I have been using a Cummings 1 hp dust machine with 4" pvc pipe for about 5 years. When I first installed the system I put the copper wire throughout the system but eventually removed it because it was constantly stopping the flow. I just received a 2 hp Grizzly that will replace the Cummings. I know the reason behind the copper wire and need to ground the system. My question is how many of us have or at the current time are running their systems without them being grounded. Is the need as great for a small shop as it would be for a much larger system, example a 3 or 5 hp machine? Is it like the warnings on a prescription, it needs to be there to remove the liability for the maker of the system? Could the copper go on the outside? And lastly, does anyone know of a possible place to buy the wire without having to order? My completed system runs through approximately 75 to 80 feet of pvc pipe. Appreciate the thoughts.
Static electricity in dust systems
- Thread starter lwhughes149
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As explained in the article Andy posted, from a safety point of view there is no need to ground your duct work in a home shop. Now, anytime you move dust through plastic (whether it's a DC or shop vac), you can build up static electricity that can zap you. Uncomfortable but not really dangerous. This happens more frequently when the air is dry. Some people have reported that "grounding" the pipe with copper wire helps, others didn't find it useful. Since the only practical purpose is to avoid getting shocked, you'd want the wire on the outside. A strip of metal foil tape might also work.
I've had PVC for a couple of years and never had any issues. The zapping becomes less of a problem once the pipe is coated with dust.
I've had PVC for a couple of years and never had any issues. The zapping becomes less of a problem once the pipe is coated with dust.
M
McRabbet
Lorraine,
I'd suggest you read the information in this link found in our Link Library WW Reference category. I have never encountered static problems with PVC in my 35+ years of using dust collectors. I did build a chip collector that I've used in line with my planer and jointer to capture the coarse material and in the design from Shop Notes, it has a copper wire between the inlet and outlet ports to connect to the wire in the flex -- I have never connected that wire (shown in the photo below) and have never received a shock when I've changed the inlet flex from one tool to another. Any static that does build up can be easily discharged with a screwdriver from the wire in the flex to the metal part of a power tool.
I'd suggest you read the information in this link found in our Link Library WW Reference category. I have never encountered static problems with PVC in my 35+ years of using dust collectors. I did build a chip collector that I've used in line with my planer and jointer to capture the coarse material and in the design from Shop Notes, it has a copper wire between the inlet and outlet ports to connect to the wire in the flex -- I have never connected that wire (shown in the photo below) and have never received a shock when I've changed the inlet flex from one tool to another. Any static that does build up can be easily discharged with a screwdriver from the wire in the flex to the metal part of a power tool.
Thanks guys, this makes my life easier. No copper for me. I do have a separator that will be included with the system for the large particles, maybe I will ground that to the machine. thanks again
I did some research on this when I was setting up my shop, and what I discovered is that unless you are exceeding 1500 fpm through your system, it will not build up sufficient joules of energy to cause a problem.
Over 1500 cfm, coupled with fine dust (such as from a wide belt sander), and you may have a problem.
Typically, your system needs to be larger than 5 hp in order to pull 1500 cfm or greater. You also need enough inlet area to allow the system to flow that much.
Bottom line, for a home shop it should not be an issue.
Over 1500 cfm, coupled with fine dust (such as from a wide belt sander), and you may have a problem.
Typically, your system needs to be larger than 5 hp in order to pull 1500 cfm or greater. You also need enough inlet area to allow the system to flow that much.
Bottom line, for a home shop it should not be an issue.
May I pose one additional question? I have a separator with the new machine, it calls for a metal can, is that necessary, will a plastic can do just as well? I have several plastic cans handy and hate to spend the money if it isn't necessary.
I use a plastic can for mine and have had no issues. the can is a brute from rubbermade. my DC only pulls 650CFM and is not grounded. I get a jolt every once in a while but it isnt enough to hurt. :gar-Bi
Thanks Fred, guess one of those extra cans will be coming into the shop tomorrow. I am so excited about getting that new machine up and going. If anyone sees a reason for the metal can please ring in. Thanks again Fred.
as a caution be sure to not close all the blast gates at the same time when the DC is running....:gar-La; even the metal cans dont like that.....
