Replies

1. 
   donpapenburg | Dec 06, 2005 04:42am | #1

   Will the pipe be any place that you can touch it? Do you like surprises?  PVC will build up a good static charge that will snap as it discharges into your unsuspecting body.  Some of them will make you say colorful words.

1. 
   stewart | Dec 06, 2005 03:30pm | #2

   The pipe will be run under the floor and pop up at each machine but there will be short pieces of it here and there that will be exposed. How long does the charge remain after the tool has been shut off?

2. 
   sailalex | Dec 06, 2005 04:19pm | #3

   I got the copper wire when I got my DC system about 4 years ago but due to my laziness, I haven't attached it and left it in the bag. I haven't seen any static discharge in that time. Maybe , like me, just get a coil of wire and leave it in the bag. :)

1. 
   stewart | Dec 07, 2005 01:36am | #4

   Sure! I'll leave next to the coffee can of assorted screws and hardware that I'm getting ready to sort out.

2. 
   mudman | Dec 16, 2005 07:01pm | #5

   LOL. That gave me a good laugh.

   Mike

3. 
   seattlewood | Dec 17, 2005 09:42pm | #6

   I'm getting ready to instal my own DC system and have been reading a ton on Dust collection lately, mostly from Bill Pentz's website "http://billpentz.com/woodworking/cyclone/index.cfm" (worth a read, lots of DC info) and he also talks about the myth of static discharge. However, if you go by his research, you'll need to use 6" ducting and high CFM. This will have a much higher chance of creating static that, while it probably won't cause any explosions, could definitely give you a nasty shock. But, on the other hand, when you put that stuff under concrete, it will already be grounded, so the outside of the ducts will discharge constantly. I'd say you're pretty safe.

   Nick

1. 
   highfigh | Dec 17, 2005 10:01pm | #7

   Are you using metallic ducting? If you are, parasitic charges will erode the metal till it's perforated, just like an outboard boat motor with bad anodes. If it lasts that long. Concrete on metal ends up with the concrete winning, eventually. If you're using plastic, the outside of the duct being grounded does absolutely no good. Plastic is an insulator and it's the air with dust suspended that could become an explosion risk. Wood is fuel. Air supports combustion. Fine wood dust suspended in air is a fuel/air mixture and if it's in the right ratio and the relative humidity is low enough, it could go up. What are Bill Pentz's qualifications regarding static discharge and whether it's a hazard or not? (OK, I read part of his site and he isn't an engineer.) He talks about the ducts plugging because of an internally located ground wire and I have yet to experience this with my measly 4" lines. Under the right circumstances, it could happen. Extremely cold, dry air, especially when it's been heated with dry heat (Hot Dawg, Modine, etc) makes the static discharge more intense and the dust particles more likely to ignite. It just takes one time and I'd perfer to err on the safe side. I hope the reason people don't run a ground wire isn't due to the fact that they can't figure out how to get the wire to the other end. If it is, it shows a complete lack of ingenuity. If it's because a wire would cost about a dollar, that's just stupid.
   "I cut this piece four times and it's still too short."

   Edited 12/17/2005 2:17 pm by highfigh

1. 
   seattlewood | Dec 17, 2005 10:28pm | #8

   I'm personally planning on using PVC, mostly because of cost and the fact that it is one of the best pipes for not decreasing airflow because of the smooth walls. I agree that metal under a concrete floor could be a problem in the long term, plus, you'd have to situate the ducts exactly, and the machine can't be moved... just a thought.I'm in full agreement with you, it's definitely possible under the right circumstances, I think it's just that those circumstances are unlikely. As for Bill qualifications on Static... not sure. He primarily references a FWW article anyway, so it's really not his qualifications that are in question. The article is on this network, search for "static", it's worth the 2 page read. Despite that, Bill's qualificaitons are mostly in dust collection itself (see his site), and the main thing is that he states we should all be using 6" main ducting to get the proper airflow to collect fine wood dust. Considering the FWW article was for 4" ducting, I'm willing to go the extra effort and ground my PVC. On Bill's site, someone wrote a little how-to on grounding the system with aluminum tape, seemed like a pretty slick solution, I'm planning giving that a try.

