The ceramic shell art casting process starts with creating a mold of the master model. The original sculpture is covered with a thixotropic rubber which hardens to create a reusable mold. This mold is reinforced so that it is stationary for the creation of a wax replica of the original model.
Wax is poured into the mold, taking care to fill all of the mold cavities in order to get complete reproduction of the original artwork. Once hardened, the wax pattern is altered to include wax runners or gates that will allow metal to eventually flow into the hollow pattern cavity. The arrangement of gates and sprues (which form the primary metal pathway) varies depending on the pattern.
The next step involves coating the wax tree in a slurry. Slurry is a mixture of liquid binder and flour refractory materials. Depending on the alloy being cast, drying time requirements, and number of coats desired, the binder and flour materials used may vary. If you are new to the process, we recommend reviewing the Introduction to Ceramic Shell Investment Casting for detailed recommendations.
Once the tree is dipped in the slurry material, and excess material is drained from the tree, it is then coated with sand - commonly referred to as “stucco”. This can be done in a variety of ways including: rainfall sanding, use of a fluidized bed, or by hand covering (the “cat box” method).
After each layer dries, the dipping and stuccoing steps take place again. This continues until the shell is completed. The number of coats will vary depending in part on the pattern configuration and the binder used in the slurry.
Once the dipping sequence is completed and each coat has air dried sufficiently, it is time to remove the wax from the mold. This is accomplished by use of an autoclave or a FlashFire dewax oven. The wax will melt out of the shell leaving a hollow cavity.
The shell is then placed into an oven where it is fired for a given period of time. This assists in strengthening the shell and removing any remaining wax residue from the shell.
Finally, the fired shell is placed in a bed of sand with the pour cup opening facing up. Molten metal is poured into the shell. The shell takes on the orange glow of the metal and eventually turns white as the metal cools. The shell is then removed, the parts are cut off of the tree and the finishing area takes care of grinding away any sign of metal from the gating.
Established to provide a one-stop, 24/7 information and shopping source for art casters, R&R's Art Casting Depot offers casters a complete line of well-established products in the art casting industry. These products have stood the test of time and have been staples in the art casting community for decades. Art casters taking advantage of R&R's Art Casting Depot product line have realized the following advantages in their facilities:
Visit www.artcastingdepot.com for a complete product listing.
SCULPTACAST waxes are formulated with the purest synthetic and natural raw materials available in the industry; producing extremely low ash content and enabling the cleanest burnout and most accurate reproductions allowable.
Characteristics such as flow, toughness, durability, replication of detail, ductility, memory and release have all been engineered into SCULPTACAST waxes for specific applications.
SCULPTACAST waxes are available in numerous formulas to meet virtually all requirements from hand forming to slush casting. Whether you are a sculpture artist or a foundry making sculpture castings, SCULPTACAST waxes have been designed to meet your specific needs.
R&R’s sales and technical teams work with you to identify your casting goals and customize a system that meets those needs. To schedule an appointment, contact your R&R Regional Manager or R&R’s technical team at 800.253.4502.