THE CASTING PROCESS

Mould

STEP 1

The sculpture is laid on a bed of clay and a mould of silicon rubber is created. With larger sculptures the rubber is applied directly in sections before a rigid fibre glass jacket is applied on top creating multiple pieces for casting.

Mould Making Casting Process Lockbund
Mould Making Casting Process Lockbund
Wax

STEP 2

Wax is meticulously painted into the details of the mould in many layers of hot wax.  The mould is then assembled and slushed with wax to create an exact hollow replica of the sculpture. The wax is then fitted with sprues that allow the bronze to flow in during casting and the air to flow out. 

Wax Paint-Up Mould Making Casting Process Lockbund
Wax Paint-Up Mould Making Casting Process Lockbund
Ceramic

STEP 3

Over the next five days, the wax is covered with multiple layers of ceramic shell to make a strong white investment. Pins and wires are also added for extra support to the shell.

Coating Process Lockbund
Ceramic shell process Lockbund
Casting

STEP 4

The ceramic shell is then fired. The wax melts away from the inside of the shell leaving a negative space, for the bronze to be poured in to. In the foundry, the bronze is heated to 1200ºC and then carefully poured into the investments.

De-Wax Process Lockbund
Casting Process Lockbund
Chasing

STEP 5

The ceramic shell is broken away from the casting to reveal the bronze. This is then ‘finished’ by craftmen using metal-working tools. Sculptures that are cast in pieces are welded together and fine detail is added where the sprues once were to create a finished raw bronze that shows no sign of the casting process it has been through.

Knock-out Casting Process Lockbund
Chasing Casting Process Lockbund
Finishing

STEP 6

The final colouration is then applied to the bronze, using heat and chemicals for different patina effects.

Patination Chasing Casting Process Lockbund
Finishing