1. 
   seattlewood | Dec 17, 2005 10:40pm | #9

   One more thing I wish to point out (in Bill's defense) is that he is an engineer... actually, he's multiple. He has a BS in both Mechanical Engr and Computer Hardware engr, and MS in both Hardware and Software engineering. He also has minors in Electrical Engr, Physics, math, Psychology, Philosophy, Art and Biochemistry.I'm afraid I have to give the guy a little credit, that's a lot of school.

1. 
   highfigh | Dec 17, 2005 11:54pm | #10

   I don't have a problem with his qualifications regarding removing dust and getting it out of the woodworking environment, but I do think using a ground wire is the best way to go. Whatever form it takes, a way to effectively dissipate static electricity is a good idea. The aluminum tape sounds like a good way to do it, but it seems difficult to make good contact over the entire area of the tape. A ground wire doesn't have this problem, but he talks about plugging the duct. I'm trying to figure out how large the wood pieces are that get into his duct. Most likely, thin stripsthat are the same width as the wood is thick, but they can't be too long or they won't make the bend into the duct going from the cabinet. Once dust hits the strips, I would think they make the strips travel along the duct until they reach an edge (if there is one) or the cyclone. That is, if he has the amount of air volume I think he does. My whole point is, our gas grills and range burners use a spark to ignite the fuel. Why is it hard to see that if static discharges in a duct where there is fuel it could be a problem, whether that fuel is wood dust, solvent fumes, lint or something else. As I said before, I'll err on the side of safety and keep my ducting bonded. "I cut this piece four times and it's still too short."

   Edited 12/17/2005 4:13 pm by highfigh

2. 
   seattlewood | Dec 18, 2005 12:16am | #11

   I'm sorry Highfigh, I beg to differ. He states that he is not an AIR engineer. But he is definitely an engineer, look at his Home page in the "too much about me section" http://billpentz.com/Look, this really isn't the point of this thread, I was simply trying to assist our fellow woodworkers in finding out for themselves some information on Dust collection. I consider Bill's site to be a wealth of knowledge on that subject. On the topic of grounding, I think he does a good job of referring to others, in this case, our friends at Fine woodworking, a another group of people I highly respect.As for grounding, I'm still of the mind that you can never be too safe, and grounding your dust collection system is never stupid maneuver, I just wanted to share some info I have gained in recent weeks.Edit: I wrote this the same time you did your post, sorry for the loss of continuity. Well put, I think you and I definitely agree on the fact that taking an additional safety measure in our Home shops is a prudent venture. NickEdited 12/17/2005 4:18 pm ET by seattlewood

   Edited 12/17/2005 4:21 pm ET by seattlewood

3. 
   highfigh | Dec 18, 2005 12:21am | #12

   FYI, I edited my post after re-reading his site and did see his comment about not being an air engineer and that his career was spent doing engineering and research. His quest for the ultimate dust removal system is understandable, in light of his health issues and love of woodworking. You're right, we do agree that being safe is the best way. If you look in the workshop threads, there's one about a public school woodshop where the writer of the thread had been going there when it was not being used and saw that the TS blade had been left up and had no blade guard. After asking for recommendations on what to do about it, he went in to recommend that this be changed and the problem has been solved. He was banned from the woodshop. Makes me wonder if they use push sticks.

   "I cut this piece four times and it's still too short."

   Edited 12/17/2005 4:30 pm by highfigh

2. 
   stewart | Dec 28, 2005 02:19am | #14

   You raise a good point and that is why I posed the question in the first place. I am only recently familiar with Bill's dust site - I got the original notion of a ground wire being unnecessary from Canadian Woodworking but I have no knowledge as to what the author's education or experience was. I remember being a young boy and hearing that the local feed mill exploded and what a revelation it was that grain dust was explosive. My initial thought was with the large numbers of woodworkers who follow these discussions that if the threat of explosion was more than theory someone would have had a personal experience with it or would have known someone who did.

    With the PVC pipes runniing beneath the building I wonder what would happen if I drilled holes at 8' intervals inserting a wire into the air stream and then wrap an 8" spike and hammer it into the ground.

