Guy Posted February 23, 2011 Report Share Posted February 23, 2011 I have just recently installed the duct work for my dust collector, was wondering what everyone else's thoughts were on grounding the PVC piping. Is it needed? how to do it? and issues that you all may have had? Thanks Guy Quote Link to comment Share on other sites More sharing options...
Sac Posted February 23, 2011 Report Share Posted February 23, 2011 Dont waste your time or money grounding it. I have a 2.5HP cyclone with ALL PVC and I have no problems what so ever.. Quote Link to comment Share on other sites More sharing options...
Beechwood Chip Posted February 23, 2011 Report Share Posted February 23, 2011 I'll repeat a question I've seen asked in several forums: Does anyone know of an explosion in a hobbyist dust collector system that might have been caused by static? Not "I've heard it's a risk" or "I've heard that it happens" but "It happened to me" or "It happened to my friend." As far as I know, the grounding thing is a combination between accepted best practice for industrial dust collectors, and urban legend. That said, who wants to be the first hobbyist whose shop explodes? I think that an occasional screw point poking into the pipe would cause a lot less drag than running a wire or strap through the pipe. And since (if I recall correctly) static tends to collect on pointy things, it should work effectively. I'd choose pointy screws that protruded 1 mm or so into the pipe. Quote Link to comment Share on other sites More sharing options...
Pete Bennett Posted February 23, 2011 Report Share Posted February 23, 2011 I'll repeat a question I've seen asked in several forums: Does anyone know of an explosion in a hobbyist dust collector system that might have been caused by static? Not "I've heard it's a risk" or "I've heard that it happens" but "It happened to me" or "It happened to my friend." As far as I know, the grounding thing is a combination between accepted best practice for industrial dust collectors, and urban legend. That said, who wants to be the first hobbyist whose shop explodes? I think that an occasional screw point poking into the pipe would cause a lot less drag than running a wire or strap through the pipe. And since (if I recall correctly) static tends to collect on pointy things, it should work effectively. I'd choose pointy screws that protruded 1 mm or so into the pipe. I have checked with my insurers here in France who rightly claim to be the biggest in the world AXA and they admit they have no cases on their records of any extractor explosions or fires in workshops they can attribute to static build up in a PVC duct system. I know from my own system, now temporarily disconnected for a change to a bigger extractor, that I can get a discharge from it to me easily enough, but, I like the odd recharge to my dying batteries. Quote Link to comment Share on other sites More sharing options...
JayWC Posted February 23, 2011 Report Share Posted February 23, 2011 I'll repeat a question I've seen asked in several forums: Does anyone know of an explosion in a hobbyist dust collector system that might have been caused by static? Not "I've heard it's a risk" or "I've heard that it happens" but "It happened to me" or "It happened to my friend." As far as I know, the grounding thing is a combination between accepted best practice for industrial dust collectors, and urban legend. That said, who wants to be the first hobbyist whose shop explodes? I think that an occasional screw point poking into the pipe would cause a lot less drag than running a wire or strap through the pipe. And since (if I recall correctly) static tends to collect on pointy things, it should work effectively. I'd choose pointy screws that protruded 1 mm or so into the pipe. Honestly, I don't know any hobbyist that blew up. I think you're right in that it is from industrial or semi-pro set-ups. I did some internet research and found that the recorded cases were from large scale systems. To me if someone makes the jump from flex hose to hard-pipe of any kind, they're moving into that realm; however, I see your direction. Also, to address your comment, static tends to discharge from a point...not collect. Static tends to build fairly evenly across a field. In the post assembly period Guy is in, I think screws would be my first choice followed by the foil tape...OR nothing at all as has been pointed out twice now! I knew the "don't do anything" was coming too. That's why I included it at the end of my first post. Gotta love varying opinions and the freedom the internet provides to share them. One thing I hope we all agree on though... Never hook a grinder up to a wood collection system. Also, never use a sanding device (disc, spindle, et cetera) to dress metallic items that can cause sparks with the dust collection system on. That HAS caused hobby collectors to go boom. Quote Link to comment Share on other sites More sharing options...
thewoodwhisperer Posted February 23, 2011 Report Share Posted February 23, 2011 Some interesting reading on the topic, for those who are interested: http://home.comcast.net/~rodec/woodworking/articles/DC_myths.html Quote Link to comment Share on other sites More sharing options...
TheNehlsEnd Posted February 23, 2011 Report Share Posted February 23, 2011 I would only ground the outside to give the static electricity a path to discharge to for personal comfort, otherwise its not needed. Quote Link to comment Share on other sites More sharing options...
