Sculpture From Clay To Bronze : Part 6

Metal chasing is the process of finishing the metal back to the appearance of the original. This process usually involves a fair amount of welding with a high frequency welder. Grinders are often used to remove spures. Angle grinders with a variety of different grades of Roloc pads are used to finish the surface of the bronze. Always start out with a courser pad and then work your way down to a very fine pad when chasing the metal. It may also be necessary to retexture some areas of the bronze. This can be done with a tool known as a pencil grinder. This tool uses a variety of high speed burrs, some of which are quite similar to those used by a dentist, to perfect the final bronze. If the sculpture being created was rather large or complicated, it might have been cut into pieces during the mold stage. This is necessary in order to be able to make molds that would be small enough to pour bronze into evenly. That is, instead of one big mold for a large piece, the piece may have been broken up into five or ten different smaller pieces, each piece with its own mold. Each smaller mold would thus be a different part of the whole sculpture, so that when all of the pieces have been poured and chased, they can then be fit back together to create the whole piece. If this is the case, all of the separate bronze pieces must be welded together to create the whole sculpture again. A metal welder will use a high frequency welding torch to carefully weld the sculpture together. After the sculpture is welded back to one piece, all of the weld lines must also be chased away so that they disappear and it looks as though the sculpture was all one piece to begin with. When the final piece is all welded together and chased to perfection, the bronze is next sand-blasted or bead blasted to make it very smooth and shiny. Using a sand-blast cabinet is the most convenient way to sand-blast a sculpture. The sculpture is placed inside of the cabinet and the lid is closed securely. A worker can insert their arms into the cabinet through holes on the side of the cabinet which have gloves attached to protect the worker’s arms. Wearing these protective gloves, the worker can then operate the sand-blasting compressor while monitoring the progress through a window in the cabinet. After the sculpture is sand-blasted, the sculptor once again inspects the piece for accuracy. Now that the bronze has been sand-blasted, its true gold-like color, almost like glowing platinum, is visible. The sand-blasting also makes the surface of the bronze more porous, allowing the top surface to be more open to penetration of the patina in the next stage. – To be continued.