Over the years, I have collected some mosaic experience. When I was learning ceramics at the Keramik Art Studio in Hamburg, one of the two ceramic masters there was working on an unbelievable project. Four mosaics of the four seasons, depicted in mosaics. The mosaic pieces were hand made from clay and glazed in formulas which he himself developed ( I learned glaze chemistry from him), each piece less than a centimeter in diameter. I don' t have a great photo of the pieces, but here is a small one, to give you an idea:
It is very important to construct your mosaic on a stable base. Wood is not a stable base, unless it is marine multiplex and has been sealed for moisture on both sides. If you use a simple piece of wood, as soon as the moisture hits it, it is going to absorb moisture on one side and will eventually bow. When it dries it will contract. This means that the pieces of the mosaic pieces will disengage from the glue, that the grout will break.
Other stable bases include: cement, metal, plaster, stone, sealed MDF.
Here are some mosaics I have done. The table tops were done with all handmade pieces, as were the pizza oven doors, the mirror and the art collages. The floor mosic is a mixtuer of handmade pieces, purchased tile, and river stone.
You'll need to click on the collage to enlarge to see the detail.
The collage wall art tiles are mounted on sheets of pliable lead, which are then mounted on to stretched canvass, covered with rice paper, painted and waxed.
Several of these pieces were private commissions. The mosaic for the half-round console table top took over three months to make -- first I cut the clay into the pattern, and let the individual tiles dry very slowly under plastic for 4 weeks. I numbered the tiles from the back so I would know where to place them on the table -- the whole thing was like a puzzle that hd to fit exactly. Then I bisque fired the tiles, then glazed them in a midnight blue and a beige-green, then laid them in. I made doubles for about 30% of the pieces in case something went wrong. The whole table top had to be constructed at 110% of the size of the actual board, because clay shrinks 8 to 12% after it is fired. But the result was worth it.
All of the mosaic surfaces have been: sealed before application, and grout sealer is applied afterwards, to protect the grout color.
It also pays to invest in high quality ceramic cement glue and grout. I often mix pigment into the grout to get the color I want.
As with the ceramics series, I will be sure to post as I do some mosaics. For me mosaics can also be works in progress; I have several started on this property which I will finish over time, as the muse comes to visit.