By
Jon Eakes
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Some tools make dust,
some tools collect dust and some tools collect specific types of dust. Even
the broom has its limits - as the instruction manual for fibre cement siding
states that you should never dry sweep their dust! You don't want that silica
up in the air.
So let's start this month with a quick look at shop-vacs. For some of you,
the shop-vac is used as a clean-up tool after making all the mess. For others,
the shop-vac is used to collect the dust while it is being made, a tactic
that addresses some questions of worksite health and safety.
Dust Collection Interceptors
Workshops are often equipped
with built-in dust collection, piped all over the shop. A variant of that for
on-site work is attaching the shop-vac to the tools. But shop-vacs fill up quickly,
or may not be equipped to properly filter what is being sent through them. There
are two specialized intercept devices that can be very useful.
The Veritas Cyclone Lids
(www.LeeValley Tools.com)
are just lids that sit on top of garbage cans with a hose out the top going
to any shop-vac and the other hose going to a tool that makes chips, shavings
or lots of dust - this system works best with heavier materials like wood
chips.
The angles of the two hoses create a cyclone effect inside the can which causes
heavy materials to drop to the bottom while only a little dust moves on to
the shop-vac. The fantastic deal with this is that wood shavings collect directly
in the garbage can and you have far less clogging of the shop-vac itself.
It will even work to collect water. The finer the dust being collected, the
less effective will be the action of settling to the bottom.
Drywall dust is a special problem because it is so light and yet so abrasive.
It will instantly kill most domestic vacuum cleaners, simply grinding their
motors to death and blows right out past the filters of inexpensive shop-vacs
and back onto the walls.
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Shop-vacs
If we look at the shop-vac itself, there are two basic types, and then a variety
of filters.
Most shop-vacs place the motor right in the air stream, using the dust collecting
air to cool the motor. The other type uses one motor but two fans, one to
cool the motor and the other to collect dust - often called a by-pass motor.
As you can imagine the by-pass system costs more to build, but usually lasts
longer and often runs quieter.
Shop-vacs will usually have two or more filters. There is always a bit of
a filter right before the air gets into the motor. This filter is often forgotten
because it is built into the motor housing. If you have never cleaned or replaced
it, you probably don't have a lot of suction on that machine and you may be
overheating the motor.
There is usually a filter just above the bucket and you may or may not use
filtered collection bags. The advantage of using a bag is that it keeps the
other filters cleaner longer - there is less mess to empty the bucket but
it costs considerably more than just filling the bucket.
The Porter-Cable
drywall vac has a special washable, automotive type of filter specifically designed
to work well with drywall dust. In fact, it has a shaker attachment that will
cause accumulated drywall dust on the filter to fall to the bottom of the bucket.
This is exceptionally effective with drywall dust, but it clogs quickly with
wood dust because the wood dust doesn't fall off. So in this machine a collection
bag should be used when picking up fine saw dust but no collection bag when
picking up drywall dust.
In fact, many machines,
like the Fein Turbo II Dust Extractor provide a variety of filters from 5 micron
to 1 micron or 0.3 micron HEPA filters. Why such a variety? Because of cases
like the James Hardie instruction manual that specifies if you are cutting fibre-cement
siding indoors, you must use a HEPA dust collection device. Match your use of
filters to what you are collecting. Don't waste a HEPA filter on ordinary sawdust
and don't use an ordinary filter with hazardous materials.
Powerful portable shop-vacs with good enough filtration to avoid blowing the
dust right out the other side can be your secret public relations program when
working in an occupied dwelling. Use a floor sweeping head to slide up the wall
below a drill or a cut saw and you don't have to try and clean up the rug. Make
sure all tools have vac hose attachments and use them. Choose a vac that is
trigger actuated - your tool plugs into the vac and when you turn on the tool,
the vac goes on automatically, going off a few seconds after you turn the tool
off. Make noise one of the criteria in purchasing a shop-vac, with the Fein
by-pass motor probably setting the benchmark for least noise.
I recently had the chance
to take on one of the messiest jobs in a dust free manner thanks to a well thought
out tool from Fein, the Construction
Cutter. Basically an overgrown biscuit cutter with a diamond blade, it slices
cleanly into wall tiles, cement board, gypsum, plaster - just about anything
except wood. Having the blade caged in so well allows for total trapping of
the dust and evacuation through the shop-vac hose attachment. Notice as well
that it allows for almost flush cutting of these materials without danger of
scratching anything near-by or loosening tile or grout. A depth stop on the
plunge allows you to protect or cut through substrate.
Have you ever dumped a bag of plaster, mortar or concrete into a bucket and
stood there wishing the dust cloud would go away while you were mixing it? Simply
plunge a shop-vac hose halfway down to the surface and the enclosed space will
cause all that dust to immediately collect in that restricted air flow and disappear,
long before it rises to get your lungs. HB
Montreal-based TV broadcaster, author, home renovation and tool expert
Jon Eakes provides a tool feature in each edition of Home BUILDER.
www.JonEakes.com