   Edited 12/27/2005 6:28 pm ET by stewart

1. 
   highfigh | Dec 28, 2005 03:47am | #15

   You don't need to do all of that to run a ground wire. Run it through and leave some extra on each end and if it ever gets clogged, just pull the wire from one side to dislodge the piece that's causing the problem. I used stranded wire and have had no problems with strips of wood becoming stuck.
   "I cut this piece four times and it's still too short."

2. 
   stewart | Dec 28, 2005 02:09am | #13

   Thanks for the imput and sorry it has taken me so long to get back to you - Christmas you know. I took your advice and checked out the site and then I went out and ordered $500 worth of 6" pipe and fittings. I had no idea about that stuff - I just assumed that since 4" material was so available that it was the way to go. My building is raised so my piping will not be grounded though it would be a relatively simple matter to ground the outside at any rate. My wood supplier just went out of buisness as he developed a sensitivity to wood dust and I am determined to take the steps necessary to avoid going down that road. Buying PVC does not stir the imagination the way buying a new tool will however.

4. 
   Pop | Dec 28, 2005 02:42pm | #16

        Hi Stewart,

   Its not so much that a dust explosion bothers me, its "FIRE" that makes me a little nervous! When I was a Scout, we were taught to make a fire by friction. Once you had an amber of fire, you would blow air into it until it went to full flame! I think all those ingredients can be found in various wood working equipment! Friction, heat, fuel, and oxygen. There is always a little sawdust, woodchips in the dust removal equipment, and now you want to add plastic? Me, I will stick to the metal duct work, and watch the sawdust removal equipment go up in flame! (I'm laughing out loud)  Pop

5. 
   cowtown | Jan 02, 2006 09:25am | #17

   I've heard the chatter about fire hazard, with static discharge in DC systems, and  I cannot add anything to that part of the discussion, but  I'd bet that the risks of fire are maybe significantly greater if you consider what would happen if a wayward screw got caught between the impeller and the housing. Lottsa sparks, lotsa air, lotsa combustibles. Sometimes the DC is outside where you can't see it.....

   OTOH, here in Calgary, it is dry, heck even the rain and snow is dry. Static is a fact of life.

   I got kinda used to the odd "intensive" shock or five when vacuuming the shop or site, but what prompted me to insert the wire into the plastic vacuum cleaner hose was the zap that happened to shoot through the sole of my work boots as I was sanding. It became a comfort thing. Problem disappeared.

   Eric

1. 
   sawdustmfg | Jan 04, 2006 09:01am | #18

   I have read this thread concerning the ground wire. I am a little confused about whether to ground mine or not. One question that comes up concerning my system is, why can't I just ground to the re-inforcement wire molded into the hose? Would that be sufficient ground or does the ground wire actually need to be exposed to the sawdust path?

1. 
   woodlark | Jan 05, 2006 12:01am | #19

   I'm no expert. However, a friend of mine who is a physicist told me that the static electricity is a "field". On his recommedation, I coiled a bare copper wire around the OUTSIDE of my PVC pipe. This avoided the problem of the wire interfering with dust collection.I attached it to the electrical ground at outlets. I never did get a static shock from the system. It makes sense to me - after all, when you do get a shock from your PVC pipe, YOU are touching it from the outside.

1. 
   sawdustmfg | Jan 05, 2006 07:23am | #20

   Gotta agree with that logic, thank you for the reply.

2. 
   Pop | Jan 05, 2006 04:56pm | #21

        Hello Sawdustmfg,

   I know that plastic acts as an insulator. When saw dust and wood chips pass through the "Plastic tube" it can, and will generate a stored electrical charge, inside the plastic tube. You have experience this charge, walking across a rug, then touching a door knob, "POW!" Last I read, that charge was measured somewhere between 15 and 25,000 volts! Think of it this way, electricity traveling through the greatest insulator on this planet, the AIR, between your two fingers, and it is stored inside your plastic tubing. Run the wire through the plastic tubing, and then to a UL approved Ground. But if you used a metal duct, no problem. I often wonder, however, sometimes folks invent problems just to sell a product. I myself, never heard of some wood cutters sawdust removel system exploding in their face, or going up in smoke, do to this static charge. I hope there are some readers, on this line who can contribute such stories to this subject.  Me, I will use the metal duct....... Pop

1. 
   highfigh | Jan 05, 2006 07:06pm | #22

   You haven't heard of anyone it has happened to, but do you really want to be the one? All things considered, I would rather keep it from happening even if the chances are astronomically high against it, especially since it took about five minutes to run and attach it.
   "I cut this piece four times and it's still too short."

