Faux Tortoise Shell Finish:
Tortoise shell (French Ivory to some) is a finish that became very
popular during the mid to late 1800's. It was common to see tortoise
shell on a number of different household articles including the full
half columns of shelf clocks of the period. In the 150 or more years
since these clocks were manufactured, the finish, including the
tortoise shell, has usually experienced a significant amount of
wear, tear and damage. Learning to repair, restore or recreate this
finish can do much to improve the overall quality of your
Faux tortoise shell is a beautiful, multi-colored finish where
complex shapes fade softly from one to another in random or
distinctly directional patterns. Surprisingly, creating or restoring
this sophisticated finish is not particularly difficult. That being
said, it must be noted that the techniques for producing high
quality tortoise shell with the translucence and warmth of the
original is not obvious and requires a bit of faith and foresight
throughout the process.
The presentation that follows is taken
from the book Extreme Restoration. This technique has been
used successfully in a number of clock restoration projects. They
have also been posted as a “How-to” presentation on the NAWCC web
Faux tortoise shell does not require a large investment in tools or
supplies but it is important to gather up the needed materials and
get organized before starting a project. The following basic
supplies are recommended:
Faux finishes are created using "glazes" which are nothing more
than paints that have been thinned to the point of translucence.
Artist's acrylic paints work well for this type of work. Shades such
as raw umber, burnt umber, raw sienna, burnt sienna, yellow ochre
and black pretty well cover all the wood tones needed.
Acrylics are available from art supply stores and crafts shops such
A product called “acrylic medium” or “polymer medium” is used along
with water to thin the paints and produce the translucent glazes.
One of the nice benefits of using acrylic based glazes is that they
are water soluble until completely dry making clean up quick and
General purpose artist's brushes work well. A selection of round and
flat, soft and firm should be on hand to try. A one-inch throw-away
type paint brush has relatively firm bristles and works well for
creating the grain effect.
There are no special tools needed to create professional quality
faux tortoise shell.
Basic shop materials such as #400 and #600 sand paper and #0000
steel wool will be needed. A primer/sealer such as alkyd enamel in a
flat, off-white shade will be needed for sealing the base wood
surface. Also, shellac will be needed to provide the final
A round wood dowel with a diameter of 1 ¼ to 1 ½ inch works well for
practice, developing technique and building confidence before
tackling a restoration job.
Before beginning to create or restore a tortoise shell column, it is
important to determine the appropriate design for the clock being
restored. Over the years, a number of different designs were
developed and used by different clock manufacturers.
Some tortoise shell columns will show a very distinct directional
pattern where the shades appear to swirl left to right and upward
around the column somewhat like a barber pole.
The design on other columns will show essentially no directionality
and be more a collection of multi-shaded splotches that fade
smoothly from one to another much like the shell of a live tortoise.
The range of colors can also vary greatly from one clock to another.
Some are light to medium shades of tan while others can be very dark
brown to black.
Photos of the desired pattern will be needed for a visual reference
when painting the faux grain. This is actually more important than
you may think. Search through photographs of clock cases and other
sources until you find some clear examples of the shell pattern you wish to duplicate.
Digital photos can be taken and enlarged to full size to provide a
very good reference. When using photos, make sure the colors are
accurate. Compare the photos to the actual pieces to confirm color
To produce a smooth, professional finish, it is necessary to begin
with a smooth base surface.
If the columns (or dowel) being finished raw wood, a sealer such as
alkyd enamel should be applied and allowed to fully cure. Once
cured, it sands very easily to provide a nice work surface.
If restoring columns, it is likely that they were originally sealed
with gesso. Gesso is a plaster-like material commonly used to seal
wood surfaces and provide an extremely smooth surface for faux
finishing or gilding. If the columns have gesso, it must be smoothed
and (where necessary) repaired. That is outside the scope of this
presentation, but is covered in detail in my book Extreme
In order to create a tortoise shell finish that has the soft,
translucent look of good quality originals, a highly reflective base
paint is applied to the primed and sanded columns. A bright, gloss
yellow works exceptionally well for this.
