Sculpture Process

Fascinated by frogs and birds during his childhood adventures into the English woods, Tim Cotterill had no idea he would someday be known as the Frogman. The sculptor uses a process called the lost wax technique invented by the Egyptians thousands of years ago.

  • Drawing inspiration from his Venice Beach paradise, Tim works the lines until a clear vision of the frog forms in his mind
  • Once Tim finishes his sketch, he starts sculpting. First he welds a metal armature “skeleton” and then sculpts.
  • Once the shape unfolds, Tim refines the design.
  • Once finished, Tim Cotterill’s finished sculpture is brought to the Frogman Foundry to start the Lost Wax Casting Technique. A flexible silicon mold of the sculpture is made by skilled artisans.
  • A plaster backing is applied to the silicon rubber to provide strength and rigidity for the mold. After the plaster dries, the mold is pulled apart and the original is removed.
  • The mold is reassembled and hot wax is poured into the cavity to make a duplicate of the original sculpture.
  • After cooling and hardening, the wax is removed from the mold. It is an exact copy of Tim’s original sculpture.
  • Next. the wax sculpture is attached to wax runner bars to form a “tree”.
  • The tree is then dipped into a liquid mixture called a slurry. The wet tree is covered with a fine sand to start building a ceramic shell.
  • Over the next several days, successive coats of slurry and sand are applied to the sculpture to form a ceramic shell. It takes about a day for each coat to dry.
  • The hollow ceramic shell is fired in a kiln to bring the shell to its full strength. The shell is heated to a temperature of 1600 degrees for 3 hours.
  • After the final coat, the ceramic shell is put into a steam autoclave. the term “lost wax” comes from this step as the wax is melted away, leaving a hollow ceramic shell.
  • High quality Everdur bronze waiting for melting.
  • The heated shell is pulled from the oven.
  • The molten bronze is heated to over 1700 degrees and is poured into the heated shell.
  • After the bronze has had a chance to cool, the ceramic shell is chipped away to reveal the new bronze sculpture.
  • The bronze sculpture is cut from the runners, and then smoothed and polished by hand, When this process is complete, the sculpture is ready for patina.
  • The sculpture is treated with chemicals and fired with a blowtorch.
  • Different chemicals are used to create the different patinas that Frogman is famous for.
  • After the colorful patina has been completed, a clear coat is applied to seal the colors. the sculpture is inspected and necessary touch ups are completed.
  • The sculpture is buffed by hand, and then signed and numbered, completing the process.