Lost wax bronze technique

CREATION OF THE ORIGINAL MODEL

Realization in clay,
plaster,
wax, …

MODEL MOULDING

  • Making a mould in elastomer.
  • Setting up = mould in 2 parts to bring out the original.
  • Elastomeric layer.
  • Plaster or resin shell with a casting cone.
  • Demoulding to reveal the original piece of art.

WAX CASTING (REPRODUCTION OF THE ORIGINAL ARTWORK IN WAX).

  • The mould is filled with liquid wax.
  • The thickness of the wax (=thickness of the bronze) depends on the time left before emptying the excess wax.
  • The wax is allowed to cool on the inside of the mould.

WAX REWORK

  • Recovery of the wax model (demoulding).
  • Touching up the wax.
  • Mounting of the future wax feeders and vents, thus allowing the future casting of the bronze.

COATING

  • The wax model is coated with refractory plaster.
  • If the wax is hollow, a core of refractory plaster is poured inside.
  • The core is held in place by nails and holes in the outer casing.

MELTING OF THE WAX

  • The entire model is heated in a furnace for 24 hours (depending on the size of the artwork).
  • The wax melts at 250°C.
  • Temperature is increased in phases to 700°C to ensure that all the wax is melted.
  • The void left by the wax will then be replaced by the bronze.

BRONZE CASTING – 1200°C

COOLING 

DEMOILING


Phase that lasts approximately 24 hours (depending on the size of the artwork).

Destruction of the plaster coating
to extract the bronze sculpture.

CISELURE

  • Cutting of the power supplies.
  • Trimming.
  • Sanding.
  • Welding.
  • Surfacing.

PATINA (COLOUR OBTAINED BY THE OXIDATION OF BRONZE).

  • Heating the piece and depositing copper nitrate (for green), iron nitrate (for brown), etc…
  • Blocking and protection of the patina with wax, cooling and polishing.

As a general rule in bronze art, the editions are 8 copies + 4 artists’ proofs. When the artist wishes to remake a sculpture, he starts again from the mould, makes another wax, …
This is why it is called a lost wax bronze technique!

© 2020 NYS Hervé. All Rights Reserved.