But it is kinda fun to watch. :gar-La;
M
McRabbet
With a small DC like the one you have, a good plastic chip bin, a fiber drum or a metal ash can will usually do well, but the higher static pressure of a large system or a cyclone can easily crush one even if one or more blast gates are open. Even a Brute by Rubbermaid often cannot survive. Heavy linear polyethylene drums made for food or chemical service are much more robust for those applications.
I had an old 8 gal plastic vac that I changed into an in-line collector with my current vac, to slow down emptying when I use my thickness planer. When I would take the top off, the chips would jump out like popcorn popping (although I never got "zapped") due to static. I now use a 10 gal metal can with a Thien-type separator on it. The chips still have some charge, but not nearly as much (they don't jump out of the can).
The only caution I would give is to not mess with the system whenever the shop has a lot of highly volatile fumes in it (i.e acetone, lacquer thinner, etc). If there is a chance of a static spark of any size, you do not want it to happen soon after using a spray can, or if you are holding a rag wet with acetone.
JMTCW
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The only caution I would give is to not mess with the system whenever the shop has a lot of highly volatile fumes in it (i.e acetone, lacquer thinner, etc). If there is a chance of a static spark of any size, you do not want it to happen soon after using a spray can, or if you are holding a rag wet with acetone.
JMTCW
Go
Lots of good information guys. As I said earlier I have several plastic trash cans but I also have one that is heavy duty that once had chemicals in it but the top of the container is sealed, don't know if I can get it off. I will look at that. If I manage to remove the top, if it quite heavy for a woman to empty so the question is, can I line it with a leaf bag?
You may be better off putting the can on a platform with wheels.
The suction from the DC can easily pull a plastic bag out of the container if you don't have some way to keep it anchored. And even if you have some way to keep the bag in the container, that doesn't make the chips in the bag any easier to carry.
The Brute container that I used to use had the 5 wheel base on it. The fiber drum I use with my cyclone now I transport with a hand truck. Wheels is the way to go.
The suction from the DC can easily pull a plastic bag out of the container if you don't have some way to keep it anchored. And even if you have some way to keep the bag in the container, that doesn't make the chips in the bag any easier to carry.
The Brute container that I used to use had the 5 wheel base on it. The fiber drum I use with my cyclone now I transport with a hand truck. Wheels is the way to go.
M
McRabbet
I have a few of these heavy drums that the top has been removed with a coarse jigsaw blade (some of the polyethylene is > 1/2" thick!). Unfortunately, the top opening is smaller that the middle of the barrel and a leaf bag could not be removed when full. I also have one that is cylindrical that had a full diametr top and 55 gal barrel bags do work in itbarrel side . If you cannot find a cylindrical plastic barrel, try to find a steel drum -- they are made in 55 gallon sizes, but also smaller ones, too. While also heavy, they should accept a plastic bag you could remove.
Another option to consider with leaf bags is a heavy plastic sheet of plastic that is inserted into the bag that has been placed in the barrel. It sandwiches the bag against the barrel sides; when the dust bin is filled, the sheet of plastic is pulled out and then the bag. They are available from Ace Hardware.
BTW, I use a hand truck to move my full bins, because they are too heavy to carry!
One thing to remember, all it takes is one small spark and a bit of dust to cause an explosion and wood dust is highly explosive. A few minutes of grounding the system could prevent a lot of grief down the road. Just because it hasn't happened to anyone yet doesn't mean that it won't at some point in time. The insurance and peace of mind will be rather cheap as compared to the possible results.
Just my 2 cents worth. And, my system is fully grounded!
Just my 2 cents worth. And, my system is fully grounded!
Question - when static energy is created, do the electrons file onto the copper wire in an orderly fashion or does running a wire through guarantee that you have sparks, just lots of smaller ones inside the tube where the dust is instead of an occasional larger one outside the tube where there isn't much dust in the air? Keep in mind that a static charge does not create a spark; a static discharge does. So I wonder if adapting the system so it can discharge at any and every point is the best idea or not.
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