PaulMarcel Posted February 23, 2011 Report Share Posted February 23, 2011 I'm with Greg. I use a flexhose that has a metal slinky inside the plastic hose; I poked through from the outside to tie a ground wire from the slinky to my DC then wrapped a ground wire around the metal trash can I use for the dust. I only did it because whenever I'd walk by either, you'd feel this static draw on your skin. Too close to the trashcan and you'd get a pretty good zap. So, for comfort, but not urban legend. Quote Link to comment Share on other sites More sharing options...
budgieman Posted February 23, 2011 Report Share Posted February 23, 2011 I've never heard of anyone who has had their dust system blow up due to static discharge...plenty of "I knew a guy..." or "friend of a friend...", so I'm suitable cynical about the chance of explosion. That said, my first dust extractor was a Triton, which consisted of a large plastic bucket with a lid connected to a shop vac with plastic hose, designed specifically as a single tool collector. The first time I used it I picked it up, pulled the lid off and found a lovely soft looking pile of sawdust. Holding the bucket against my chest (who can see already where this is going?) I plunged my hand in to feel the lovely soft sawdust.....and BANG! The static shock belted me in the chest and nearly knocked me over - a real heart stopper that I'd swear I can still feel 15 years on. So my view since has since been always to ground to avoid personal injury or at worst discomfort rather than spark from explosion. Quote Link to comment Share on other sites More sharing options...
went_postal Posted February 23, 2011 Report Share Posted February 23, 2011 Any reason why you can't put a hose clamp around the outside of the pipe and ground to that? I would take a copper wire and trap it under the clamp before tightening it down... then run the wire down to the next clamp... so on and so forth. Works for flex hose... no reason you can't do it to hard line. Quote Link to comment Share on other sites More sharing options...
Dan Foster Posted February 23, 2011 Report Share Posted February 23, 2011 I would first put down foil tape and then braided wire. I did it because I was getting shocked every time I went to empty my pre-collection can. It's such a small cost for the added safety that I recommend it for every PVC system. Quote Link to comment Share on other sites More sharing options...
PaulC Posted February 23, 2011 Report Share Posted February 23, 2011 Frankly, I would be more worried about being hit by lightning, even here in Victoria, where we get no lightning. Quote Link to comment Share on other sites More sharing options...
brtech Posted February 24, 2011 Report Share Posted February 24, 2011 Any reason why you can't put a hose clamp around the outside of the pipe and ground to that? I would take a copper wire and trap it under the clamp before tightening it down... then run the wire down to the next clamp... so on and so forth. Works for flex hose... no reason you can't do it to hard line. Not likely to be very effective, but it will help some. The problem is that we're talking static electricity here. The PVC is an insulator, so grounding it every few feet helps some, but doesn't actually drain static charge. The foil tape and braid idea is pretty good - high probability of working. You might be able to get away with just a bare conductor running the length of the duct, as long as it maintained contact all along it, but contact in only one point on the circumference means you can still build up a charge. Two wires would be better (opposite sides). The tape covers the whole duct, which is why it actually works. Quote Link to comment Share on other sites More sharing options...
jmk89 Posted February 24, 2011 Report Share Posted February 24, 2011 This has been debated on the Woodworking Australia Forums too and no-one has yet been able to give an example of a fire or explosion from a dust collection system outside an industrial context where the ignition was the static buildup in the piping. Even in the industrial context where cases have occurred, the static buildup theory was only ever an alternative to causes that the investigator considered to be more likely such as a spark from a grinder or other source (eg faulty wiring in a machine hooked up to a DC system, or, most likely of all, failure by the operator to empty storage bins regularly and combustion in those bins from heat buildup from the sawdust itself. As always it's a question of making sure that the issues you are worrying about are important and real risks and that you don't ignore the real risks in dealing with the less likely or hypothetical ones. Quote Link to comment Share on other sites More sharing options...
stahlee Posted February 24, 2011 Report Share Posted February 24, 2011 It's not worth trying to ground an insulator. I've been using PVC for years without issues. After some time, the static build up will go away. Quote Link to comment Share on other sites More sharing options...
panofish Posted February 24, 2011 Report Share Posted February 24, 2011 ABSOLUTELY UNNECESSARY TO GROUND PVC OR OTHER DUST COLLECTION PIPE.... unless you dislike the occasional static shock. There is plenty supporting science on the web and magazines on this topic. If your concerned about fire... worry about your finishing rags and their proper drying. Most woodshop fires are caused by this or other typical house fire causes (electrical, smoking... etc). Quote Link to comment Share on other sites More sharing options...
Vic Posted February 24, 2011 Report Share Posted February 24, 2011 Guy, I would ground your pipe on the outside with small gauge speaker wire. The only reason I would ground is because electric static shocks fry my nervous system. The put me on edge and make me grumpy. When I was doing sheetrock in the old house I renovated, I commonly used my ShopVac attached to my 5" ROS and would wrap the 2 1/2" dust collection pipe over my shoulder. Quite a few times, I shocked the hell outta myself. As far as explosions, I think the dust from sheetrock is much more likely to reach the fine powdery substance likened to corn starch than wood dust. I didn't blow up, but on a few occasions I DID go off. Quote Link to comment Share on other sites More sharing options...
