DC ducts - 4" or 6"

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Howard-
before you go any further, read this: http://mywebpages.comcast.net/rodec/woodworking/articles/DC_myths.html
    Bridger
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Unisaw A100 said:

My balls are fine, thank you. <g> I perpetuate no myths. Good Grief, shoot the messenger. I am only reporting facts.
You will notice that I never told anyone to ground their DC system. This stupid thread started (again) over one mention of metal pipe replacing grounding the wire that some install on their PVC systems. Several companies sell DC ground kits to (IYO) misguided individuals. Fire codes in some localities require it in commercial installs. Nothing here should be construed as MY recommending anything.
As for me, I use conductive tubing, because I hate the static attraction that generic plastics generate.
Have a Happy Holiday and Peaceful New Year, Dude.
Greg G.
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Greg G wrote...

I believe that is what you think you are doing. But, for example, statements like:

can lead to confusion. It sounds like you are saying that some fire codes require commercial installations of PVC ductwork to be grounded.
AFAIK, fire codes that require grounded ductwork in commercial installations also require the ductwork itself to be metal (or at the very least, conductive). I have never heard of, and seriously doubt the existence of any code that requires non-conductive ductwork to be grounded. It just doesn't make any sense because it is impossible to "ground" an insulator.
Jim
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Jim Wilson said:

Yes, metal is *supposed* to be used in commercial installs.
But it IS possible to reduce and dissipate accumulated charges in PCV through surface leakage so that large discharges to metal objects is all but eliminated. Of course you can't "ground" PVC in the classic sense, it is an insulator. But in reality, all materials conduct electricity to some extent, especially in high humidity conditions, their resistance is just *extremely* high.
Well anyway, this thread is getting quite tedious. WAY too much grief over installing $3 worth of wire. Especially considering that the negative consequences of doing so are nil. Too bad people aren't more interested in the direction our economy or world politics is headed.
Folks, do what you want, believe what you want.
I'll stick to my conductive, impregnated plastic pipe and enjoy the peace of mind of knowing that when I brush against a pipe, I'm not going to get zapped by static discharge - which is my primary concern.
And maybe, somewhere deep down inside, I may even get some comfort in knowing that I may also avoid that 1 in 1,000,000 chance that my DC is going to catch fire. The universe is a cruel and chaotic place. <g>
Happy Holidays!
Greg G.
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Greg G wrote...

Two more points to consider. First, at least in this forum, emotion usually enjoys equal prominence on both sides of the debate. OTOH, the research and analysis conducted by some who discourage PVC "grounding" is objectively superior to that done by any who condone it.
And second, the negative consequences may not be insignificant, owing to the sizes of the probabilities involved. The probability of a dust explosion ignited by static discharge from PVC piping is vanishingly small. However, that tiny probability is increased by adding a grounded conductor on the outside of the pipe. Installing an internal conductor or screws through the piping have relatively substantial negative consequences as well. So, the likelihood of some type of undesirable incident is probably greater -- by a statistically significant margin -- when any of these things are installed.

You haven't followed any of the political discussions around here, have you? (G)
Cheers!
Jim
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The most complete treatise on this subject I have seen is located at http://mywebpages.comcast.net/rodec/woodworking/articles/DC_myths.html
This article was summarized in an issue of FWW but what is located here is much more complete. Read it and then decide for yourself whether to use PVC and whether grounding is worhtwhile.
wrote:

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In response to my statement that...

jev wrote...

Yes, that is some of the research and analysis to which I was referring. I have never seen anything comparable from any proponent of PVC DC "grounding."
Jim
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Jim Wilson wrote:

Heh heh...that's an easy one: When the "PVS DC grounding" proponents start doing serious research about dust ignition points, static discharge and grounding, one of two things happens:
1) They can't build a good argument, so they give up arguing - but still believe they are right. 2) They become "PVS DC grounding" opponents
;)
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Greg G. wrote:

You mean, you didn't write what you wrote a couple/few messages up? Bring Sybil back to the keyboard, I want to ask her something.

Facts? Please include foot notes.

So again, why do you feel there is a need for a grounding wire? Grain storage in my hobby shop dust collector?

And again, why do I need the metal ducting you recommended?

