Most cement statues are cast in moulds. With this method, you can make multiple statues from the same mould. Making a mould for a statue is time consuming and complicated to do. Purchasing a ready made statue mould is costly. Yet you can make unique, freehand cement statues without a mould.
First, sketch out the statue on paper. Draw if from a number of different angles to get a feel for the size and volume of the statue.
Cut rebar to various lengths using a hacksaw to create an armature based on the drawing. Rebar is steel rod used to reinforce cement. Use wire and duct tape to put the pieces together. Assemble smaller sections first and then wire them as a whole to the main armature.
Put on thick work gloves and start cutting black, 14-gauge, steel-wire mesh. Lay it over the rebar and form and shape the general structure of the statue. Use wire where needed to pull the wire mesh in to hold a shape in place.
Mix up regular cement and water in a trough with a garden hoe. Add perlite or vermiculite to create a thick, stiff mixture. The addition of perlite or vermiculite will create volume without adding much additional weight. Hand pack or trowel this mixture through the 1/4-inch holes in the steel-wire mesh to build up the cement core of the statue. Allow the cement to set up.
Mix up sticky cement, which is a cement traditionally used in mixing stucco. Mix by volume, 1-part plastic cement, 1/2-part mortar clay to 3-parts mason's sand. Dry mix the ingredients first in a trough and then add enough water to make a stiff mixture. When trowelled onto the armature it should stay in place without slumping. Build up the general overall shape of the statue.
Take a course paint brush and stroke it across the surface of the sticky cement to create a criss-cross dry-brush pattern on the surface. This prepares the surface for the final coat of cement.
Trowel on a finish coat of sticky cement. This must be down while the previous layer is still damp. Finalise the shape of the statue. Use sculpture hand tools to shape and define any details. As the cement begins to set up, run the tip of the trowel over the surface to give it a smooth surface. Use small sculpture tools to carve into and refine details as the cement is setting up. During the hardening stage, think in terms of subtracting, rather than adding, cement to refine the statue.
Allow the cement sculpture to cure slowly over a week's time. Cover the cement sculpture with damp towels to slow down the drying process.
If you are creating a very large sculpture, take the cut rebar to be welded together. To tint the cement you can mix in lime-proof colourants during the dry-mixing stage.
When starting to create free-form cement statues, start small and practice working with the cement so you get a feel for what you can and cannot do with it. For very large statues have your rebar welded together and then hot dipped in molten zinc. This will keep the rebar from rusting. The rust can bleed through to the surface of the cement and cause rust stains. If you don't add your final finish coat when the dry brushed surface is still damp, and the cement dries out too much, you'll have to paint the form with concrete adhesive first before applying the final coat of sticky cement.