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Even if you’ve never dealt with ductwork before, you won’t have any
trouble putting up your system. Be sure to wear leather gloves when
handling sheet-metal parts. The metal edges can be razor sharp.
Specialty Tools and Hardware
There are a couple of specialized tools you’ll want for this job (Photo 1).
The
only power tools you’ll need are a drill for fastening the sections and
a jigsaw for cutting the pipe to length. If you don’t own a jigsaw, a
reciprocating saw or a pair of tin snips will do the trick.
Start at the Collector
Most
1-1/2- to 2-hp collectors have 5-in. inlets. It’s best to run
5-in.-dia. pipe all the way to the tool, and use a reducer to step down
to a 4-in. port, if necessary.
If your collector has a 6-in. inlet, start with a 6-in. line. After the first branch, step down to 5
in. and stick with that diameter until you get to the machines. A
common mistake is to run 6 in. everywhere. Just because a 1-1/2- or
2-hp collector has a 6-in. inlet, doesn’t mean it has the power to run
a central system made entirely with 6-in. pipe. Also, most small shop
tools have 4-in. ports. When the airflow from a 4-in. port hits the
6-in. duct, the air speed is almost cut in half. The slow air speed can
result in dust settling out in your duct.
If your shop is larger
than 500 sq. ft. or you have a large machine like an 18-in. planer or a
24-in. drum sander, play it safe and buy a 2-hp collector with a 6-in.
or larger inlet. Big tools like an 18-in. planer or a 24-in. drum
sander will max out a small system. Locate big-draw tools as close to
the dust collector as possible and run 6-in. duct right to the tool.
Assemble and Hang the Ductwork
The
straight pipe we used has to be assembled, but it’s no big deal. It
takes a matter of seconds to snap together a section of pipe (Photo 2).
Run the pipe with the crimped end pointing downstream toward the
collector. We recommend mounting blocks and metal hanger strap to
secure the duct to the wall (Photo 3).
To join the pipe and
fittings we found self-drilling sheet metal screws to be just the
ticket (Photo 4). Don’t worry about the screw ends protruding into the
pipe, they’re too small to matter.
Use metal hanger strap every 3 to 4
ft. to suspend the ductwork from the ceiling (Photo 5).
45-Degree Wyes
Use
45-degree wyes to create drops to each machine and to start branch
lines. These are the “entrance ramps” to your dust-collection
freeway. They allow the air stream to change directions without abrupt
turns.
Cutting the Pipe
Cutting pipe with a jigsaw makes one
heck of a racket. Don’t be surprised if the noise attracts curious
neighbors and family members. (It’s the perfect opportunity to ask for
a little help putting up that ceiling run.) We found a jigsaw with a
metal-cutting blade gave the best results with the least hassle (Photo
6).
Elbows
Use adjustable, large-radius elbows to make those
gentle turns. They cost less than fixed elbows ($10 vs. $17) and
because they’re adjustable, there’s no need to special order 45- or 30-degree elbows. The first time I tried to change a 90-degree into a 45-degree elbow, I
ended up with a mess. The key is to turn each section 90 degrees and
alternate the direction each section is turned to produce a smooth 45-degree elbow (Photo 7). To get a 30-degree sweep, turn each section 120 degrees instead of 90 degrees. Tip: Loosen the joints by gently tapping the ends of the elbow on a flat surface.
Blast Gates and Flex Hose
At
the point where a line branches off to serve a single machine (usually
at a 45-degree wye) we added a blast gate, blast-gate adapter and flex
hose (Photo 8). Attach the flex hose with adjustable hose clamps. Flex
hose is expensive ($5 per ft. for 5-in. dia.) so keep it as short as
possible. If you know your machine isn’t going anywhere, run rigid pipe
right to the tool.
We recommend using flex hose with an imbedded
metal coil and keeping the lengths under 5 ft. The metal coil and short
length will keep electrostatic discharge to a minimum. To completely
ground the system, just peel back the plastic to expose the wire at
each end. Bend the exposed wire into a loop and screw it to the metal
pipe on one end and the machine’s dust port on the other.
Seal all the joints with silicone (Photo 10). If your pipe seems a bit oily, clean the joints with a little vinegar first.
Modifying the Dust Ports on Your Machines
You’ll find most of the dust ports on your machines require some modification. For example, in our shop, we swapped out the 4-in.
plastic port on our jointer with a 5-in. flange bolted to a piece of
plywood. We also added a 4-in. dust port to the bandsaw and made a hood
for the chop saw (Photo 11).
We split the 5-in. duct to the tablesaw with a 5 in. x 4 in. x 3 in. 45-degree wye joint and a 3- to 2-in. reducer. A 4-in. hose collects from the open area at the base of the saw while a 2-in.
hose collects off of the overarm guard. The overarm guard
makes a huge difference. It literally captures and whisks away all that
stuff that gets thrown back at you from the saw blade.
Machines
with a 4-in. dust port require a reducer fitting. Place a
reducer as close to the machine as possible to ensure maximum cfm to
the machine.
Once everything’s attached, you’ll be free at last
from the tyranny of the broom and dust mask! No more dust tracked all
over the house either. One last tip—get a remote control for the dust collector. With your
new dust-collection system and a remote, woodworking’s never been so
good
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