1. 
   tinkerer2 | Jan 06, 2006 04:07am | #23

        You and I would probably would take the safe road.  But don't you think a study by university or other group would be made to determine the possibility of fire or explosion from a non grounded system.  If not possible, then we might be sacrificing a lot of money or convenience on the wrong assumption that plastic is dangerous.  I would like to know.

2. 
   highfigh | Jan 06, 2006 04:35am | #24

   It's not that plastic is dangerous, but because metal conducts, a ground wire isn't needed. There's no reason for a study and it takes about 10 minutes, $1.00 worth of wire & connectors and the desire for safety to ground the machines. I grounded mine because I got the crap shocked out of me repeatedly when I first fired up my dust collector and I don't want it to happen again.
   "I cut this piece four times and it's still too short."

3. 
   tinkerer2 | Jan 06, 2006 05:26am | #25

        Shocked the crap out of you?  Sounds like the study has already been made.  Thanks for the info.  I will be putting in a dust collector and all these little pieces of info help.

4. 
   Pop | Jan 06, 2006 03:44pm | #27

       Dear Highfigh,

   I hear what your saying, and I agree. But on the other hand,  there is always someone tring to scare you into a corner for their own gratification. Me, I don't like plastic or flexable duct for saw dust removal equipment. I would for instance, like to know how many hobby and commercial shops went up in smoke do to ungrouded  plastic duct. I'm just curious. I have just built a garage/woodshop. I plan on using metal duct, and some flexable pipe (as short as I can keep it) connections between the metal duct work and equipment, until I settle into where all my equipment finds a permanent home, then it will attached to the wooden floor. The metal duct work, will be located under the floor, in the crawl space. I am a sailor, and they tell me that a 26 pound anchor will hold my boat, I will bought a 36 pound anchor, I look at it as add insurance, it didn't cost that much more. I look for that peace of mind, as you do..........Pop

    

3. 
   cowtown | Jan 06, 2006 09:28am | #26

   you was askin...

   I have read this thread concerning the ground wire. I am a little confused about whether to ground mine or not. One question that comes up concerning my system is, why can't I just ground to the re-inforcement wire molded into the hose? Would that be sufficient ground or does the ground wire actually need to be exposed to the sawdust path?

   .............................

    

   I ain't no expert by any stretch of anyones imagination. . A lot of my hoses don't have any re-inforcement wires in em, so nothing to connect to. It would be reasonable to think that if you got a metal re-inforcing wire, you could ground it. Wouldn't likley hurt....

    

   And as fer using metal conduit, well, I just never figured out the way to hook up rigid metal conduit to any of my sanders, either fixed or portable, and still be able to use em.

    

   dunno if that illuminates anything for ya, but them wires sure make my life a tad more tolerable.....

   Eric

    

1. 
   Pop | Jan 06, 2006 04:01pm | #28

     Hi Cowtown,

       The reinforcing wire found in the flexable air duct, is not copper wire. Which means it has a higher resistance to a electrial charge, or in other words its harder to conduct elecricity, which that static charge in the plastic duct work is. The manufacturs of this gound wire for plastic duct, give specific insturstions for runing the wire, copper, through the inside of the pipe to a proper earth ground. I'm thinking they must know something.  Good luck and take out some fire insurance on your shop. LOL........Pop

2. 
   sawdustmfg | Jan 07, 2006 09:37pm | #29

   Eric

   Thanks for the reply. I agree the metal ducting doesn't work for me either.  I think I will solder a lead to the wire on each end of the hose's reinforcemnt wire and see if I get shocked, if I do, then I'll find a suitable plan "B".

    

   Edited 1/9/2006 11:13 am ET by sawdustmfg