What follows is the text of an article I wrote for the Oak, Atlantia's Arts & Sciences newsletter, giving a very basic set of directions for making a mosaic tabletop. This text-only version omits the diagrams that were supplied with the printed article.
Mosaic, the art of setting pieces of stone, glass, tile, shell, or similar
materials in decorative patterns, flourished throughout the Roman and
medieval periods and is enjoying a resurgence today. Medieval mosaics
primarily decorated architectural forms (floors, walls and ceilings). A
mosaic tabletop or serving tray, however, makes a good practice piece, as
well as a good visual aid to use when trying to persuade your room-mate,
spouse or landlord to allow you to apply mosaic designs to more permanent
parts of the house.
The "indirect" mosaic process described below, in which tesserae (mosaic
tiles) are arranged upside down on an adhesive surface and then transferred
to the table or tray, will produce a smooth, usable tabletop or tray
surface. The materials for this project may be obtained at a stained-glass
supply store or any large craft store. Items marked with an asterisk are available
at the local hardware store as well at a much lower price, so shop there
first!
Tools and Materials:
Design considerations:
Choose a design for your piece. For my first table, I used Moroccan design
elements, and re-drew them into a somewhat simpler form. The key
is not to fix on a more intricate design than you can achieve given the size
of tesserae you are willing to use. For my table, I cut the 1-inch glass
tiles I was using into quarters, and in some cases diagonally into eighths.
Cut a few tiles and experiment with placing them on top of your design
drawing, and re-draw and simplify until you are happy with the results. A design with strong linear elements and simple, clean curves will look
good in mosaic.
Drawing the cartoon:
Draw your design full-size, exactly to scale. You will work directly from
this "cartoon" in making your mosaic. When you have drawn the design, go
over the lines with permanent black marker so they are clear and
unambiguous. Now, tape the cartoon, face up, to your work surface.
Put plastic film sticky-side-up on top of the cartoon, and tape it down.
Shaping the tesserae:
Using the tile nippers or carbide wheel cutter, cut tesserae to shapes
required to form the design. Place them upside down (usually smooth side
down) on the sticky film. Space them approximately 1/10 inch apart, to make
your design visually coherent while leaving space for the grout to be worked
between the pieces. If you are working with an area of 1 foot or more
square, cutting your tiles to approximately � inches on a side (that is,
cutting a standard tile in quarters) will give you an attractive level of
detail in the finished piece.
Do the main design elements first and then set the background tesserae
around them. The two most common tiling techniques, one or both of which is
used for the background of virtually all pictorial or geometric mosaics, are
"opus tesselatum" and "opus vermiculum." Both techniques emphasize
the primary design elements - opus vermiculum by echoing the line of the
design, and opus tesselatum by rendering the background less eye-catching.
When all the tesserae are in place, roll with roll of paper towels or a
rolling pin padded with a dish towel to adhere them firmly to the adhesive
film.
Preparing the table surface:
Next, prepare the surface of the table or tray. The surface must have
enough texture to allow the adhesive to grip; unfinished plywood is fine as
is, but wood that has been finished may need to be roughed up slightly with
coarse sandpaper ("keying" the surface). After keying, make sure all dust
is removed and the surface is clean.
Using your putty knife, lay down a layer of adhesive on the table or tray.
If your tesserae are of equal thickness, this layer should be fairly thin
(like a layer of butter on bread); if the tesserae are different
thicknesses, then enough to accommodate their varied depths and still
produce a smooth surface) (Fig. 4).
Turn the sheet of plastic film, with the tesserae attached, over onto the
adhesive-coated surface of your tray or table, and smooth it with your
roller.
Now the hard part:
Now, you have moist adhesive under a layer of plastic. You can either wait
patiently for a long time, or use a razor to make small slits in the plastic
to speed the drying process. NOW WAIT until adhesive is dry enough that
slow, careful removal of the sticky plastic does not dislodge the tesserae.
Really, go on waiting. If you don't, you'll wish you had!
Finishing and grouting:
Now take the plastic off. Take tweezers, and a little dab of adhesive, and
replace the tesserae that came up with the plastic film.
Check the directions on your tile adhesive, and let it dry accordingly
before applying grout. Then use the putty knife to apply grout. Work the
grout down into the cracks between your tesserae.
When the grout has set firmly, but has not completely dried, use a damp
sponge to clean off the excess grout. After the piece has dried completely,
use a slightly damp scrungie pad and elbow grease to remove all traces of
grout from the surface of the tesserae; then polish with a cloth towel until
the tesserae shine.
Finally, after the grout is completely dry, use grout sealer or clear floor
wax to seal the surface of your piece.
References:
If you are interested in books on this topic, the glassworkers bibliography lists a number of books on mosaics. Many of them, while
concentrating on "hands-on" projects, also include pictures of Roman and
Byzantine mosaic work.