The Lost Wax Bronze Casting Process

Step 1) Making the Mold: Taking an original sculpture most often made in clay, a mold is made using rubber and plaster which is coated over the sculpture.
Step 2) Making the Wax Casting: Molten wax is poured into the mold to form layers of wax. This wax model is an exact duplicate of the original sculpted model.
Step 3) Casting the Wax: The wax is pulled from the mold and hand chased (re-detailed).
Step 4) Spruing: Wax rods (gates) and a pouring cup are attatched to the wax casting in just the right positions. This will assure a full metal pour.
Step 5) Casting the Ceramic Mold (ceramic shell): The wax casting is dipped into liquid ceramic shell material. On the first dip a fine powder is applied; on the next dip a coarse ceramic sand is applied. This is repeated several times, increasing the coarseness to create the ceramic mold. Between each dip the ceramic layer must cure (dry) before another layer can be applied.
Step 6) Burn-Out: The ceramic shell is placed in a kiln and fired. The shell bakes and the wax is melted (lost) from the shell. This creates a hollow ceramic shell mold. Thus the term “Lost Wax”.
Step 7) Casting: The ceramic shell mold is removed from the kiln and immediately the molten bronze is poured into the shell. At the time of pouring the bronze is 2100 F.
Step 8) Break-Out: After the casting has cooled, the shell is carefully broken away, leaving the unfinished bronze.
Step 9) Sandblasting: Any fragments of the ceramic shell are removed by sandblasting.
Step 10) Assembly: At this time all the pieces of the sculpture are welded together by the artist. Some large bronzes have over 20 pieces, each piece having gone through the above steps individually.
Step 11) Chasing: All the weld marks are chased (re-detailed).
Step 12) Sandblasting: After all the metal finishing has been performed the sculpture is sandblasted for a final time to ensure an even bronze finish for the patina.
Step 13) Patina and Waxing: The bronze is first heated with a torch, then the patina chemicals are hand applied. Several applications are applied in order to achieve the proper color qualities desired. The piece is then waxed with heat and polished to ensure a beautiful lustre.
Step 14) Mounting: The sculpture is then mounted on wood or marble depending on the artist’s preference.

Educational Pages
Art Mediums:

Anamorphic Art


White-Line Woodblock Prints...


Lost Wax Casting Process

Art History:

Dutch Old Master Treatise

Lineage and History of American Impressionism:
The Road to Annapolis

Art Preservation:

Custom Framing

Protecting your Art

How to Care for Bronze Sculpture

Care and Framing of Pastels


Frequently Asked Questions About Portrait Commissions

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