Art of Intarsia"
by William Grundke
and Framing Your Intarsia
the past five installments of this series, we have presented the steps for
completing an intarsia picture, starting with the selection of gem materials
and taking the operation through the final surface finishing. When all this
is done, it is time to prepare the intarsia for display.
project in the March 1982 issue was the making of a small gemstone picture
to be set into the top of a jewelry box. An opening was cut into the top
of the box to accommodate the intarsia and it was cemented in place. The
addition of a wood backing piece to support the stonework completed the
mounting of the picture.
If you wish to display the intarsia as you would a painting, putting it
in a frame is an effective means. The way in which this writer frames such
a work is shown in Fig. 32, which happens to be Silent Night, the
cover subject of the December 1981 issue of this magazine. The intarsia
is mounted on a velvet-covered backing piece which is fitted into a picture
first step is to put a 5/16" wide brass edging around the intarsia
as described in Part Five of this series (G&M, April 1982). This,
in effect, is an inner frame.
attach the intarsia to the backing board, I use flat head bolts (machine
screws), 1/8" in diameter and 5/8" long, with hex nuts. On each
bolt, one edge of the head is ground flat to prevent it from turning in
the adhesive with which it is attached to the intarsia.
use plastic steel epoxy for the adhesive, but regular epoxy or epoxy putty
would also be satisfactory. The flat heads of the bolts are attached to
the corners on the back of the intarsia with "globs" of plastic
steel. Small amounts of the adhesive are built up over the heads to insure
a strong bond. Figure 33 shows the back of Silent Night with the
bolts in place. Figure 33A is a closeup of one of the bolts and the surrounding
the adhesive has set, a piece of paper is laid on the floor and the intarsia
is set on it with the bolts projecting downward. The bolts are pushed through
the paper, then a pencil line is made around the brass frame. This outline
is transferred to a piece of ¼" masonite, and the bolt locations
are marked through the holes in the paper. Holes for the bolts are drilled
through the masonite at these spots. Depending on the individual intarsia,
it may be necessary to countersink these holes to accommodate the bolt heads
and adhesive. This was not necessary on Silent Night because the
brass rim projects down far enough from the intarsia back that its edge
is below the level of the adhesive and bolt heads.
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area of the desired width for a border around the intarsia (refer to Fig.
32) is marked out. The masonite is sawed to size along this outline.
backing board is then covered with velvet. I select a piece of velvet of
a color that will compliment the intarsia and cut a piece that extends ½"
from all sides of the masonite. To attach the velvet to the backing board
I use 3M Spray Adhesive. Coatings of this adhesive are sprayed on the back
of the velvet and on the smooth face of the masonite, then allowed to dry.
The velvet is attached by laying it down on the masonite, starting at a
lower corner and working upward and outward. Use a wide soft-bristled paint
brush of a soft cloth to smooth it out. This operation is a little tricky
because when the dried adhesive o the velvet meets that on the masonite,
here is an instant bond; it works like contact cement. Work carefully to
avoid wrinkles. The excess velvet around the edges is cut off with a sharp
knife. The bolt holes are cut through the velvet.
masonite is then put in a frame, just like you would with a picture.i use
custom-made frames to achieve a good appearance. For hangin the picture
I use the conventional combination of screw eyes and picture wire. I do
not believe that the hook arrangements seen on some frames are strong enough
for the weight involved here.
the bolts on the intarsia are pushed through the holes in masonite and the
machine nuts are threaded on to hold the assembly firmly together. Figure
34 shows the masonite backing with velvet facing within the picture frame.
The intarsia has been removed) its outline in the velvet is visible) so
that the bolt holes can be observed. Figure 35 is a back view showing the
rough side of the masonite, the nails holding it is place and the bolt holes.
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author has found the above backing method to be highly satisfactory. The
purposes of backing are to give strength and to prevent warping. Using the
cementing methods described in Part Three (G&M,Feb. 1982), including
an intarsia press, if needed, and attaching the intarsia to a backing board
work will fulfill these purposes.
are other backing methods, some of which have been used for many years.
