White Portland cement, together with binding and stabilizing agents, creates a medium for fine art sculptures. The quantity of grinding and polishing of the last sculpture depends upon the artistic vision of the sculptor. Tools and materials used for this purpose range from homemade and found items to electricity grinding practices and tools.
Numerous tools are used to remove coarse roughness from concrete art sculpture. Working the concrete once it has hardened, but until it’s completely cured, the sculptor works with coarse to progressively finer tools for completing the surface of the sculpture. A rub brick includes a handle and can be used to knock larger coarse places. Rasps (special kinds of documents with regular rows of teeth cut to the surface) as well as rotary tools fitted with various carving bits, are employed in various grades of coarseness to further enhance the sculpture surface.
The sculpture could be garnished with wet/dry sandpaper or an oscillating grinder with a diamond grinder pad. You can even utilize a rotary tool with sanding accessories suited to concrete. During sanding, proceed the sandpaper, grinder or tool tip back and forth in a smooth movement. When using a power saw, do not push down hard onto the surface of the sculpture, but allow the tool to do the job. Use 110- to 120-grit sandpaper with this intermediate step in completing the surface of your concrete art sculpture.
If small holes or imperfections are found, use a slurry to smooth the surface. Mix cement and water to make a runny mix. Rub onto your sculpture. Allow to dry for about 20 minutes and then wash with a damp sponge. Smooth with a sanding tool. Repeat if air holes or other tiny imperfections stay.
Polish the finished cement sculpture with fine sandpaper. Begin with about 200-grit and finish with 400-grit. Following the sculpture is smooth, rub with dry talc, if desired, for extra polishing. Allow the cement sculpture to cure for about seven days. Apply a concrete sealer. Wax with carnauba or beeswax, if desired.