
The Wax Process
The Wax Casting Process
The silicone molds are used to create wax figures: molten wax is painted and poured into the negative rubber mold, producing a perfect positive copy of the original sculpture. The waxes are created hollow so that the finished bronze will be manageable in weight. The thickness is usually between 1/8 and 3/16 of an inch depending on the size and scope of the work.
The wax casting is removed from the mold. The positive copy will have seam lines where the parts of the mold meet together similar to those you might see on a plastic toy soldier or a chocolate Easter bunny. Our trained artisans hand finish the wax pattern to original perfection by dressing the wax seams down to the surface of the sculpture. Each wax casting is treated as though it were an original work of art. Often the artist will come and inspect the dressing before it is moved on to the next phase of casting to ensure that we have captured every detail to their exacting standards. We use two kinds of wax - a soft wax for the surface and a hard wax for support. We also recycle the wax from our burn-out and formulate our own unique blend of SHIDONI casting wax.
SpruingWax rods (gates and vents) are attached at strategic points to the wax pattern to allow the even flow of molten metal and to alleviate the trapping of air and gas. A sprue cup is placed onto the gates to receive the molten bronze. The same sprue system is used in reverse, or upside down, to melt the wax out of the ceramic shell mold. This is where the term Lost Wax Casting comes from. A second mold will be created around the wax pattern with its sprue system in which the bronze will be poured. We use a minimal sprue system that we developed at SHIDONI. This allows us to direct the bronze flow into the piece in as few places as possible minimizing the amount of turbulence and trapped air in the casting. This minimization also saves us time in the subsequent steps. Each sprue system is unique to the piece for which it is designed. The gates, vent and cup are all made with wax and are attached with heat.