How to Cast Grout

Prepare your grout, following the instructions provided by the manufacturer. If no instructions are made available, pour the grout powder into a bowl or bucket and mix in small amounts of water until the powder forms a thick paste. If too much water is added, the paste cannot thicken unless more grout is added to the mixture, so be careful not to add too much water at a time.

Spray around the inside of the mold with a mold-release agent, to evenly coat the mold and prevent the grout sticking to the surface when it sets. Turn the mold in one hand while holding the can 6 inches from the inside surface while spraying, to ensure an even coat.

Pour the grout from the bowl or bucket into the mold. Tap the sides and bottom of the mold gently, for approximately five minutes. This ensures that any air bubbles trapped in the mold are forced to the surface, so the grout can flow into all the nooks and irregular surfaces on the mold. Scrape off any excess grout from the surface of the mold with a knife, to smooth off the cast.

Stand the cast in a warm, dry location where it is less likely to be disturbed or subjected to cold temperatures that might affect the curing process. Wait 24 hours for the grout to set firmly. Turn the mold upside down. Tap the top and sides of the mold to force the grout cast out. Lightly sand the surface with low-grit sandpaper to remove any rough edges and imperfections.