OK, so I figured when I formalize my dust collection for the home shop
I'll just go to Grizzly and order all the metal pipe, fittings and
blast gates I need. Going all metal I'll avoid the static problems.
Going with smooth pipe I avoid the friction loss of flex, yada, yada.
Well even with a very conservitive 2 branch run it is a bit costly.
So if I go plastic and religiously run the copper wire, etc. can I
just use standard ABS or something of the sort?
On Mar 27, 2:56 pm, firstname.lastname@example.org (Doug Miller) wrote:
Being a safety nut I'll probably do it. I have seen it detailed so
specifically in the Grizzly and other help docs. But I can be
convinced with science so maybe I'll research that while I look around
for answers about using pvc or abs.
Thanks for the reminder.
On Fri, 27 Mar 2009 14:07:32 -0700 (PDT), "SonomaProducts.com"
Safety has nothing to do with it any more than spreading scraps of
paper in your yard keeps the elephants away. Can't happen, and a
friend of mine who's at MIT wrote this article a few years ago after
conducting some experiments and running some math:
If you can find a single documented case of a home shop dust
collection system exploding you will win the grand prize of being the
first. No one else has, becuase it can't happen.
All the stories of grain elevators and factories are true. The problem
is scale. The conditions in those places (huge volume, huge quantity
of fine particulate, etc.) which can lead to static spark explosion
don't exist in any home shop--even if you have a 2000 ft^2 out
If you want a metaphor to put it in perspective, watch a movie about
ships (WWII are fine examples). Whenever it comes to explosions and
sinking, they always use models. You can always tell it's a model by
the water. Water molecules can't scale down. Splashes and foam are the
same size whether it's a model or a real ship creating them.
I generally agree w/ the article (and was going to post that a
substantial portion was published in FWW a few years ago) but you've
taken a liberty in the above statement. I haven't studied it thoroughly
to see what changes/updates have been made, but I don't believe the
conclusion drawn is "impossible", only "improbable".
It depends on the local conditions and, as noted, size and dust density.
Absolutely agree, the DC could cause a chain reaction problem other
substances other than saw dust. There are plenty of flammables in the
typical shop that only need a spark to start something undesirable.
I'm comfortable with the liberty I took. Based on Rod's article and my
paragraph noting the utter lack of evidence of it ever happening in a
home shop makes it a lock in my book. Other's books may vary.
Yes, "improbable" was Rod's conclusion. And I understand that the lack
of evidence is not evidence, but it sure is an extremely powerful
indicator when considered in conjunction with the article.
Yep, Bill Pentz's site gives pretty much the same conclusions.
However, I did like the info Bill provvided about using aluminum tape
inside and outside the length of the ducting jump grounded acrocss
joints, etc. This at least avoids getting zapped. Also, the big danger
I guess is sucking up sparks from mechanical activity. The article you
referenced speaks about how not just explosion but even more likely
smoldering fires. Yikes. I think maybe Bill's suggestion to NOT
include a floor sweep opening where you can suck up screws to spark
off the impellors is probably a good idea.
I guess I'll be adding a few fire sprinklers to my garage shop.
On Fri, 27 Mar 2009 21:56:02 GMT, email@example.com (Doug Miller)
You're right that a ground isn't necessary for safety reasons. But
think of how much static cling you get when you cut a piece of PVC
with your miter saw for example. Now imagine that static cling for
the entire run of your ungrounded dust collection piping. It makes
clean up a real bitch.
That is the only reason I grounded my system and it works great.
Bill Pentz has a recommendation on his site to run two strips of aluminum
tape along the pipe. One on the inside and one on the outside on the
same spot in the pipe. Then drill a hole through the pipe and connect
the two pieces.
Here's the link to the referenced site:
I'm working on setting up dust collection, too. I might be going
overboard, but I'll probably go with 6" PVC pipe to the machines. (I'm
also planning on a ClearVue cyclone that'll power the whole thing.)
On Usenet, no one can hear you laugh. That's a good thing, though, as
some writers are incorrigible.
I just went through this whole exercise - I didn't buy any of my
ductwork from Grizzly because they only sell the top of the line stuff
and their price is Out Of This World. Choosing not to use PVC, the only
other option I found was galvanized "snap lock". The HVAC industry uses
it, and they also carry a measly inventory of it at Lowe's Depot, but
good luck trying to find any gauge thicker than 30 at ANY of those
places (you need at least 26 gauge). I looked and LOOKED and found that
pretty much the only games in town are Penn State and KenCraft:
I bought a significant amount of stuff from both companies, and I can
tell you right now - Go with KenCraft for everything you can unless they
just don't have what you need. The quality is better and they ship it
FAST! Penn State has *some* good stuff (if you can figure it out ahead
of time from their mediocre descriptions), but some of it is crap and
they take *forever* to ship it. Let me know if you want particulars and
I can probably help you out.
Any given amount of traffic flow, no matter how
sparse, will expand to fill all available lanes.
I finished my raised floor this year and put in the snap lock ducting
from lowes/home depot. I used the regular stuff they had, it is
probably 30 gauge. I did a test by running a few lengths and shutting
off the end with a blast gate. I couldn't collapse it. My DC is the
old 220V grizzly (I think it is 2 HP). I run it directly out in the
back of the shop with no bags because I get extra suction that way. I
have had no problems with the thin stuff and I have plenty of suction
for saw, planer and jointer (not all at the same time, run through
I did have to go to 4-5 different stores to get all the correct
fittings. BTW, I ran the 6" size and use 6 to 4" reducers for the
hoses. I guess I violated every rule in Bill Pentz's book, but I have
absolutely no complaints.
That's good to know, but it would be nice if we all knew the exact
definition of "thin stuff" - 30 gauge from one vendor isn't the same as
30 gauge from another. I used my micrometer on samples of ducting from
practically every BORG and HVAC supply place within a 20 mile radius and
I wound up with almost as many thicknesses as there were samples. I
even found two different thicknesses of 6"x24" at a single Lowe's
because their supplies came from two different vendors. I bought
practically every piece of the "thicker" stuff they had because it was
cheaper (!) - they were closing it out OF COURSE (bastages!). I wound
up using a few smaller forty-fives (and what not) of the "thin stuff"
from the BORGs because of easy availability, and I figured they'd be far
less likely to collapse; I've had no trouble either, but for the longer
straight tubes I didn't want to resort to using it. Some of that tubing
is so thin you can literally bend it between the tips of your thumb and
forefinger. Knowing how much suction my 2HP Grizzly cyclone pulls I
didn't want to risk it.
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
About 3 years ago I finally added a DC, I have two 10', 4" diameter clear
flex hoses connected to it. The 2 hoses form "1", 20' hose that I simply
move to which ever tool I am using. IIRC the hose and connectors on sale
cost me about $40, 3 years ago. I have never wanted for any thing more
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