Pouring Directions and Finishes

Do not be intimidated by the idea of making your own stepping stones. The process is very simple and straightforward, especially if you use a CreteSheet to do the mixing and pouring.

Materials list

1. CreteSheet.
2. 80 lb bag of pre-mix cement, mortar or stucco mix.
3. Towels and plastic sheeting.
4. Mold release — silicone spray, vegetable, mineral or motor oil. Apply oil with an inexpensive paint brush or rag, removing excess oil with a paper towel or dry paintbrush.
5. Optional: cement pigments, available at home improvement centers, building materials suppliers and mason’s supply stores.

Directions for mixing and pouring into molds

1. Thoroughly coat the inner mold surface with mold release using a rag or inexpensive paintbrush.
2. Lay your CreteSheet on the ground and add your dry mix first, then add the appropriate amount of water. Hold the four handles and, with a partner or by yourself, alternately raise one corner at a time, tumbling the mixture over onto itself. Continue for approximately one minute until the desired consistency is achieved. You may need a little extra water; the goal is a mix resembling thick pancake batter.
3. The CreteSheet naturally forms a spout for pouring the mixture into the garden mold. Fill each mold approximately 1/3 full, then gently shake or tap on the ground to remove air bubbles; this also allows the mix to settle into the detailed surfaces of the mold. Once settled, fill the mold to the top, gently shaking to level the cement.
4. Cover with damp towels and plastic sheeting and allow to harden for 2 days. Unmold and allow to cure for another week before adding any surface finishes such as stains and paints. Then allow painted stones a couple more weeks of drying before sealing.

Decorative finishes

A wide variety of finishing materials are available from paint, hardware and craft stores. Take notes on procedures and quantities so that desired effects can be duplicated in future stones. Because there is an element of unpredictability in the finished appearance of concrete stones, mix up a small batch of test concrete and use that as your experimental canvas.

Sealants

Any surface coloring of stepping stones should be sealed to create a durable, lasting finish. Acrylic sealants are UV stable, inexpensive and easy to apply but have the softest, least durable finish. Solvent-based acrylic sealants generally perform better than water-based products for outdoor use, are UV-stable, and are recommended where a flat finish is desired. Water-based epoxy bonds well to concrete and is harder than acrylic sealants, but is not UV-stable — which is not an issue when applying iron oxide pigments, which are UV stable.

Powdered colorants

Iron oxide powders are the most common colorants used for dyeing concrete. Oxides come in a wide range of earth tones — brick reds, ochres, browns, greys, greens — and can be found in many home improvement stores as well as masonry supply houses.

The simplest use is to incorporate the powder into the still-wet concrete until you are satisfied with the strength of the color. Or sprinkle small quantities on the bottom of the mold before the cement is poured in; this yields a pretty mottling in the finished stone. Another technique is marbelizing: mix a batch using your CreteSheet, remove a portion, add dye, then loosely combine both batches, stirring just enough to create swirls of distinct colors before pouring into the mold.

Washes can be made from a slurry of Portland cement, powdered colorant and water. Unlike paints and sealants, washes can be applied immediately after removing the concrete from the mold. Dip an inexpensive brush in the slurry and paint over the surface, wiping the slurry off areas of high relief with a sponge or paper towel. Pools of slurry remain in the lower recesses, producing contrasts in color and texture. Allow 1–2 weeks of curing, then apply a sealant.

Paints, patinas and other finishes

Acrylic paint, even house paint, can be applied full-strength or mixed with water or a clear glaze medium and applied to the stone, then wiped off the elevated surfaces with a dry sponge or paper towel. Allow to dry before coating again. Paint may make the stone slippery for foot traffic; in that case add sand to the paint for traction, or use a traction additive. Antique metallic finishes, rusting kits and crackle glaze also work on concrete. Seal any surface finish with a concrete sealant.

Concrete stains and acid washes

Stains and acid washes are available in most home improvement and mason’s supply houses in a wide variety of colors and are painted directly onto concrete. Stains are typically acrylic resins containing silicone; acid washes are metallic salts suspended in an acidic solution. Remove any oil or release agent from the stepping stone with a soap and water solution before applying stains, and follow the manufacturer’s directions for use.