Draw the mosaic design on a piece of wood the size of the intended sign. This wood will serve as the design template. Stick the chosen tiles onto the template using PVA glue and leave the glue to dry for at least four hours.
Mix water with grout powder in a container adding small amounts of water during the mixing process. The grout should be mixed until the consistency of the mixture is paste like, it should not be runny or too stiff.
Apply the grout mixture over the tiled area of the sign template making sure all the tiles are covered with grout. The grout mixture should be limited to the areas of the sign that are tiled and should not cover non-tiled areas of the sign.
Wipe excess grout from the sign using a cloth or sponge and clean water held in a container. The cloth or sponge should be kept clean throughout the removal of excess grout to ensure all excess grout is removed. The grout should be left to dry for at least two hours.
Remove any grout of glue materials from the un-tiled areas of the mosaic sign using sandpaper to allow the design to be completed.