On Making Intarsias"
By Meredith Jones
Kitsap Mineral and Gem Society
Sheep"is the title ofthis beautiful intarsia by Meredith Jones... All
of the material is petrified wood except the brown jasper behind the black
cliff and the polka dot agate used for the eyes. It took about 250 hours
to make and fit all the pieces, including 22 tiny pieces that make up each
After the picture is completely assembled the next
step is bonding it to a sheet of ¾ inch plywood. Choose a good flat
piece that isn't warped or twisted. Completely coat all sides of the wood
with polyester resin (plastic) to seal out moisture. If left unsealed, dampness
in the atmosphere can cause plywood to warp, which could ruin your intarsia.
A liberal coat of polyester resin can also be used to secure the picture
to the plywood. If the back surface of your picture is quite irregular,
you may apply a oat of resin to level it off before bonding to the plywood.
If a picture frame of petrified wood or other material
is also desired, the plywood should be cut large enough to extend approximately
two inches beyond each side of your intarsia for support.
The intarsia should be lapped and polished before adding
the frame. The frame sections, being raised, should be polished separately
and added piece by piece. See Fig. 4.
A great deal could be written about various lapping
methods. Small objects up to 12 or 15 inches can be worked on most any type
of lap but as the size increases, problems multiply.
I like vibrating laps for small objects because they
require very little attention and do a good job. I once tried to lap a 22-inch
intarsia on a 24-inch vibrating lap but found the wear in the plate had
rendered it useless. This same lap did good work on objects half as large.
The old rotary cast iron laps will do a good job on
any size project if set up and operated properly. Aluminum or plate glass
are some of the other materials that can be substituted for the more costly
Now let's consider lapping a large intarsia or a tabletop
on a fifteen or twenty inch diameter lap. The fist question is how to get
grit and water under the large object and onto the smaller lap. Next, how
large a tub will be needed to contain flying waste material and also allow
proper maneuvering of the large object?
My answer to these problems is simply turn the whole
operation upside down. All large objects can be placed on a turntable and
revolved. In this position they take the place of the lap plate. The grit
and water is easily applied to the face-up work and the tub need only be
large enough to contain and swing the object.
Each winter I make one intarsia, approximately 18x24
inches in overall size. Large round log sections and flat specimens that
I have saved during the past year are now lapped on the face of the new
intarsia. The grit does double duty by finishing both the intarsia and these
other pieces at the same time. You get twice as much lapping done in the
same amount of time without any wear on a costly lap plate.