PVC pipe based dust collection

[Pop]

Knowing I needed some sort of dust collection but not seeing too many other systems around here, I opted to use PVC pipe for my shop lines. I bought a 2hp double bag setup, replaced the bottom bag with a clear plastic bag and made a remote on/off switch that sets above my workbench. After reading a few other threads on other sites about using PVC being a no no becuase of static electricity buildup and discharge, I realized why my eyes would light up on occasion while using mine. Having a limited budget for operations (Which is why I used PVC to begin with), I needed to come up with a solution to eliminate the static charges.

I bought a box of stainless #8 x 5/8 phillips pan head self drilling screws and placed then on all the plastic pipe at 8" intervals. I left enough of the screw above the pipe surface so I could take and wrap general project wire around it before snugging it down. I started at a close receptacle so I could get a good ground point and wrapped the wire around each screw one turn from one end of the piping to the other. Then snugged the screws down against the pipe. The lenght of the screws made it extend into the air flow in the pipe far enough to drain off and static charge before it became dangerous. I figured the stainless would keep it from wearing down too quickly. Well... it worked! I no longer light up the shop while using it to vacuum the floor or bench tops.

 

[Gotcha6]

Sounds like ya got it licked! I was thinking of doing my DC system this year but I thought I'd just use some #14 AWG bare solid copper wire on the inside of the pipe with a pass thru hole drilled at each end behind the fitting. I'd then bond them across the fittings like you did. I felt this would pick up the static better & not create a snag point if I kept it taut against the pipe.

 

[McRabbet]

Mike,

Static charge buildup can be a disconcerting problem with PVC ductwork, but in hobby DC applications, there have not been any fires or serious injuries reported from discharges. This link from our Link Library gives some very useful information (we found it through Bill Pentz' website on Dust Collection Research (a must read!). There are several of us that have PVC-based systems -- I am starting a major upgrade to a ClearVue Cyclone and I'm installing 6" PVC ducts. Your method sounds like it will help, but the best ones I've read about use metal tape inside and outside that are jumpered at each connection so joints can be adjusted when necessary. Some folks just deal with the static at the flexible hose and ground the coil wire.

 

[Pop]

Sounds like ya got it licked! I was thinking of doing my DC system this year but I thought I'd just use some #14 AWG bare solid copper wire on the inside of the pipe with a pass thru hole drilled at each end behind the fitting. I'd then bond them across the fittings like you did. I felt this would pick up the static better & not create a snag point if I kept it taut against the pipe.

Remember all that 'stuff' flying through the pipe has grit and enough resistance to wear things down. And drilling a hole for trasnsition will also cause a leak at that particular area. Multiply that hole times the number you drill and it could cause a lot of whistling too. The tip of the ss screws I used only protrude about an eight of and inch into the stream ... just enough becuase of how close I put them, to attract and drain off any static charge thats developing.

 

[gdoebs]

I'm installing my ClearVue and PVC duct now. I'm using the foil tape method. After cutting the pipe to length I drill two holes at the ends. Then I put the tape on the inside and outside, then put a 1" bolt with washers and a nut to capture the wire. I'll wire nut the ends together when I get them all installed. I'll have picts too, once I find that stupid cable!

 

[meika123]

Like so many others I am using PVC ductwork also. I have been using a homemade DC with 4" piping. Now I am setting up my cyclone, and switching to all 6" PVC. I have never experienced a shock in the years I have been using PVC. Not saying it doesn't exist, just that I haven't had any.
Must be my "Electric Personality". I didn't really say that-did I? :gar-Bi

 

[Alan in Little Washington]

Pop,

Please read Rod Cole's article at Rob's link about the static dangers MYTH. This myth pops up every few months on various WW forums and keeps getting promulgated, like many urban legends, by the uninformed.

I have had PVC ducting on a 3 hp cyclone for almost 10 years. Static has never been an issue- never any uncomfortable zaps, and certainly, absolutely NO explosions or fires, HONESTLY, REALLY, TRULY!!!!! The physics are just not right for that to happen in a shop DC. Moreover, my cyclone works in a push-through mode- meaning everything hits the steel fan impeller before going into the cyclone- though it is enclosed and I can't see what is going on so can not absolutely say there has been sparks from metal pieces hitting the impeller, I am sure it has occurred, yet I still have never had an explosion, nor fire, etc.- again, because the physics (mainly large enough spark and extreme concentrations of dust in a stagnant air mass) are not there to make it happen.

