it.

I’m the proud owner of a pacemaker. A possible large static shock is not in my best interest so I’m going to ground the pvc pipe and blast gates by wrapping the wire around the pipe and securing it with screws thru the pipe every 12 + inches or so. A continous line all the way to the DC and then connect it to the blower housing for the final ground.

I’ll use spades and paddles to be able to take the Cyclone and collection drum out of the line to empty as needed.

My question concerns the cyclone and drum, 30 gallon. How much do those two need to be grounded? Both are plastic. Seems to me that is where a lot of static is possible because of the swirl of air and debris. Between the cyclone and pvc line I have a metal 5” to 4” reducer.

I’m not overly concerned about a dust explosion in a hobby shop like mine, but a static shock makes me cautious.

What is the right way to finish up? Thank you in advance for your consideration and advice


20 replies so far

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WhyMe

1322 posts in 2474 days


#1 posted 10-13-2020 12:44 AM

I have a pacemaker and have done alot of research on what can cause problems and typical static electricity shocks won’t cause a problem. I have a newer PM that’s MRI safe and I even use a mig welder with no issues.

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ibewjon

2136 posts in 3706 days


#2 posted 10-13-2020 12:49 AM

I don’t know anything about pace makers. If you don’t want a shock, you can either use a steel cyclone, or if it is still made, there was a static dissapating cyclone made from a special plastic. As for the duct, pvc is an insulator and you can not ground an insulator. I would be using steel duct. I use 26 gauge, 5” Snap Lok. I have seen various methods to remove the static from pvc pipe. I wouldn’t give a nickel for any one of them. One person says he grounded pvc by wrapping foil tape in a spiral around the pipe. I tested foil tape on steel duct. The problem is the adhesive on the tape is an insulator. I tested the connection from the tape to the duct with a Fluke 87-V meter, and the resistance was too high to be called an effective ground. Screws through the pvc can at most bleed static from that point. Wrapping bare wire around the pvc results in a similar poor ground connection. If no shock is critical to your life, don’t take a chance. Steel is about the same or cheaper than pvc in my experience. That is another reason I used it. Stay safe.

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clagwell

323 posts in 705 days


#3 posted 10-13-2020 10:07 AM

Your SDD is made from static dissipative HDPE. It can and should be grounded the same way you ground a metal body cyclone.

ibewjon is correct about the PVC. It’s an insulator and can’t be grounded.

Dust sliding along the inside surface will lose an electron to the PVC surface, picking up a positive charge and leaving a negative charge on the inner wall of the pipe. You can’t stop it from happening and you can’t remove the charge in the pipe. It can only leak away on it’s own.

A grounded wire wrapped around the pipe doesn’t discharge the inside of the pipe. Instead, it works by shielding you from the effects of that charge (“Electric Field”). It does this by pulling an equal but opposite charge from ground and effectively “cancelling out” the pipe’s charge.

There’s no need for anything conductive inside the pipe. It won’t do any thing unless you line the entire inner surface.

I agree with ibewjon’s recommendation. Use 5” snaplock. No static and it has one third the pressure loss of 4”. You’ll have much better airflow in addition to eliminating any static problems in the ducts.

For flex hose, use the kind with a wire spiral and ground that.

-- Dave, Tippecanoe County, IN --- Is there a corollary to Beranek.s Law that applies to dust collection?

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Robert

4134 posts in 2393 days


#4 posted 10-13-2020 01:47 PM

I do experience some static in my ducts, not enough to ever shock me, just make my arm hair stand up, that said I live in a fairly humid environment.

But I have gotten zapped bad enough touching an aluminum blast gate, so I grounded them.

Off topic, but next time you remodel, go with 6” ducts, your system will perform much better even with the cyclone. I have the exact same set up you have.

-- Everything is a prototype thats why its one of a kind!!

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EarlS

4076 posts in 3261 days


#5 posted 10-13-2020 02:22 PM

There are several places (Rockler, Peachtree) that sell kits with some copper wire that you can connect to your system with duct tap, metal straps, or whatever that can be used to make a circuit to dissipate the static electricity build up.

When I first got my DW-735 planer I could see the static sparks jumping from the hose to the planer outfeed table. After a couple good jolts, I spent the $$ for some wire and took the time to ground the entire DC set up. I run copper along the PVC and strap it on with metal straps every couple feet.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

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ibewjon

2136 posts in 3706 days


#6 posted 10-13-2020 02:26 PM

Robert, you have humdity in Florida? New one on me. We have it in Illinois in the summer, but winters get bone dry. Static can be a big problem here. As for 6” duct, that is too big for a 2hp. I had it and reduced to five inch all the way. A great improvement. Remember, 6” is 2 1/2 times the size of a 4” duct, and 50% larger than 5” . The small machines can not move that much air.

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fivecodys

1673 posts in 2549 days


#7 posted 10-13-2020 06:16 PM



Robert, you have humdity in Florida? New one on me. We have it in Illinois in the summer, but winters get bone dry. Static can be a big problem here. As for 6” duct, that is too big for a 2hp. I had it and reduced to five inch all the way. A great improvement. Remember, 6” is 2 1/2 times the size of a 4” duct, and 50% larger than 5” . The small machines can not move that much air.

