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How to Make a Bronze Mold

Making bronze reproductions allows the original sculpture or form to be transformed into a durable, permanent object. The "Lost Wax Method" is one of the oldest and most commonly used techniques for transferring an original form to a mold ready for the bronze pouring process. Many artists have the craftsman ability to make their own bronze molds, but lack the ability to pour bronze. Local foundries often offer the service of bronze pouring if you give them the bronze mold.

Things You'll Need

  • Modeling clay
  • Silicone rubber
  • Brushes
  • Plaster
  • Wax
  • Ceramic medium
  • Ceramic kiln
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Instructions

    • 1

      Prepare the original object with supportive clay. Lay the object on a flat worktable. Fill in the under section of the object with clay. Stop filling in halfway up the object and create a flat plane perpendicular to the side of your object. This creates the platform that the rubber will rest on.

    • 2

      Layer successive coats of silicone rubber over half of the surface of the object with a brush. Allow the rubber to dry in between coats according to the manufacturer and stop when the entire surface is covered. Leave space at the bottom of the object for later pouring. This space should be the surface of the object that rests on the floor when stood up or laid down.

    • 3

      Make the second half of the rubber mold. Release the rubber, remove the clay, and flip the original object over. Repeat Steps 1 and 2 for the other half.

    • 4

      Create the mother mold because the rubber mold needs a casing to ensure its form after the original object is removed. Paint layers of plaster over the surface of the rubber. Start with one half and when completely covered and dry, flip and coat the other half. Allow time according to the manufacturer in between coats for the plaster to dry.

    • 5

      Create the wax positive. Separate the two halves of the mother mold and removing the original form. Melt the wax according to the manufacturer. Rejoin the mother mold and flip the mold on its head so the pouring channel is facing up. Pour enough wax into the mold so that the entire internal surface gets a coat. Allow the wax to dry before adding a second coat. You want the wax to have at least a 1/4-inch width.

    • 6

      Make the ceramic mold. Remove the mother mold from the wax positive and dip the wax positive into the ceramic medium. When dipping, don't dip the bottom of the wax positive into the ceramic medium. This will leave an area for pouring. Dip several times until a thick casing forms around the wax. Allow time for drying depending on the manufacturers instructions in between each coat.

    • 7

      Drill several small holes into the backside of the ceramic mold. These holes allow the wax and air to escape from the mold during firing. Fire the mold in a kiln set at 1,500 to 1,600 degrees Fahrenheit.

    • 8

      Allow the ceramic to cool and plug up the escape holes with clay. Re-fire the mold in a kiln set at 1,500 to 1,600 degrees Fahrenheit.

    • 9

      Remove the mold from the kiln when cool. The bronze mold is now ready for bronze pouring.

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