So, while grounding can't hurt, unless it impacts your the airflow, grounding wires, screws, metal tape, etc. etc. are just not needed and a waste of time and money in a home DC system.

PVC- if you haven't purchased your PVC pipe yet and haven't noticed the posts here, the PVC you should get goes by a number of different names: S&D* (sewer and drain), "solid perf," and has the following technical description: ASTM 2729 . *S&D comes in ASTM 2729 and the slightly heavier and more expensive ASTM 3034. Though the price of this pipe is only slightly less than the much heavier Sched 40, 2729 fittings are much cheaper. 2729 and 3034 have the same OD and use the same fittings, but Sched 40 does not. There are threads here about sources of 2729.

Oh, another thing- do not glue your pvc and fittings together!!! When (NOT IF) you reconfigure, it is much easier to do if the parts are friction fit. If you want a little better seal, use a small bead of silicone (NOT latex) caulk on the outside of joints, AFTER everything is put together (remember everything is under suction so will pull the caulk tight when in use.) You can easily rub off the silicone with just a finger, and easily take everything apart to reconfigure your piping layout.

 

[Pop]

I'm really glad to hear that there are lots of us that use pvc for the dc systems in our shops. Not being a big shop, I wasn't too concerned over the probablility of dust explosions but more the nuisance of the zap I would get when using my system to clean up the shop with the floor attachment. I would get a zap when I was using it to suck up all the sanding dust when I would connect it to my sanders too. The ground wire eliminated that totally.

The tape method... are you using the metal duct tape we used when we would build plenums and ductwork for home heating and AC work? I never even thought of that. Hmmmmmmmm. I still have a couple more take offs to do for some of the portable stuff in the shop and thats a viable method for them. I may try that for them.....

I figured this group would be a good base for more information. Cool...

 

[Bas]

I realize I'm drifting off topic here, but I have some minor problems with static electricity. This has nothing to do with my DC PVC piping, it's the equipment itself that builds up a static charge. Whenever I touch the cast iron of my table saw, jointer or band saw (even if they haven't run for 24h), I sometimes get a (very) minor zap. Only happens in winter when the air is dry (basement shop). Needless to say, the equipment is plugged into grounded outlets.

I suppose I could run a copper wire to each machine, but I'm not sure what to ground it to, and how to avoid a mess of wires through the shop.

Amusing side story: In-laws built a house several years ago. Recent inspection showed the power panel was grounded to the water pipe under the house. Unfortunately, the water pipe was PVC...........:eusa_doh::eusa_doh:

 

[Pop]

You gotta remember the static charge thats built up is looking for a place to discharge. The equipment in this case is the ground its looking for, just like the static charge you build up when you walk across a carpet and go to turn on a light swithc, or the charge you've built up that winds up going thru your spouses lips during a kiss (unless you're a newlywed then they say it's just the electric attraction you have for each other). At our (of course I'm speaking for myself) age the charge is more of a pfttt... no fault of ourown of course. The problem isn't with your equipment, it's obviously grounded fiarly weel because it attracting the charge. You have to consider the humidity you mentioned, what your wearing (get rid of the wool underwear) and what the floor of your shop is covered with. Vinyl flooring , believe it or not, will build a charge as you walk across it. Lots of sawdust buildup in a dry climate will do the same.

 

[Pop]

I have to apologize now for all the typos you'll see in some of my posts and replies. After using my hands for a long period during the day, they get a mind of their own when the arthritis takes hold and starts them straying from their designated targets. I'm learning to edit/pre-read any thing I type now but after years of working on teletypes and computers, my mind still thinks my hands are following what I'm thinking. Another reason I don't do as much scroll saw cutting as I used to... I like have 10 fingers.:gar-Bi

 

[Jim Murphy]

I suppose I could run a copper wire to each machine, but I'm not sure what to ground it to, and how to avoid a mess of wires through the shop.

Obviously, you are unaware of the multiple benefits that attach to those who don a fedora crafted from metal pots with aluminum foil bunny ears. When the nasty static charges build up, you merely tip your head (and your bunny ears) toward a likely recipient, such as your saw table, and ZAP, the charge becomes a discharge with no attendant pain to the suitably festooned.

