Workshop Dust Control
An introduction to the methods and strategies for
effective dust control.
Whether you're working in a commercial woodworking shop,
or on the first project in your garage, dust control is an important
issue. With repercussion ranging from dust in your finish to potential
health issues, dust control tools and measures have become more prominent
in woodworking over the last decade. The good news is that the vast
majority of dust can be controlled with a few simple steps.
Reasons to Control Dust:
Health Effects
The health effects of long-term exposure to wood dust are the primary
reason to control dust in your workshop. When I was in high school I
worked in a lumberyard cutting wood for customers. I never wore any
hearing or dust protection equipment. I discovered that after about four
years I was more sensitive to the dust and would become congested and
tight in my chest.
Now I wear a respirator whenever I work with wood. I
discovered later that my experience is not unique. I've heard many stories
from professional woodworkers who have had to retire due to severe
allergies stemming from decades of working without any form of dust
control. Beyond simple allergic reactions other health effects include:
Eye & Skin Irritation, Respiratory Effects, Nasal Cancer and increased
sensitivity.
Fire Risk
Sawdust poses a serious fire hazard in a workshop. Wood is flammable and
the light powdery dust form it can burn very quickly and with explosive
force. If wood dust is concentrated heavily in the air, and then exposed
to a spark, it can cause an explosion. The fire jumps from particle to
particle in a similar manner as a grain silo explosion. Fortunately this
is not very common. Sawdust lying around your shop is more likely to catch
fire and burn from a stray spark or flame.
Slipping Hazard
Sawdust on a smooth floor can become slippery and cause accidents.
Dust in Finishes
If your trying to achieve a smooth "piano like" finish it
will not be possible with dust in the workshop. The dust will settle on
your finish and leave imperfections.
Tool Life
Dust collected in power tools can reduce their lifespan. The dust can
block air ports and get into the internal parts thus shortening their
life. The best way to control this is to draw the dust away from the tool
with a vacuum during use. (More on this later) You should also use
compressed air (or a vacuum) to blow dust out of the inside of the tool.
Regulatory
If you run a commercial woodworking shop, dust control is the law. There
are various regulations covering employee's exposure to dust in the
workplace. Effective dust control is required to comply with these laws
and avoid heavy OSHA fines.
Checking for Dust in the Shop
Still not convinced that you need to control the dust in your workshop?
Then try this simple test. After a day of working in your shop turn off
the lights and use a bright flashlight or a laser pointer. You will see
all of the particles in the path of the light beam. Keep in mind that this
is the same air that you're breathing! You either need to remove the dust
from air or your lungs will do it for you! Note: This simple test is
useful for determining if your shop is clean enough for applying a finish
to your project.
Types of Dust
There are three types of "dust" that you will encounter in your
workshop. Each of these requires a slightly different control strategy.
Shavings
Wood shavings are typically created by planeing wood by hand. These shavings are long and curly. Shavings don't affect your lungs, but they do
require special collection considerations. They may tend to clog dust
hoses and are best collected with a dustpan.
Chips
Chips are smaller than shavings and are typically generated by routers,
shapers, and planers. Electric planers can produce a lot of shavings and
require a good shop vac or collection system to run smoothly. Check your
vacuum frequently as these savings can fill up a system quickly. Sawdust
is often created at the same time as chips.
Sawdust
Sawdust in the workshop is a serious safety issue and requires proper
control. The fine dust can be difficult to control and requires special
precautions. Dust is most frequently created as a by-product to cutting
operations such as with a table or band saw or from sanding. The best way
to control sawdust is at the source, as we will discuss below.
Dust Control Strategies
Shop Ventilation
There are many dust control strategies and the most effective are
often the simplest. The hazards are increased when dust is concentrated
into an enclosed area. Because of this opening a door, window, or garage
door can have a big impact. Even more effective is to use a fan to blow
the dust out. You can also work outside for especially dusty operations.
Masks & Respirators
Dust masks and respirators are an important part of personal protection in
a workshop. Even if your working in a well-ventilated shop (or outside)
you still need to wear protection. The most common masks are the
disposable white cloth masks. These offer some level of protection, but are
porous and allow small particles to pass through. They should not be used
when working with chemicals, as they can't filter them out.
The second level of protection is a professional
respirator. This is a rubber mask that has replaceable canisters. The
canisters can be changed for different operations. Canisters for filtering
out dust particles are typically made with pleated sheets of filter
material.
Chemical filter cartridges typically have carbon in
addition to the particle filters. These are useful when working with
finishes and chemical strippers. They have a limited lifespan so please read
the directions before using.
When using a respirator it is important that it is fitted
properly to prevent air from leaking in around the edges. Read the
instructions carefully for proper fitting. As a general rule, when working
with a respirator, if you can smell the dust or chemicals, you have an air
leak.
Air Cleaners
Air cleaners (a.k.a. Air Polishers) are used to continuously filter
the air and remove small particles. They are useful for removing the very
small dust particles that escaped your dust collection systems. An air
cleaner is a good addition to an already existing system but your should
put your efforts and money first into controlling dust at the source as
well as preventing it from getting into the air in the first place. Air
cleaners are also useful for cleaning the air to an extra degree if you
are trying to achieve an ultra-fine finish.
Tool Dust Collection
As we mentioned above, you should try to control the dust at the
source, and tool-based dust collection is the best initial strategy. Many
of the tools on the market today offer dust ports and, in some cases,
built in dust bags and filters. The dust filters and bags work well but
can allow small particles to pass through. The best strategy is to use a
hose that connects to the tool's dust.
