Miniature Bronze Figurines by Randall Zadar
Ancient Lost Wax Casting Process Used to Create Fine Art Bronze Miniatures
The process used to create Zadar Miniatures is the same process used to create bronze sculptures found in museums around the world. The process involves creating a master of wax, then encasing it in a plaster type material and burning (or melting) the wax out so that it becomes “lost.” The empty cavity is then filled with molten bronze creating the miniature figurine.
1.Starting with a special wax, the master design is sculpted. The sculpting time takes many hours to complete. Special tools are used to sculpt and hold the fragile wax. An amazing amount of detail can be achieved in the miniature wax sculpture, which is less than one inch in size.
2. A mold is made and additional was patterns are produced exactly like the master. The wax patterns are placed in a flask and then encased in a plaster type material called Investment. The flasks are slowly heated in an oven for 12 hours. The wax melts out and the flasks reach a maximum of 1350 degrees. This is called the ‘burn out’.
3. The wax formed a perfect negative impression of the sculpture in the Investment material and then melted out. The cavity is now filled by heating bronze until molten with a torch and forced into the cavity with a centrifugal casting machine. The casting is quenched in water to cool. The new bronze casting is thoroughly cleaned.
4. The bronze figurine is now inspected and mold lines removed. Each figurine is then sandblasted and prepared for paint. A white base coat is carefully sprayed. Custom colors are selected for each piece and the painting procedure begins. After the piece is completely painted and dry, it is varnished, numbered, signed and boxed. The miniature figurine is now ready for the collector.
A more detailed explanation of the process is below

Miniature sculptures start out with an idea, a picture, some tools and sculpting wax. It can take 50 to 200 hours to sculpt a master.

The wax master (on left) is destroyed in the molding process, but if the mold works properly, a perfect copy of the master is made (on right.)

One of the wax patterns from the RTV mold is cast into sterling silver. This now becomes the sterling master for the entire edition.

The production mold is now made from the sterling master. Pieces of mold rubber are placed around the master in the frame.

The flasks are placed inside the kiln and slowly heated to 1350 degrees. The wax slowly melts out and becomes “lost” this produces the negative cavity for the bronze to enter. The burnout process takes 12 to 14 hours.

The flasks are placed one at a time in a centrifugal casting machine and bronze is heated to 1850 degress.

When the bronze melts, the machine is released and it spins the molten bronze with centrifugal force into the cavity in the flasks.

The hot flasks are removed from the casting machine and quenched in cool water. This makes the bronze strong and helps break off the investment. This is a very violent reaction.

The Lost Wax Casting Process has many failures and rejects. The bronze can be reused but not the wax.
Thanks for looking.