START TO FINISH:
THE ENDURANCE TEST
By Michael Dresdner
This
is an excerpt from an article in the May/June, 2000 issue of Woodworker's
Journal.
Picking
the "right" finish for your most recent woodworking triumph may seem like
a daunting task, given the confusing array of choices. To make the correct
choice, start out by answering three primary questions before you begin:
1. How durable does the finish need to be;
2. What kind of appearance do I want; and
3. What's the best application for me?
Durability
Durability is the first thing you should determine. Ask yourself, "what
must this finish endure?" An art turning can get by with nothing more
than a coat of oil. A kitchen table or countertop, which needs to endure
hot coffeepots, scratches, stains, and even chemicals and strong cleansers,
will require something much more durable. Patio and outdoor furniture
will need a finish that can stand up to temperature and humidity variances.
Salad bowls and cutting boards need a special "salad bowl" finish, which
is specifically made for objects which come into contact with food.
Durability
is also affected by how thickly a finish is applied. A very thin finish
regardless of the type will not protect as well as a thicker application
of the same finish.
Appearance
Staining, of course, changes the color of the wood, but clear finishes
will also alter the appearance of the wood. Most waterborne lacquers and
polyurethanes are completely clear to slightly blue-gray. They will add
almost no color to white woods such as maple, holly, and spruce. Shellac
and lacquer will add warmth and color to the wood. Oils (including Danish
Oil, Tung Oil, and oil-based poyurethanes) generally add the greatest
amount of amber tones to wood, especially when several coats are applied.
With figured
woods, such as curly or bird's eye maple, you can actually use the finish
to intensify the figure, or "pop the grain," even without staining. One
of the best "grain poppers" around is boiled linseed oil, but shellac,
lacquer, and most oil-based varnishes will also do the trick.
By adding
one or two coats of shellac to a piece of figured wood, you can achieve
a stunning effect called "chatoyance," from the French meaning "like a
cat's eye." If you've ever seen the semi-precious stone Tiger-Eye, you'll
notice that as you change your viewing angle, the light and dark bands
of color change places; this is chatoyance.
Application
Most finishes can be applied in a variety of ways. Shellac, for instance,
can be wiped on, brushed on, or sprayed on. The same is true of Danish
Oil, varnish, and most waterbornes. Some finishes, however, lend themselves
more to one application style or another, and others are formulated for
a particular application method.
Waxes and
gel finishes are specifically designed for wipe-on application. Though
nearly every varnish or polyurethane can be wiped on instead of brushed
on, some are designed for easy wiping and thin application. This will
usually be stated on the can.
Certain
lacquers and conversion varnishes are designed for spraying and will dry
too fast if applied with a brush or rag.
To help
you choose the right finish using Dresdner's "Appearance, Durability
and Application" approach, we've made a comparison guide of all our
carefully selected finishing products. See our Finishing
Comparison Guide for a complete chart of products.
Michael
Dresdner is a nationally known finishing expert and author. This article
originally appeared in Woodworker's
Journal May/June 2000 issue. For a free trial issue, visit www.woodworkersjournal.com.
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