A shop vac or stationary system can then be fitted with
HEPA grade <1 micron filters. This not only helps to control dust, but
also in the case of sanding, can actually lengthen the life of your
sandpaper and make the process go faster. If you have a vacuum system we
recommend you upgrade the filter and keep it clean. In our shop, we keep
two filters on hand so that we can quickly replace the filter, wash out
the dirty one, and allow it time to dry.
Shop Vacuums
Shop vacuums are very effective at controlling dust. As mentioned above,
go ahead and upgrade your filter for the best results. Shop vacuums can be
used to suck up dust and wood chips in the shop. They can also be
connected directly to hand and stationary shop tools to collect dust. When
connected to tools they should be turned on before and after the tool is
used. When working with chip producing tools such as a planer or router
they may require frequently emptying.
Dust Collectors
Dust collection systems are ideal if you have a large workshop or do a
lot of woodworking. The stationary dust collector can be setup out of the
way and tied into all of your tools through a central collection line. The
systems allow for the use of various fittings and options such as floor
sweeps.
Single Stage Dust Collectors
Single stage dust collectors are designed to suck dust and debris into
filter bags. They are called single stage because all of the materials are
sucked through an impeller on their way to the filters. The primary
disadvantage of this, is that the impellers have to be made bigger and
stronger to withstand the impact of the debris. The larger impellers tend
to be noisier and require more power to turn.
Dual Stage Dust Collectors
In a dual stage system the debris first enters a cyclone separator
chamber where the large debris is separated from the fine dust. The fine
dust then moves on to the filter bags. Because only the dust is passing
through the impeller, it can be lighter weight. The filter bags in a dual
stage collector are designed to filter out dust (not chips like a single
stage). They are often made to <1 micron standards vs. 5 micron for a
single stage filter.
Pre-Separator
Various pre-separators are available and can be added on to a single
stage system to help remove large chips. The separators are typically a
plastic cap designed to be fitted onto a metal trashcan. The area within
the trashcan allows the large chips to "fall out" and collect at
the bottom allowing the fine dust to travel on to the dust bags. While not
as efficient as a dual stage system, a pre-separator is a great add on.
You will typically experience a static pressure loss with these systems
though.
Filter Bags
Filter bags are available in a wide range of sizes and filter ratings.
The filters are rated in microns referring to the smallest particle size
the bag can filter out. One micron or less is ideal for a shop filter.
Most systems come with bags around 5 microns.
Whole Shop Systems
Setting up a whole shop dust collection system is the ideal way to
collect and control dust from the point of origin. With a whole shop
system a main line is run with lines branching off to each piece of
equipment. Blast gates are used to control the flow from each machine. If
you're considering purchasing a dust collection system, you should design
the layout first to ensure you purchase the right size collector. See the
resources section at the end of this article for a couple of good books on
the topic of setting up a dust collection system. They cover subjects such
as pressure calculations, static pressure loss, main lines, etc.
Piping - Metal vs PVC
The piping you use in your shop is an important consideration. As
sawdust moves through the pipe at high velocities it will create a static
charge that needs to be dissipated. This prevents shocks as well as the potential for
an explosion. Properly grounded metal piping will dissipate the static
charge. PVC pipe can also be used but it must be wrapped with a grounded
bare copper wire on the inside and out. If you use any plastic fittings
(such as a blast gate) on metal piping you need to attach a copper jumper
wire to bridge the fitting and continue the ground. We offer a copper
wire grounding kit complete with the wire and fittings you need. You
can also purchase the materials from an electrical supply house.
Dust Hoses
Dust
hoses are typically made from a soft flexible plastic and are
helically wrapped to help them stay open. The dust hoses are used to
connect equipment to the piping. They also help prevent machine vibration
from traveling into the piping. You can use a longer piece of collection
hose to allow for movement of the machine. Smaller hoses can be run from
the system to hand power tools.
Dust hose are available from WoodZone in clear
and black
anti-static. The clear hoses allow you to see any clogs but need to
have a copper wire added on the inside and outside for static dissipation.
The anti-static hoses have an additive in the polymer that allows them to
conduct the static and do not require a grounding wire.
Blast Gates
Blast
gates are used to control the flow of air from the main line to the
machines. By opening a blast gate suction is allowed to occur at that
machine. You should only open one gate a time unless your system is
designed for multiple machine to be operated at the same time. (This is
typically only done in larger commercial shops.)
The blast gates are available in aluminum
and plastic.
The aluminum
gates are more durable and do not require a grounding wire. The plastic
gates are more economical but require a grounding wire to jump the
grounding around the gate.
Clamps
Various
clamps are available for dust collection systems. Wire
clamps are the most economical and are ideal for multiple connections.
Steel
band clamps work well when a more secure connection is required. Key
hose clamps are used for connections that need to be removed
frequently.
Connection Fittings 
Various fittings are available for connecting hoses together. Y-Fittings,
T-Fittings,
Splices,
Elbows,
and others are also used to layout a system. Other fittings are available
for reducing
and enlarging hoses to allow them to connect to tools and other
systems. Specialty fittings such as floor
sweeps and lathe
dust collection hoods are also available.
Resources
This article was designed to educate you on the basics of dust
collection systems, strategies, and equipment. For more details we
recommend the following books.
Controlling
Dust in the Workshop by Rick Peters
Woodshop
Dust Control Sandor Nagyszalanczy
Dust
Collection Parts are available in our online store.
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