Four mosaic backers make up a mosaic coaster set. Pick a variety of designs and make as gifts. Be sure to use a waterproof adhesive, and to finish it out, you can paint the edges and back with acrylic paint. Then just glue on the cork on the back for a no-skid surface.
Treatment options for edges:
- you can paint the edges and back with paints that do not contain solvents of any kind as they will warp the board. Use latex or acrylic paints.
- you can thinset the edges
- you can grout the edges