A sculpture can be additive, meaning you add material to a form until it reaches the shape you are making, as in putting clay on an armature, or working with direct plaster, or attaching things to a support. Metallic sculptures are made this way, creating a form in clay, then making a mold and casting it in bronze or some other metal. Assemblage sculptures are also additive, in that they take a number of objects and arrange or attach them to form a larger piece.
Rodin worked this way, creating clay forms on an armature (support structure) then having the final pieces cast in bronze. Additive sculpture allows for a certain fluidity of form that is difficult to achieve in carving, simply because clay is so malleable it shows tool marks, directionality and the hand of the artist in a very direct way.
Subtractive sculpture involve removing material from a large piece to achieve a sculptural form. Woodcarving and stone carving are both examples of subtractive sculpture. The process of working in wood or stone isn’t the same, since the materials behave quite differently, but in both cases the artist needs to visualize the form inside the stone or the wood and remove only the material that does not belong in the final piece. This is true of both three dimensional forms and surface carving, like woodwork for cabinets.
Tools for wood sculpting
Although sculpting wood does not necessarily require much carving, having a carving knife nearby is useful. You can use a carving knife to smooth out and cut in the precise details of a wood sculpture. The size of the carving knife depends on what kinds of projects you create, but serious sculptors often keep a variety of knives on hand. You can also use a handheld rotary tool, equipped with a carving or engraving accessory, to cut intricate details.
Chisels and Gouges
Woodworking chisels and gouges are essential for removing sections of wood as you sculpt. Smaller chisels and gouges can be used to cut in fine details, while larger ones remove big chunks. Unlike working with stone, you don't need a vast range of chisels for wood sculpting. Flat-edge chisels will suffice, although they produce a rough-hewn surface that may or may not be desirable. Straight and skewed chisels are helpful for sophisticated sculpting. Buying a chisel set will offer you a choice of chisels with which to work. U-gouges are common woodworking tools that you may find indispensable. These tools come in various cutting widths, called sweeps, with straight or curved shafts. V-gouges are designated by sweep width and the angle of the V-shaped bottom edge.
Mallets come in a range of sizes and are used in conjunction with chisels to sculpt wood. Rubber mallets work exceptionally well because you are not as likely to inflict damage on the wood. Steel hammers may be used, as well, but they are heavy and not as easily managed as rubber mallets. Having a small, medium and large mallet available prepares you for wood sculpting jobs of any size.
Wood sculpting power tools are similar to those that woodworkers use to craft furniture and cabinetry. A handheld rotary tool is particularly useful because of the many accessories available for shaping and carving wood. If you are experienced with a chainsaw, you can use it to carve large wood sculptures. Many woodworkers use a handheld cutting tool or circular saw instead of a chainsaw. In addition to these tools, other power tools may prove handy for carving, cutting and sanding tasks. An oscillating tool equipped with a sanding accessory, for example, is ideal for sanding in tight spots and corners.