Before you decide to begin tooling on sandstone, consider possible hazards and take safety precautions. Wear safety goggles to keep small pieces of stone from hitting you in the eyes while you sculpt or carve. A dust mask will keep particulates from infecting your lungs during the sanding process. Wear steel-toed boots to avoid broken toes resulting from falling pieces of stone. Before you begin working, check that all of your tools are in working order, especially electric or pneumatic tools.
Like all rocks, the hardness of sandstone varies depending on the ratio of its composite minerals---feldspar and quartz. If the sandstone has more quartz than feldspar, it will have a harder surface texture and require stronger tools. By contrast, sandstone heavy in feldspar has a softer composition. These minerals give sandstone its unique colors and patterns, making it a favorite for both construction purposes and art. The type of sandstone you intend to use will dictate the required tools.
Hammers allow you to break away chips of sandstone by striking the end of a chisel. Use a wooden mallet for softer sandstone; this will help you control your strikes so you don't take off too much material or miss your chisel altogether. Harder stones require the use of a soft-metal hammer. If you want to add a rough and natural look to the sandstone, use a bush hammer -- a tool with a head that mimics a meat tenderizer.
You will use three types of chisels when working with sandstone. Because of their increased resilience to dulling, carbide-tipped chisels work best for stone sculpting. Use a pointed chisel to sketch designs and add small details into the stone. Next, use a toothed-chisel to begin polishing the rough sketch you made with the pointed chisel. Finally, you will need a flat chisel to finish the sculpture. For softer sandstone, the pointed chisel may work for all purposes.
Once you finish sculpting, you will need sanding equipment to smooth edges and add texture. For hard sandstone, you need sanding equipment with diamond-tipped bits. Wet sanding -- soaking the stone with water before sanding -- will make the process easier. Use a small grinding disk to remove large sections of stone. For detail work you will need a rotary tool with a variety of diamond tipped bits. Sandpaper works well for polishing stone and adding a smooth texture; for softer types of sandstone it is the only sanding equipment you need.