There you go. A true statement of a true fact and from everything factual that has been gathered on the subject the only real reason to choose metal over plastic. OK, to be fair there are other reasons. :-)

A'yup, and you and urine also.
UA100, who is real sorry for you that you felt you needed to state what you stated and you can't remeber what you said but what the hell, it's been real fun and the sport is priceless...
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Keeter, you forgot to tell me you are from MO.
Only believe what you see with your own eyes? Never learned anything by reading or listening to others? A fair amount of skepticism is fine, but you pretty much are calling folks liars when you refer to someone as a "myth teller".
Now I've given you reason to get back to busting my chops... :)
dave
Unisaw A100 wrote:

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Bay Area Dave said:

Aw, don't mind him. He's just a crusty old fart sparrin' for a fight. Probably didn't get any this weekend... <g>
Greg G.
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I have to needle him once in a while, Greg, to see if he'll post either a series of blank replies for a couple of days, or his infamous two word reply to me, "Bad Monkey", dazzling us all with his originality. A couple of times I mimicked his style and he came up with the well worn phrase of our youth: "monkey see, monkey do". That's why I've suggested to him time and time again to hire some new writers. :)
Greg wrote:

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Greg G. wrote:

Maybe you can deflate your blow-up doll and send it to me.
Be sure to send along the grounding wire.
UA100
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Unisaw A100 said:

SWMBO resents that...

I'll make sure to do that very thing - wouldn't want static discharge to zap wee willy. <g>
Greg G.
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Unisaw A100 said:

OK - My last words on the subject. Form your own conclusions. (Rhetorical statement for some...) Results of a 10 minute search. And not from some self-appointed expert with a misquoted web site. In this world, most anything is possible-only a fool claims otherwise.
GA Tech studied the factors behind explosions in dust collection facilities in 2002, and determined that 3 of 175 were caused by static discharge - more than defective motors and electrical panels.
Wood shop DC explosion and fire at school http://www.pburgea.org/_Articles/01-02/A06/PHS%20Wood%20Shop%20Fire.htm
Exploding DC Ducts in Woodshop See Post by David Snow http://www.talkshopbot.com/messages/26/801.html
Explosion in DC in MFG http://www.sharon-herald.com/localnews/recentnews/0010/ln102000c.html
General Info on dust/ignition http://www.warren-group.com/articles/grainpartI.html
Grounding of Dust Collectors and ducts/plastic/static producing parts See Section 5.12.1.4 http://www.ccbfc.org/ccbfc/committees/former_SC/hazardous/minutes/minutes_9402_E.shtml
As far as I'm concerned, $3 is cheap insurance against these sorts of things - in addition to the reduction in unpleasant static discharge to your person.
Ciao,
Greg G.
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Greg G. wrote:

Wait! Is it? Call me a skeptic but it seems I read this somewhere else.
http://www.pburgea.org/_Articles/01-02/A06/PHS%20Wood%20Shop%20Fire.htm http://www.talkshopbot.com/messages/26/801.html http://www.sharon-herald.com/localnews/recentnews/0010/ln102000c.html http://www.warren-group.com/articles/grainpartI.html http://www.ccbfc.org/ccbfc/committees/former_SC/hazardous/minutes/minutes_9402_E.shtml
And in which of these was PVC cited as the culprit?

Agreed when you cite static discharge.

Probably not given your track record to date.
UA100
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<Greg G.> wrote in message

You've handled yourself well on this subject, Greg ... showed common sense, class, and a good deal more charity and than most.
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Swingman said:

Thanks, but not a subject I *really* wanted to get involved it, nor a fervent believer in. As I mentioned, just playing devil's advocate for another side for the coin - one in which there in no *real* undisputable scientific evidence to support either side. Life is chaotic - I believe anything can happen, if circumstances permit.
Many of the discussions here devolve into bouts of name calling and personal attacks - often fairly quickly. IMHO, not a good way to present either side of a debate.
Now don't get me started on left tilt vs. right tilt. <g>
Greg G.
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Greg G. wrote:

Both! One of each! Two of each! <g> Three saws that tilt both ways! <g>
-- Mark
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I don't get it. I can understand wanting a left and a right, and it certainly makes sense to have two of each (set up for rip and crosscut), but I don't see what you're going to do with the third of each. Do you really cut that many dados?
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