Now how long before a picture of someone wearing such a chapeau is posted?

Aw, shucks. I'll do it.

 

[Pop]

Jim ... that's Great! I can picture my wife's response if she walked into the shop and I had one of her mixing bowls on my head...equipped with rabbit ears. No wait............. I know what her response after 40 years of marriage would be... she'd just shrug her shoulders and come in the house.:rotflm:

 

[Cliff]

Bas, your amusing side-story just made my day. I can see it now:

"I was just doin' it like they said on tha internets. Cold water pipes makes good grounds, they said..."

Hey... it's better than grounding to a natural gas line.:kamahlitu

 

[RandyJ]

Pop, since you're new here, you may not know the gentleman in the "Fedora". That's our very own Mr. "Electric Personality", Sapwood. When things get boring, we can always count on him to "liven" things up:rolf:

 

[Bas]

Jim, thanks! I knew I should have asked the experts here a long time ago! One question: Should I use the left ear for a left-tilting table saw, or will both work?

 

[McRabbet]

I realize I'm drifting off topic here <snip> it's the equipment itself that builds up a static charge. Whenever I touch the cast iron of my table saw, jointer or band saw (even if they haven't run for 24h), I sometimes get a (very) minor zap. Only happens in winter when the air is dry (basement shop). Needless to say, the equipment is plugged into grounded outlets. <snip>

Bas, unfortunately, you've got it wrong here! Your equipment doesn't build up a static charge -- it is YOU that is building up the static charge. Grounded metal things are generally very good conductors of electricity and any "buildup" they may have is rapidly dissipated to equipment ground. On the other hand, the human body -- including those of western european origin -- is a poor conductor and static electricity can build up on the surface of the body to very high potential during those cool, low humidity months -- might even be a "hair raising experience" (BTDT). When you get zapped, you are transferring your excess HV static charge (aka "High Bas Potential") from you to those nice shiny [strike]toys[/strike] tools in your shop...

Now if you are getting a 120V or 230V shock from a machine source, your wiring needs to be checked.

 

[Bas]

Rob - I don't care that the other folks on the advisory panel say, sometimes you make a lot of sense So basically I'm shocking, not shocked. No surprises there :rolf: It's definitely me, not the wiring, since I shock even when the tool is unplugged.

There is obviously a design flaw with the body. Who do I contact for support, is this taken over by the WMH tool group as well?

One solution is to simply ground myself to the table saw via a flexible piece of wire. Then the only thing I have to worry about is accidentally strangling myself as I move around in the shop:sign5:


(BTW, Electricity is always such complicated upside down stuff - current "flows" from high to low voltage but the electrons move from low to high. Same with lightning, the current flows from the earth to sky, not the other way around. It would have been a lot simpler if those early physicists had switched high and low....)

 

[Alan in Little Washington]

I realize I'm drifting off topic here, but I have some minor problems with static electricity. This has nothing to do with my DC PVC piping, it's the equipment itself that builds up a static charge. Whenever I touch the cast iron of my table saw, jointer or band saw (even if they haven't run for 24h), I sometimes get a (very) minor zap. Only happens in winter when the air is dry (basement shop). Needless to say, the equipment is plugged into grounded outlets.

I suppose I could run a copper wire to each machine, but I'm not sure what to ground it to, and how to avoid a mess of wires through the shop.

Amusing side story: In-laws built a house several years ago. Recent inspection showed the power panel was grounded to the water pipe under the house. Unfortunately, the water pipe was PVC...........:eusa_doh::eusa_doh:

Bas- What Rob said- it isn't "the equipment itself that builds up a static charge" it is YOU- you get the zap when you touch the already grounded machine.

You are just an electric sort of guy! :rotflm: :rotflm: :rotflm:

 

[gdoebs]

The tape method... are you using the metal duct tape we used when we would build plenums and ductwork for home heating and AC work? I never even thought of that. Hmmmmmmmm.

Yepper, that's the stuff I'm using. I got a 50 yd roll at HD for $8 I think. Maybe $15 in bolts, nuts, washers and wire. I know some people don't have a problem, and I'm not worried about blowing up my shop, but I hate getting shocked! I figure if I didn't do it, I'd start getting shocked, and I'd wish I did it to begin with.:BangHead: Doing it first, I won't have to go back and try it again!