| For dramatic
results, it's hard to beat the finishing process. With
the first touch of a rag or brush, your furniture piece
comes alive and the true character of its wood grain
jumps out at you. Gone is the well-sanded but relatively
neutral surface of the raw stock. And if you have any
doubts about whether all the work was worth it, those
will probably disappear, too.
The first step in the process is to pick a suitable
finish. Many products are available with varying
characteristics. But the one thing they all have in
common is protection. All are designed to inhibit the
transfer of moisture and to prevent the surface from
being contaminated by dirt and stains.
The most common finishes are shellac, lacquer,
varnish and oil. All are solvent- or oil-based products
and therefore require some precautions. Wear protective
gloves, goggles and a respirator with organic vapor
cartridges when using these materials. And make sure
your work area is ventilated according to the
recommendations printed on the product's container.
One of the biggest differences among these four
traditional finishes is how they function on wood.
Shellac, lacquer and varnish are all surface finishes.
This means that they do not penetrate, to any great
extent, past the surface of the wood. The first coat
certainly goes in the farthest, but subsequent coats
merely build on the first to form a smooth, usually
glossy, surface. Oil, on the other hand, is considered a
penetrating finish because it reaches much deeper into
the wood and leaves only a microscopic layer of finish
on the surface. Subsequent coats continue to penetrate.
All these finishes have their strengths and
weaknesses. Shellac, for instance, is a wonderful
product. When properly applied it creates a stunning
high-gloss surface which over time takes on a remarkable
amber color. It's also very fast-drying, which is a
great advantage over some other finishes. Unfortunately,
shellac is very prone to water stains.
Lacquer is also quick-drying and is the preferred
finish of many professionals. It's usually sprayed on
and yields a clear, hard finish that stands up well to
practically any abuse. It is, however, very flammable.
Varnishes, both the traditional types and the newer
polyurethane versions, are extremely durable and some
impart a warm amber tone, not unlike shellac.
Unfortunately, varnish can be difficult to apply and it
takes a very long time to dry. Because of this, airborne
shop dust becomes a real problem. It settles in the
finish before the finish is dry. Then it has to be
rubbed out before another coat is applied.
For the beginner, an oil finish is the best choice.
It's easy to apply, dries fairly quickly and is not
difficult to repair. It also imparts silkiness to the
surface and develops a beautiful patina over time.
Preparation
Of course, proper surface preparation is one of the
keys to good finishing. And the only way to get it is by
sanding. For the best results, you should work through a
sequence of abrasives, starting at 120-grit and moving
to 150-, then to 180- and 220-grit, finishing up with
320-grit. (This process is described in more detail in
"Abrasives") Always dust off the piece thoroughly before
moving to each new grit and ease any sharp edges by hand
sanding (Photo 1). Once you're done sanding be
sure to wipe off the entire piece with a tack cloth
(Photo 2) or a rag that's been slightly dampened
with linseed oil.
Staining
If you want to alter the natural color of a piece,
you must stain or dye the wood. Oil-based stains are
certainly the most common approach. These products are
available at paint and hardware stores, and at home
centers. They contain a pigment that is suspended in an
oil and mineral spirits solution. Oil stains don't
penetrate the wood deeply. They give color by embedding
opaque pigment in the surface grain. You apply these
stains with a rag or brush, let them sit for 10 to 15
minutes, and then wipe them off.
Aniline dyes are another approach to coloring wood.
The type that is dissolved in water is the safest and
easiest to use, as well as being the most colorfast.
These dyes penetrate much more deeply than stains and
actually change the color of the wood. It's easy to
intermix colors and you can change the concentration of
color simply by adding more water.
Once you've chosen your coloring method, be sure to
test it out on some scrap pieces of stock before turning
to your project. Taking the time to get it right is much
easier than removing a stain or dye that you don't like.
Applying The Finish
When you're ready to apply your oil finish, be sure
to read the manufacturer's instructions carefully, and
do what's recommended. While specific directions may
vary, there are some general guidelines for applying an
oil finish.
Begin by rubbing a liberal amount of oil into the
surface of the wood using a lint-free rag (Photo
3). Allow the oil to absorb for about an hour, then
wipe off the excess. Let the surface dry for 24 hours,
and then rub the whole piece with No. 0000 steel wool
(Photo 4). Remove any dust, then apply another
coat of oil as before. For a good finish, you should
apply a minimum of three coats. Once the last coat is
dry and rubbed with steel wool, apply a light coat of
paste wax to the entire surface (Photo 5). When
the wax takes on a dull appearance, buff the surface to
a satin sheen with a clean, dry cloth (Photo 6). |