I have used a number of different types of paint including gloss
enamel from an aerosol can and acrylic enamel custom mixed to the
shade desired. A base paint that is bright and reflective is the key
to a finish that appears to almost glow.
Once the base coat has been applied and allowed to fully dry,
inspect it carefully for runs or imperfections. Number 400 grit
wet/dry sandpaper is used to very lightly sand the paint and remove
any obvious brush strokes. Don’t worry if the yellow becomes thin
and slightly translucent in some areas. This will actually add to
the layered effect.
The colors most commonly seen in faux tortoise shell are
combinations of yellow ocher, burnt umber, raw umber, raw sienna and
To begin the pattern an initial glaze of yellow ocher is mixed. A
common recipe is:
- One tablespoon of acrylic medium.
- Two tablespoons of water.
- Add ½ to 1 teaspoon of Yellow Ocher.
Mix the ingredients well. The finished mixture will be a thin,
watery and translucent. It will thicken quickly as it is applied to
The glaze can be applied in a pattern as shown or it can be brushed
on evenly. It depends on the final look desired.
Notice in the photo that the translucent yellow ocher as applied
here creates a rather "blotchy" look. This is pretty close to what
is needed for a typical tortoise shell pattern.
If the pattern being copied is noticeably directional it will
usually be a diagonal flow around the column. When this is the case,
apply the glaze with brush strokes that create this directional
Allow this first glaze set up for about an hour before second glaze
In most tortoise shell finishes, several glazes of different colors
will be applied around and over one another to build up successive
layers of “scales”. The colors are selected based on study of the
sample photos. For this sample column, Raw Umber, Burnt Umber and
Black will be applied to create the pattern. Burnt umber is the
darker of the two browns used and will be applied first.
The recipe for this glaze is the same as for
the base glaze (one part acrylic medium to two parts water). Add
enough of paint to the mixture to produce an almost opaque finish
Study the sample photos gathered previously to get a feel for the
size, shape and color of the tortoise shell you wish to create. If
the “scales” are relatively large, then a larger brush should be
used. If sharp-edged, use a flat tipped brush. Alternatively,
smaller or more rounded brushes are used as dictated by the pattern.
Load the brush with the glaze. The glaze is very thin, so do not
take a great deal of glaze on the brush or it may run. Usually, the
glaze is applied with more of a jabbing movement than a true stroke.
The resulting color will be irregular in shape and density.
Continue adding "scales" of different shape and different size. Some
scales may actually touch or overlap while others may have a good
bit of distance between them. It depends on the overall pattern you
are trying to achieve.
This first set of “scales” will set the overall shape and direction
of your pattern. If the pattern you are doing is directional, then
try to create scales that flow in the direction you see in your
sample photos. Do not place scales too closely together since
additional scales will be added using different colored glazes.
Caution #1: Don't expect things to be too attractive at this point.
Remember this is only the first layer of several that will be added.
Allow this layer of “scales” to set up for about an hour then begin
the next layer.
The next layer is created using the lighter brown (raw umber)
acrylic. The recipe is the same.
This layer of
scales will go between as well as overlapping existing scales. When
applying this glaze it will be more difficult to see the pattern you
are creating. By applying the glaze thick in some areas and thin in
others the pattern is somewhat easier to see.
Caution #2: At this point the column and paint will begin
to look pretty lumpy. Don't worry. This is all part of
building up layers of different colors. Things will change a lot in
The final layer of scales will be black. Black is used sparingly as
A smaller brush should be used and the highlights placed randomly,
but in a flow that matches the general flow of the existing scales.
These should be softened slightly by allowing the paint to thicken
for a few minutes then brush out the edges with the soft brush. At
this point the column will be quite unattractive.
Set it aside to dry for at lease 24 hours so the acrylic paints
fully cure and harden (important).
