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|Medallic Art History||The Art Cast Medal||History of MASC|
THE ART CAST MEDAL
Paramount to the successful outcome of any medal is a starting point of a sound idea. Once in place, the idea can be tried in various ways through drawing and sketching until a finished and accurate one is achieved.
With this step completed, it is now time to translate the working drawings of the two sides of the medal (obverse and reverse) into slabs of oil based clay (plastilina) of the projected size. The tracings can be now resolved three-dimensionally by building up from the surface and carving into it. It is important, at this stage, not to include undercuts into the design.
The two sides are still separate at this point. With the resolution complete, plaster molds are poured and formed around the two sides. Once the plaster sets and cures, the clay can be removed and the plaster can be touched up where necessary.
Melted wax in now poured into the plaster molds which much be water saturated. The two halves will set quickly and can be easily popped out. Finally, it is time to assemble the front and back of the medal, achieving the desired thickness at the same time. Basically, the two wax sides are softened and stuck together.
Finishing and refinement of the completed wax is now to be undertaken. Each work in an edition will require all of these steps after the mold stage. With the wax complete, a system of wax pouring and venting rods and a pouring cup are attached to the model.
With the set-up complete, the first stages of the investment mold or shell are applied to the surface. It is critical that all details be accurately covered and that no pockets or air bubbles be allowed to form. The mold is reinforced and completed prior to placement in a burn-out oven where all traces of wax and carbon are removed. This requires heat at or near 1000 degrees E Once the mold is empty and still warm, molten bronze at over 2000 degrees F. is carefully poured into the cup hole.
Bronze sets remarkably fast and can soon be broken out of the mold. Now the metal work of the medal begins: the cups, rods and vents must be cut off and ground down, and the surface must be cleaned, chased, sanded, ground, polished or buffed by various means. Instant oxidization and colouration can be achieved through a variety of patinas. All of these steps can take a good deal of time.
With the bronze medal brought to a worked and satisfactory conclusion, the surface can be left to achieve an even richer patina or protected at this stage with waxes, oils or lacquers. There is no right or wrong way here. The piece is now ready for display in an exhibition or in a collection.
Richard McNeill, September, 2002 (edited by Saulius Jaskus)