- ibewjon

Yep. You are correct. 6” is too big.
I have the same DC1000 and the same SDD. Oneida recommends 5” duct for that blower and that’s what I did. Yes, the fittings are expensive. The ductwork wasn’t too bad.
I treated this just like a tool purchase. Buy once, cry once, and then get over it and go to work.
It’s been almost two years and I have no complaints.

https://www.lumberjocks.com/projects/388617

-- A bad day woodworking is still better than a good day working.

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AndyJ1s

471 posts in 668 days


#8 posted 10-13-2020 07:30 PM

Please note that the charge transferred from pipe to sawdust may be positive or negative, depending upon which material (PVC or cellulose) more easily gives up or accepts additional electron(s) to the other material.

-- Andy - Arlington TX

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clagwell

323 posts in 705 days


#9 posted 10-13-2020 08:19 PM


Please note that the charge transferred from pipe to sawdust may be positive or negative, depending upon which material (PVC or cellulose) more easily gives up or accepts additional electron(s) to the other material.

- AndyJ1s

The PVC will be negative. Check the charge affinities in this table.

Not that it really makes any difference.

-- Dave, Tippecanoe County, IN --- Is there a corollary to Beranek.s Law that applies to dust collection?

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ibewjon

2136 posts in 3706 days


#10 posted 10-13-2020 10:44 PM

To save money, I only bought the long radius 90’s. I purchased a spot welder from HF, and made my own Y fittings.

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jkm312

54 posts in 316 days


#11 posted 10-14-2020 12:43 AM

Why Me – I’ve only had one instance of trouble from outside sources. I walked by a truck grinding up office records from banks and lawyer offices etc. They had a diesel motor turning an electric generator powering the electric motorr powering the grinder. The magnetic field from the generator made me very light headed until I got out of range. Nuf of that!

lewjon/Robert – I live in Iowa, winter gets pretty dry and static shock can be a problem. My plan is to wrap the bare wire around a screw sticking thru the pvc pipe acting like a lightning rod and continue down the length of pipe to the blower. Try and give it’s own path back to ground as much as can be expected

clagwell – I considered metal pipe, but no readily available source here for what we needed so went the 4 inch pvc route. Next up was 6”, but too big for my equipment.

I put in the last drop today trying to clean up the mitre saw, which we all know are notoriously evil for dust collection.
I have a Bosch glide saw. I made a lager boot at the blade, ran a small hose out of the dust fitting up behind the motor, directly into a 4 ” pipe connected to a “big gulp” on top the the shroud. Collecting the debris as close to the source as you can seem to work OK today.

I’ll try to get some photos posted in the near future.

Thank you all, for your help and guidance.

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ibewjon

2136 posts in 3706 days


#12 posted 10-14-2020 12:57 AM

I know the area. Daughter graduated from Augustana. I also worked at a pipeline compressor station near you, north east of Eldridge. Home Depot, order on line, pick up in store. Menards as well. Order fittings on line.

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bluemack

2 posts in 35 days


#13 posted 10-20-2020 05:16 PM

Just joined this site after a recommendation from a buddy when I asked him about my situation. I’m a rookie woodworker and not inherently handy.

I’ve just started a project and was planing some hickory boards, and ran a vacuum hose from the planer directly into a cyclone bucket, which seemed to work great for collecting the shavings. Unfortunately when I emptied those shavings into a plastic trash bag I received a violent shock that almost knocked me on my back- burned my fingers and felt it in my heart – glad to be able to type to the forum. I don’t totally understand the comments above – if somebody could take a step back and describe a safe setup for such things I’d appreciate it. thanks

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ibewjon

2136 posts in 3706 days


#14 posted 10-20-2020 06:07 PM

Can you post some pictures of your setup for dust collection. That will help.

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clagwell

323 posts in 705 days


#15 posted 10-20-2020 06:37 PM



I ve just started a project and was planing some hickory boards, and ran a vacuum hose from the planer directly into a cyclone bucket, which seemed to work great for collecting the shavings. Unfortunately when I emptied those shavings into a plastic trash bag I received a violent shock that almost knocked me on my back- burned my fingers and felt it in my heart – glad to be able to type to the forum. I don t totally understand the comments above – if somebody could take a step back and describe a safe setup for such things I d appreciate it. thanks

- bluemack

That effect has been reported many times. What’s happening is that the dust picks up a charge rubbing against the hose/duct. The dust deputy and bucket are both insulators so that charge has nowhere to go. Wood is a conductor at static voltages/currents so when you touch the dust the entire charge is available to shock you.

The solution is grounded metal inside the bucket. People often use Aluminum tape on the bottom, continuing up the side and over. A ground wire then connects to it. As an alternative, put a bolt through the bucket for a connection to the tape to an external ground wire. Anything that gets a metallic connection from the inner dust pile to ground should work.

-- Dave, Tippecanoe County, IN --- Is there a corollary to Beranek.s Law that applies to dust collection?

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