Wood Finishes
What about the finish?
 When I'm talking to a woodworker who's been in the business
for a long time, they yell. 20-40 years around loud machinery, they
can't hear very well. They also are often missing a finger. One thing there is a lot of yelling back and forth
about, without much finger pointing, is wood finishes. There are two main categories of finishes: surface and
penetrating. Surface finishes-think bug in the ice cube-include lacquers,
varnishes and polyurethanes. They can be solvent, water or petro-chemical
based. When I pick up a conversion varnish (a specific type of varnish), they ask for everything but password
and a blood sample. Nasty stuff. If applied properly, they are durable, quick to dry and have a consistent sheen. On the other hand, if there is a scratch, which there will
be, the film needs to be sanded off and reapplied. The other problem, and the
reason these finishes are often reformulated and taken off the shelves, is that
they all toxic at some level.
By now, you have heard the term VOC, short for volatile
organic compound. VOC's are not a bad thing in itself. They are things that
evaporate. Anything you smell is a VOC, a rose, cookies baking, or your
furniture (or paint or carpets) off-gassing. The problem comes from toxic
solids and solvents, used in the finishes to increase viscosity and speed up
drying.
Penetrating finishes like tung oil (from the nut of the
chinawood tree) or linseed oil (from flax) seep into the wood, enhancing all
the unique grain patterns. Diluted with a citrus-based solvent, the positives
are that it's non-toxic, can be reapplied with less preparation, and in our
opinion, the best way to appreciate the wood. But, it takes work, lots of
applications and elbow grease. It also may need to be reapplied every few years.
It can take longer to dry and cure. These are some of the reasons the
more toxic counterparts were developed. For the DIYer, we recommend a pre-mixed version of a penetrating finish, like OSMO
or WOCA. These use natural oils, waxes and benzene-free drying agents. You may
find tung oil at the hardware store, cut with less desirable ingredients, so
read the label. Livingreen is a great resource for genuine eco-friendly
finishes. California
has the toughest regulation of finishes (and paint) to maintain higher
air-quality standards. We know a finisher who quit the business, because he
wasn't happy with the reformulations. Some businesses move operations out of
state.
As I see it, if woodworkers are already deaf and missing fingers, why
add toxic fumes to his job? Let alone to the environment or your home?
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