To bring out the true tortoise shell pattern it is necessary to
carefully remove portions of the previously applied glazes to create
thin translucent areas that transition smoothly from one shade to
another. This is accomplished by carefully sanding the columns with
#400 and #600 wet/dry sandpaper.
Begin by wetting a one-inch square of the #400 sandpaper then gently
sand the along the length of the column (bottom to top). This will
remove the major “lumps” and begin to lighten the overall finish.
Work slowly and step back often to get a feel for how the effect
looks. It will take very little sanding and pressure to produce
noticeable results. Over aggressive sanding will quickly cut
through to the base yellow so sand gently.
Once the major lumps are removed, carefully work from the top of the
column to the bottom making small circular motions. This will
remove varying amounts of glaze at different points and you will
begin to see the tortoise shell emerge. Pay particular attention to
the areas where you placed black highlights as these usually require
When sanding, consult your reference photo often. Many tortoise
shell clock columns appear to transition to a very dark shade near
the upper and lower ends. This may be a result of age and wax build
up or may have just been part of the production process. If you wish
to duplicate this effect, simple reduce the amount of sanding as you
approach the last inch or so of the column.
As the pattern begins to appear switch to number 600 sandpaper to
reduce the speed of cut. This will give you more control on the
overall look. This is the example columns after completing the
sanding. The pattern flows from dark to light very evenly and the
overlapping layers can be seen. The bright yellow base coat is the
key to creating the deep translucent look. As the browns are thinned
light is reflected from the bright yellow through the browns to
create the soft, warm look to the shell.
Note: As you progress with sanding it is possible that you may sand
all the way through to the bright-yellow base as shown in the small
spot above. Don’t worry, there is still more finishing to do.
A final top glaze is usually added once the sanding is completed to
your satisfaction. This final glaze is very important. It adds
another layer of depth and softens the patterns created by the
The glaze is
made with either yellow ocher or burnt umber. If you want to bring
out the lighter “yellow” tones then yellow ocher is usually better.
For a darker overall look and to “tone down” some of the lighter
areas the burnt umber works well.
The recipe for the top glaze is slightly different from other
One teaspoon of acrylic medium
- Three teaspoons of water
- ½ to 1 teaspoon of color
The top glaze is
brushed on using long strokes along the full length of the column.
Allow the top glaze to dry for an hour or more then examine it. If
the overall shade is too light, another coat of glaze can be added.
Once the shade is dark enough, set the column aside for dry
thoroughly (24 hours) or more.
Examine the cured column for runs or roughness. #600 sand paper can
be used to very gently remove any flaws or to lighten the overall
Once satisfied with the shade and pattern of the tortoise shell, it
should be protected by applying several coats of shellac.
Shellac can be applied by brushing or using a shellac “rubber”. This
will add even more depth to the finish and provide long term
protection to the faux finish.
Once the shellac is thoroughly dry and cured, it can be polished to
a high luster using a shellac rubber along with denatured alcohol
and olive oil (as a lubricant). Alternatively, #0000 steel wool can
be used to gently polish the shellac to a soft fine-furniture
The top and bottom caps of tortoise shell columns are usually
The gilding must be sealed with
clear to prevent oxidation and dulling.
Tortoise shell is one of the most attractive finishes ever applied
to antique clocks. The great variation in shades and patterns
provided almost endless variety to the basic design. As has been
demonstrated, creating authentic faux tortoise shell columns is not
overly complex and is actually quite forgiving as long as a clear
idea of the desired final finish is understood. Learning to create
or repair this antique finish will help to improve the quality of
your case refinishing and clock restorations. Find an old worn
column or even a wooden dowel and give it a try. You will be
surprised at how talented you are.
finishes were far more common on mass produced American clocks from
the 1800’s than most people realize. In addition to tortoise shell,
faux wood grain was frequently used on the sides of clock cases as a
cost effective alternative to expensive imported veneers. Gilding or
gold-leaf represents yet another decorative finish used extensively
on clocks of this period. These as well as other finishing and
restoration techniques are the central focus of the e-book Extreme