Make sure that your clothes, skin and work surface are protected. Wear protective gloves and a protective respiratory mask when working with concrete.
Cut off the back of a cardboard letter.
Brush the inside of the cardboard letter, including the cut-off piece, with two layers of liquid latex. Let dry and then brush the inside with cooking oil.
Mix the concrete according to the instructions on the package.
Pour the concrete into the mould. Carefully shake the letter and knock on the outside to bring any air bubbles up to the surface.
Place the cut-off part of the letter back on the concrete and tape in place with masking tape. This will allow the letter to retain its shape and stability.
Let the concrete harden for 1 to 2 days before opening the mould and removing the concrete letter.
Sand any edges and unevenness with sandpaper. Then let the concrete dry completely.
Cast silly, encouraging and beautiful messages in concrete! Use cardboard letters as a mould for the concrete. If you want to be able to stick your concrete letters into a flower bed, insert a metal rod into the mould before you add the concrete. You can also make a complete word by cutting up the letters and taping them together before casting. It requires a bit of work, but looks fantastic. Concrete letters are also perfect book ends for your bookshelf, or for decorating your home with words that make you feel good.
NOTE: It is best to mix concrete outdoors because of the dust it gives off. Find a shady spot out of direct sunlight so the concrete does not dry too fast and crack.