The Use of Armatures : An armature in a sculpture is a material used for supporting the weight of the clay. An armature is usually necessary when portraying a figure in motion or in a standing posture. The armature serves as the underlying support to the sculpture. In some cases, a skeletal formation can be made out of wire, or another materials such as pipe or aluminum, that will help hold the clay in place, so that the clay can be worked and detailed. When working with large sculptures, weight is an important issue. After the initial armature is constructed, sculptors often use fillers such as styrofoam or aluminum foil to fill out the form and reduce the amount of clay being used. If most of the mass of the armature can be made with filler, then the clay on top will be just a thin skin instead of a huge mass that risks falling off. Once the armature is built, the clay sculpture can then be formed around and on the armature. The armature holds the parts of the sculpture in place, allowing the sculptor the freedom to move the clay along the armature to get the form that he or she wants. For bas reliefs, an armature can be constructed which consists of a grid of screws connected with wires to prevent the clay from sliding. Finishing the Clay in Preparation for Moulding : Once the final touches have been made to the original clay sculpture, the final procedure before molding is touching up delicate details and smoothing the surface of the clay to perfection. This is quit important because any error or imperfection in the clay would be copied in the molding process and would appear in every subsequent stage. Thus, the smoother the clay, the less work will needed on the wax replica and the finished bronze casting itself. Hook tools, or rake tools, are often used to cut the clay down to a new contour and to leave small raised ridges on the surface. for smoother surfaces, rubber or metal kidney tools can be used. For really fine surfaces, a brush and a solvent are used to whisk away all tool marks. Once the desired smoothness has been achieved, the piece should be allowed to dry throughly before continuing to the molding process.