First, let us look art a modern technique. A thin, lightweight backing may
be made with epoxy resin. Polyester resin (casting resin, etc.) is not satisfactory
because it tends to shrink which will warp the intarsia. Epoxy resin had
less shrinkage. Either glass cloth or fiberglass matting should be used
as a filler.
method for applying the epoxy resin also provides an integral frame. The
body of the intarsia picture is made of thinner gemstone slabs - 3/16"
for instance. Slabs making up the border are cut 3/8" thick. (Or, if
you prefer to use ¼" thick slab as this writer often does, the
border could be done with stones 7/16" thick, of maybe even ½".)
When the units are cemented together face down, there is a depressed area
o the back. This area is filled with the filler (matting) and epoxy resin.
The border pieces then form a natural frame.
techniques that follow also provide strong backings that will prevent warpage.
They are traditional methods that have been used by many artisans, including
those in Italy where intarisas have been made for centuries. However, they
all have one disadvantage; they add considerable weight.
method is to make a backing of stone. IF the back of the intarsia is relatively
even, it could be lapped smooth. However, if slabs of different thickness
have been used, as is often the case, it is better to fill the resulting
depressions with cement, plaster of Paris or epoxy resin (see Fig. 36).
After filling, lap the back until it is flat.
gemstone slab large enough to cover the back may be difficult to find. If
so, two slabs may be used. Or, you might use stone other than gem material,
such as a slice of sandstone which can be purchased at a building supply
outlet. Be sure that the backing stone(s) is flat, lapping if necessary.
Cover its entire surface with mixed epoxy, then press the backing firmly
to the back of the intarsia and let set until the epoxy hardens.
clean edges all around, you can cut a backing piece that is large than the
intarsia. After it has been epoxied to the intarsia, it can be sawed to
match the front.
variation, when using a stone backing, is to cut the backing to full dimensions
for the finished picture. An intarsia of the image only - no background
- is then made and attached to the backing. A polished gemstone intarsia
against an unpolished material, such as a piece of sandstone, can provide
an interesting contrast.
other traditional method is to make a backing of plaster of Paris or Portland
cement. The intarsia is placed face down on a piece of glass and a frame
of light sheet aluminum or other sheet metal is formed around it. The metal
rim should be high enough to allow the finished product to be from ½"
to ¾" thick. Another type of frame, made with strips of wood
nailed to a wooden base, is depicted in Fig. 37. As an alternate, you can
make a frame of brass or heavier gauge aluminum to be left on as a permanent
decorative that will also reinforce the edges.
extra strength you may also place a piece of ¼" mesh galvanized
wire screen on the back of the intarsia before pouring the backing.
you wish to use plaster of Paris (available at hardware stores, lumber yards,
etc.), mix it with water according to the manufacturer's instructions. Apply
a thick coat to the back of the intarsia (inside the frame as described
above) with a paint brush. Allow to dry, then repeat the process day by
day until the desired thickness is reached. This technique minimizes the
shrinkage of the plaster to prevent warpage.
cement can be purchased at building supply house, lumber yards, etc. Mix
it half and half with fine, clean, salt-free sand. First, however, mix a
small amount of pure cement and water to a consistency of cream. Pour this
mixture over the back of the intarsia until it is barely covered, then pour
in the cement and sand mixture to a depth that will make the total thickness
of stone and cement not more than ¾". It takes approximately
21 days for the cement to cure, and it should be kept most with a wet cloth
so that it will not dry too quickly. Otherwise, it chalks and cracks.
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you wish to use a picture frame, instead of mounting the intarsia to a velvet
covered backing, as the author does, you can simply use a frame that fits
the intarsia. In that case, the stonework must be thin enough to coincide
with the depth of the rabbet in the frame. Or, you can use a custom-made
frame which allows for a deeper rabbet.
another method preferred by some artisans is to frame intrasias with cloth
matting. A visit to an art gallery or an interior decorator's would probably
turn up even more ideas.
conclude our discussion of intarsia pictures, the next installment will
cover some special techniques. Following it will be instructions for making