Replies

1. 
   seajai | Feb 02, 2008 07:10am | #1

   A bare copper grounding wire (18 ga. or so) run through the inside of the plastic pipe would eliminate the buildup of static inside the pipe. I have also seen this done for above ground systems as well.

    

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2. 
   hammer1 | Feb 02, 2008 04:45pm | #2

   You can't get much better grounding than actually being in the ground. I wouldn't worry about static electricity. I would worry about cleaning out, fetching a dropped arbor nut, leaking of ground water, flexibility if the machines change location, damage during the pour as well as the size of the dust collector, which will effect the size and length of the duct runs. Most shops add and move equipment around from time to time. Some of the big waste generators, like the planer often collect on top, same with a cyclone. You will have to pipe up, adding elbows and perhaps something to stabilize the duct work. It would be nice to have dust collection in the floor on a table saw, as long as you could gate it, but on many other machines, it's not necessarily an advantage.

   Beat it to fit / Paint it to match

3. 
   Bill1608 | Feb 02, 2008 06:53pm | #3

   Ducts in the floor look nicer, but really limit your options later. If I were going to put the ducts in the floor, I would make troughs in the floor. Troughs give you waaaay more flexibility. You can take the pipe out if you ever had a clog (unlikely, I admit), but more importantly, you could also lay conduit in there. Maybe some day you might find it handy to run a coax, low voltage line or air line. You never know.

   As far as static and PVC, that myth was laid to rest long ago. Not a problem for a small shop. If I had a commercial shop, I would use metal, but only because it would be non-flammable.

   One more thing. I would highly recommend using 6" pipe for your dust collector. You will waste much of your dust collectors hp if you throttle your system down with 4" pipe. I am using 6" thin wall sewer and drain pipe. I am using metal adjustable elbows, which just happen to fit nicely inside the PVC S&D pipe. I am using electrician's putty to seal the joints. Metal elbows give you much nicer bends than the standard PVC 45's. I also plan to make 15 degree wyes instead of the standard 45 degree. Run 6" pipe all the way to the machine if possible. If you have to go to 4", do it with an adapter at the machine. When it comes to flow in dust collector and vacuum systems, you get much more bang for the buck with larger duct and hose than with more hp and vacuum.

4. 
   Don01 | Feb 23, 2008 07:53pm | #4

   Bill covered most of it.
   If you have time go visit Bill Pentz' site and get educated about duct matters.

   http://www.billpentz.com/woodworking/cyclone/index.cfm

   The are also some good installation setups at:

   http://www.gallery2.clearvuecyclones.com/main.php follow Clear Vue Community - Photo Gallery

   The focus on the Clear Vue cyclones, but a few of the guys have buried their ducting in concrete.

   As Bill noted get rid of the idea of using 4" main ducting. Go 6" because eventually you will have to if you expand the number of machines and the run distances. I have read a few stories where guys have buried the 4" ducting in concrete before realizing they need 6".

   Plastic ducting is fine. You can't ground the entire pipe, only the point you are grounding. The biggest issue with static for the small shop is the zap the operator get from time to time.
   From what I have read you don't require Schedule 40 wall thickness. S&D pipe comes in lighter wall thicknesses which will save you some $. The true challenge may be to get the required Y fittings. Some guys have made their own, other get them built.
   Hope this helps.
   Don