Sculpting a stone is a very old form of art, dating many years back. Actually, one of the world oldest stone sculptures made of marble, Michelangelo’s “David”, was completed in 1504. However this art is still relevant today and has been used to make amazing stone sculptures. Below are some basic techniques used in stone sculpturing. Read on.
Basic Techniques in Stone Sculpturing
Your first step in stone sculpturing is finding the perfect stone. There are so many stones that you can use such as limestone, granite, soapstone and alabaster. The choice of stone will depend on your experience in sculpting and your project size. It’s important that you have your specific subject in mind, and then need to find the stone that has a roughly similar shape to your intended sculpture. The closer the shape the better since less work and stone will be wasted.
When you have chosen the right stone for your sculpture, your next step is to have your tools get ready for the job. Some of the tools you will use include: masonry rod saw, rasps, files and chisels.
When sculpting a stone you use a method known as subtraction. Subtraction is a method whereby you remove all the materials that you don’t need.
Begin with roughing out your stone with masonry rod saw. This saw can cut in all directions and therefore allows you to cut the curves. It’s advisable that you trip with a saw since you will not only save time but can also save some of the small pieces of the usable stone. However a cut-off saw that has a diamond blade or an angle grinder can accelerate the roughing process.
Your next step is to refine your sculpture using a harmer, rasps and chisels. Make sure you firmly hold the harmer close to its head to allow better control; this will also make your work less strenuous. When you are striking the chisel keep in mind that you have to look at a point where you strike the stone, rather that the end you tap with your hammer. Remember some light tapping is all that is required. In order to avoid deep bruising and cracks that are difficult to get rid off, hold your hammer less than 45 degree to stone surface.
For the softest stones, rasps are the best; they get clogged very easily. Brass-Bristol brush is the best to clean them.
Start your filling when you are completely satisfied with your sculpture. Files add the fine details as they remove the all the deep gouges that were left by your rasps and chisels. Make sure your filling is thorough; this will much mean less time plus money that you will spend working with the sandpaper.
Your final step is sanding and polishing, however some artistes prefer to leave their sculpture with some rough texture. A soapstone sculpture can be dry-sanded using a steel wool or wet-sanding using silicone carbide sandpaper.
For a soft stone such as alabaster, soapstone and wonder-stone, begin with 180 or 220 grit, progress to 400 grit and finally to 800 grit. When sanding a tone sculpture, avoid rushing to your next grit level, always dry the sculpture for you to check for any deep stretches before you proceed to next grit (stretches are not easily seen in a stone).
For a harder stone, e.g. a marble, you have to progress to 1500 and then to 3000grit for the best polish. For that exceptionally lustrous grit 60,000 will do. For the very hard types, try using diamond sanding.
A soft stone can be polished using a linseed oil or a bee’s wax. Apply your oil to a piece of cloth, then rub the oil onto the sculpture.
After the last polish, your sculpture is now ready.