Tips for Finishing Walnut

Make Sapwood Disappear

Even select walnut boards are likely to contain an
occasional streak of light-colored sapwood. Some projects
benefit from the contrast provided by skillfully
placed sapwood, but in most cases it’s merely a distraction.
If you can’t afford the luxury of avoiding all sapwood, we’ll show
you how to make it less conspicuous. Even though the initial investment
for dye, shellac and glaze materials will set you back about $100, most of these
products are highly concentrated and should last you many years.

Dyeing sapwood looks paint-by-number simple but there are a few tricks. The key
to the process is getting the dye color to match the heartwood color. Don’t
bother with dyes labeled “walnut.” Buy red, blue, yellow and black water-soluble
dye powder and custom mix a sapwood. We gradually adjusted the color of the dye by adding drops of
blue and black to reach the purplish gray hue of kiln-dried walnut.
An eye-dropper works great for this. Air-dried walnut has more
red. Adjust your dye accordingly using the Color Mixing Chart provided here as a guide.

We’re using water-soluble dye because it resists fading
in sunlight better than alcohol-soluble dye and is
easy to apply without leaving lap marks. One drawback,
however, is its tendency to raise wood grain. Minimize
grain raising by wetting the wood, letting it dry, and sanding
off the raised grain with 220-grit sandpaper before applying the dye.
Don’t sand too much or you’ll expose new
wood and negate the effect.

Here are a few more tips for working with watersoluble
dye:

– Wet the end grain before dyeing it to keep it from soaking up too
much dye.

– Start with a diluted dye; you can always increase the intensity of the
color by adding a “layer” of more concentrated dye.

– Adjust the color by adding another layer (refer to the Color Mixing
Chart). Wipe on green dye to decrease red, for example.

– The color you see when you apply the dye to the wood is close to
the color you’ll end up with. The wood will look dull when the dye dries,
but the “wet” color will return when the finish is applied.

– Lighten dyed wood by wiping off some dye with a damp rag. If you
really goof, use household chlorine bleach to remove almost all of the dye.

Allow the dyed wood to dry completely, usually overnight. Then seal
the entire surface with a thin coat of brushed on shellac (about a 2-lb.
cut of super-blonde or other dewaxed shellac). Allow the sealer to dry
and sand it lightly with 320-grit sandpaper. If you’re happy with the way
the sapwood blends after the sealer is applied you can move on to applying
the final coats of finish. To blend the dyed sapwood more completely, and add greater depth and richer color, apply a thin layer
of glaze before applying the final coats of finish.

Glaze is essentially thinned paint that’s layered over a
sealed surface. Commercially prepared glazes are available,
or you can make your own. Mix up an oil glaze by
combining artist’s oil paint (available at art supply stores)
with a glazing medium consisting of three parts boiled linseed
oil, two parts mineral spirits and 1 part Japan drier, to
the consistency of heavy cream. We chose the “burnt
umber” color and it looked great. Pick up the following colors
as a starter set for blending your own custom colors;
burnt umber, raw umber, burnt sienna, raw sienna, Vandyke
brown, yellow ochre, black and blue.

Complete the process of blending the sapwood by applying
a layer of glaze, as shown in Photo 2. Keep the brush
“dry” by removing
excess glaze from the
bristles with a rag. To
add glaze in one section,
“stipple” it on
with the tips of the
bristles and then
smooth it. If you
make a mistake,
remove the glaze
using a rag dampened
with mineral
spirits.

Allow the glaze to
dry completely, a minimum of 24 hours, before applying the
final coats of finish. Check by running your hand across the
surface. If glaze rubs off, it’s not dry.

1. Use a small artist’s paint brush to carefully
dye the sapwood, following along the grain line.
Blend the edge of the dye into the heartwood with
the corner of a damp rag. Dampen the wood before
applying the dye.

2. Apply the glaze with a rag or brush. Remove the excess,
leaving a thin layer.Then use a good-quality paint brush with
soft bristles to manipulate the glaze, adding or subtracting as
needed to blend the dyed sapwood into the heartwood.

End Grain Can Be Beautiful

End grain reveals much about a board’s history and provides
an attractive detail in many woodworking projects.
But too often the end grain soaks up so much finish that the
detail gets lost in a dark, muddy cloud of oil or stain. To
bring out the full potential of the end grain detail in your
next project, seal it with a thin coat of 1⁄2-lb. cut shellac
before you apply the stain or oil. Sand the face with 320-grit
sandpaper after you seal the end grain to remove any sealer
that may have lapped onto it. Then lightly sand the end
before you apply the oil or stain.

Matching Old Walnut

As walnut ages its color changes.
Matching the cool, charcoal-gray color
of new kiln-dried walnut to the mellow mahogany
red or amber gold of aged walnut is a challenge faced
by anyone who repairs old furniture.

In most cases the new walnut will have to be lightened
before adding color with dye. Use two-part wood bleach, available
at most hardware and paint stores. This bleach will lighten the walnut
without removing all of the reddish tones. Mix and apply the bleach according
to the instructions on the containers. Allow it to dry. Then lightly sand the
surface with 220-grit sandpaper.

Once the wood has been lightened with bleach, mix dye to match the lightest, most
prevalent color of the wood. If you’re matching reddish walnut like ours, use our aged walnut
recipe (at right) to mix the dye and then adjust the color to match your project. The process
of dyeing and glazing is the same as that for blending sapwood. We left extra glaze in the recesses around
the turnings to duplicate the aged finish on the other legs.

1. Bleach your replacement part by
mixing two-part wood bleach according
to the directions on the label and
immediately applying it to the new
walnut. Disposable sponge brushes work
well for applying bleach. Allow the bleach
to dry and lightly sand the surface.

2. Dye the bleached wood to approximate
the color of the aged walnut. Err on the
light side. Allow the dye to dry.Then
seal with a coat of 1-lb. cut shellac, allow
to dry and sand with 320-grit sandpaper

Brush or wipe a thin layer of glaze over
the dyed walnut. Remove the excess glaze
with a rag or dry brush, leaving enough to
match the color of the new piece to the
aged walnut. Let the glaze dry before
applying the final coats of finish.

Warming Up Colorless Finishes

Water-borne varnishes and lacquer are often used on
light-colored wood like maple to avoid the “yellowing”
that occurs with traditional shellac and varnish finishes.
Darker woods like walnut, on the other hand, look better
with a “warmer” finish that brings out the rich, dark color.

If you plan on using a water-borne varnish or lacquer finish,
consider warming up the walnut first with a coat of dye.
We used the aged walnut recipe diluted three parts to one.
Allow the dye to dry. Then brush on a sealer coat of a 2-lb.
cut of dewaxed shellac to keep the water-borne finish from
dissolving the dye. Dewaxed shellac makes an excellent
undercoat for most water-borne and lacquer finishes, but
check the label to be sure.

Sources

(Source information may have changed since the original publication date.)

Woodworker’s Supply, Inc.
1108 North Glenn Rd.

Casper, Wyoming 82601
800-645-9292

Woodcraft
210 Wood Cnty. Industrial Park

P.O. Box 1686

Parkersburg, WV 26102-1686
woodcraft.com
800-225-1153

Constantine’s

2050 Eastchester Rd.

Bronx, NY 10461
constantines.com
800-223-8087

Supplies

This story originally appeared in American Woodworker October 1999, Issue #75.