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Avoid inferior metal duct that requires you to cut it
to length and snap it together. This type of duct is
time consuming to install because it requires you
to seal all the seams with silicone and screw the
components on the ends with sheet metal screws.
Another disadvantage is the rough internal seams
and
crimped ends that unavoidably increase
static pressure.
Figure 10. Examples of metal pipe and
components.
Plastic Duct
Plastic duct is also a popular material for home
shops. One problem with using plastic is that it is
less efficient per foot than metal. The popularity of
plastic duct is due to the fact that it is an economi-
cal and readily available product. It is also simple
to assemble and easily sealed against air loss.
The primary disadvantage of plastic duct for dust
collection is the inherent danger of static electrical
build-up, which can lead to fire or explosion if not
correctly grounded.
Figure 11. Plastic duct and components.
G5954 5HP Dust Collector
Flexible Duct
Flexible hose is generally used for short runs,
small shops and at rigid duct-to-tool connections.
There are many different types of flex hose on
the market today. These are manufactured from
materials such as polyethylene, PVC, cloth hose
dipped in rubber and even metal, including steel
and aluminum.
Figure 12. Example of flexible metal duct.
The superior choice here is metal flex hose that
is designed to be flexible, yet be as smooth as
possible to reduce static pressure loss. There are
also many kinds of plastic flexible hose, such as
non-perforated drainage type hose and dryer vent
hose. Drainage type hose, while being economi-
cal, does not quite have the flexibility required
for dust collection. The inside of the duct is also
deeply corrugated and can increase the static
pressure loss by as much as 50% over smooth
wall duct. Dryer vent hose, while being completely
flexible, is non-resistant to abrasion and has a
tendency to collapse in a negative pressure sys-
tem. We DO NOT recommend using dryer vent
hose in your dust collection system.
If using flex-hose, you should choose one of the
many types that are designed specifically for
the movement of solid particles, i.e. dust, grains
and plastics. However, the cost of specifically
designed flexible duct can vary greatly. Grizzly
offers polyethylene hose, which is well suited for
the removal of particulate matter, especially saw-
dust, since it is durable and completely flexible.
Polyethylene is also very economical and avail-
able in a wide variety of diameters and lengths for
most applications.
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