Stampy Posted February 24, 2011 Report Share Posted February 24, 2011 I'd say that for the 50 bucks worth of supplies I'd do it. Most shops have plenty of other accelerantes other than saw dust that a static spark could ignite. Static build up from the surface friction of dust could be catastophic with all the finish, thiners and paint that are near by. Frankly, I would be more worried about being hit by lightning, even here in Victoria, where we get no lightning. Actually we get lightning quite often particularily when it snows like today, you just don't hear the thunder that is normally assosiated with it. And many of the spot forest fires we get are from dry lightining. But I digress. Quote Link to comment Share on other sites More sharing options...
TimV Posted February 24, 2011 Report Share Posted February 24, 2011 Guy, Who knew that this question was going to ignite such a raging thread? I guess it really has sparked a lot of people's interest. But what we really need to do is to ground ourselves to our own reality. Don't get to relaxed, go get a cup of java and get wired. Don't let your brain get clouded by dust. It really is a piping hot issue. It is a sure thing that this won't stay static for long. It's really jumping. Go collect your thoughts and focus on the protruding points. You don't want lose your mind and blow up over this. Now for my experience: I've used pvc dc piping for years. My dc is grounded by the electrical cord. The pvc is connected to the metal dc port with a rubber boot. All of my machines are connected to the piping with plastic flex line. Although it has the metal spiral wire in the flex line, it does not directly contact either the pipe or the machine because of the plastic. I would have to say that the pvc piping, which is already an insulator, is an isolated system. Occasionally, I will get a small shock when I close a metal gate. This is exactly the same as walking across a carpet in the winter time and touching a door knob. I never get this shock when the system is running, only after I turn it off. Hmmm, at that point the dust is already in the bag (which is a good distance from the gate) and no longer airborne in the pipe. Unless you are sanding, the dc is actually collecting chips, not dust. The only dust that is on the exterior of the piping is from airborne settlement, not from static electricity. In summary, it's your choice. My shop is in my basement, directly under my two childrens' rooms. I didn't ground my pvc piping. I am more concerned about my finishing supplies and used rags. I spread out the rags until dry then place them in a sealed, metal, 5 gallon container. But the most concerning to me is my own safety in the shop (whole 'nother topic). I am comfortable with my dust collector piping being safe. Tim Quote Link to comment Share on other sites More sharing options...
Stampy Posted February 24, 2011 Report Share Posted February 24, 2011 Guy, Who knew that this question was going to ignite such a raging thread? I guess it really has sparked a lot of people's interest. But what we really need to do is to ground ourselves to our own reality. Don't get to relaxed, go get a cup of java and get wired. Don't let your brain get clouded by dust. It really is a piping hot issue. It is a sure thing that this won't stay static for long. It's really jumping. Go collect your thoughts and focus on the protruding points. You don't want lose your mind and blow up over this. All right Tim, pipe down you blow hard. This topic is exausting. I'm shocked that you could collect so much debis in one post. You've clouded the issue with ............. ahhhhhhhhh never mind......I'm going back to work................ Quote Link to comment Share on other sites More sharing options...
Sac Posted February 25, 2011 Report Share Posted February 25, 2011 Guy, Who knew that this question was going to ignite such a raging thread? I guess it really has sparked a lot of people's interest. But what we really need to do is to ground ourselves to our own reality. Don't get to relaxed, go get a cup of java and get wired. Don't let your brain get clouded by dust. It really is a piping hot issue. It is a sure thing that this won't stay static for long. It's really jumping. Go collect your thoughts and focus on the protruding points. You don't want lose your mind and blow up over this. Can I get one more pun please? Quote Link to comment Share on other sites More sharing options...
TimV Posted February 25, 2011 Report Share Posted February 25, 2011 Can I get one more pun please? Sac, I'm shocked that you aren't taking this topic seriously. Tim Quote Link to comment Share on other sites More sharing options...
Beechwood Chip Posted February 25, 2011 Report Share Posted February 25, 2011 Can I get one more pun please? Sure, the shortest distance between two puns is a straight line. Quote Link to comment Share on other sites More sharing options...
Rick LoDico Posted February 25, 2011 Report Share Posted February 25, 2011 One more reply...if it makes you nervous...ground it. For those who aren't nervous about an explosion, stay that way. It's a myth. It's never happened and never will. Quote Link to comment Share on other sites More sharing options...
Stampy Posted February 25, 2011 Report Share Posted February 25, 2011 .............and the domestication of the dog continued unabated..... Quote Link to comment Share on other sites More sharing options...
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