The Gaff Rig recognizes that boat building involves inherently
dangerous activities, and each builder must be responsible for his own safety. The Gaff
Rig encourages all builders to read manufacturer’s instructions, follow all safety
precautions, and be pro-active in seeking out more information on reducing the risk of
injury or illness. Information presented here is general in nature and not intended to
replace the safety instructions provided with products or tools.
We tend to think the most dangerous things in our boat
building shops as those whirring blades of metal that would rip us apart just as easily as
they tear through wood. Yet we know more insidious dangers lie in the more mundane things
such as chemical exposure, lung and eye irritants, etc.
Most of us use "typical" safety measures such as latex
gloves to prevent accidental contact with chemicals, and dust masks to prevent breathing
in sawdust. That dust mask is fine for some tasks, but the truth may be that wood dust,
from sanding and sawing, may be the most hazardous thing we are exposed to because we
don’t give it the respect it deserves. Exposure to chemical vapors pose another
hazard, because they go straight through that dust mask without hesitation.
How much exposure is safe? OHSA, the US Occupational Health and
Safety Administration, publishes two kinds of "allowable exposure" ratings. One
rating is for continuous exposure over an eight hour period, which I’ll call the
workplace rating. The other is a "short term" exposure rating. For wood dust,
OHSA set the workplace exposure limit at 5 milligrams per square meter, and for short term
exposure, 10 milligrams per square meter. How much wood dust is that? For a 20 x 20 foot
shop with a 10 foot ceiling, a single teaspoon of wood dust would exceed 10 milligrams per
square meter.
Before you give up sanding forever, as tempting as that is,
realize that teaspoon would have to be evenly distributed in the air in the shop, and that
rarely happens. Larger wood particles fall to the floor immediately, and even smaller ones
tend to fall out after a brief period. Our intermittent use of tools, which are off when
we are in the "moaning chair" with our favorite adult beverage, helps us
(remember that next time your significant other asks why you are sitting there staring at
the boat.) Still, our proximity to the tool means we are probably exposed to far greater
concentrations than a simple teaspoon for short periods of time. Its something to think
about next time you’re tempted to lean in close to the belt sander to see through the
cloud of dust.
Many of us have seen the professional dust collection systems to
capture sawdust at its source in large shops. But buying that kind of equipment for our
home shops, especially if the shop is new and geared to building just this single boat, is
out of reach for most of us. Still, there are easy solutions to the problem that
don’t cost a fortune.
Home systems, that hook up to a single machine, can be purchased
for less than $200. Dust collection systems are rated according to cubic feet per minute
(cfm) of air they move. If you are considering purchasing a system, keep in mind that most
home shop tools need at least a 350 cfm unit (that’s good for a 10" table saw,
14" band saw, 6" jointer, 12" disc sander, 16" drill press and an
oscillating spindle sander.) Radial arm saws vary, from 350 to 500 cfm, depending on
brand. And larger woodworking machines need more dust collection power. The manufacturers
of the tools will be able to provide a recommendation for their specific tool. The dust
bags used on these systems don’t trap the finest, and most dangerous particles, so
most manufacturers still recommend you utilize a shop filter and/or a good cartridge
respirator.
There’s an even better solution than a dust collector, shop
filter and cartridge respirator: ventilation. 
In nice weather, opening all the doors and windows can go a
long way to reduce our exposure. Still, clouds of wood dust can billow up right around us
if the air is relatively still. The common box-style fan which most of us already own can
help us with "assisted ventilation." I prefer to place the fan behind me in a
door or window opening, blowing the dust away from me as I work, and providing me with a
stream of fresh air. In enclosed areas, such as the cabin of our boats, I prefer to have
the box fan blowing air out of the front hatch, bringing fresh air into the cabin (and I
try to remember to work with the sander between me and the fan.)
During cold weather, having the doors open and a fan blowing
might not be possible. Although not quite as effective as dust collection systems and
filters, shop filtration systems by themselves can cut down on airborne wood dust at a
fairly economical cost.
The commercial units
still take up valuable boat-building dollars. An alternative is our common box fan again,
with a furnace filter in front of it. This low-tech solution can be made pretty efficient
with the new allergy filters that trap smaller particulate matter. Some shops build
elaborate boxes to house the fan and hold the filter, but the fan can easily hold the
filter in place once it is turned on. Simple, low cost, and it works.
Filtration works with most wood dust, but isn’t much help
with chemical exposure. And even with wood dust, without plenty of ventilation, you could
still have that teaspoon of fine wood dust floating in the air. A good cartridge
respirator is needed.
Nearly every home improvement chain store sells cartridge
respirators at an economical price in the paint department. They are adequate for most
chemicals we come in contact with. I use a respirator with a "hepa" style filter
adequate for working with refractory materials (it filters out very small particles.) But,
because of my beard, it doesn’t seal well against my face, and I make sure
there’s plenty of ventilation as well. That means I simply can’t do some tasks
when its really cold outside, or I have to brave the cold.
In the hierarchy of methods to control exposure, most experts put
ventilation as the best approach, combined with or followed by use of a good cartridge
respirator. The most expensive solutions, filtration and dust collection actually fall in
third place, and usually still require the use of a respirator.
