SCULPTURE AT THE GALLERY AT ICE
The Gallery at Ice represents renowned British sculptors as well as promoting contemporary sculptures by young emerging British and International artists. The Gallery Director has personally selected and sourced sculptures from the working studio of each sculptor.
The Gallery at Ice offers a diverse selection of bronze, bronze resin and mixed media sculptures for the home, garden and commercial interiors.
Bronze casting techniques
The technique of lost wax bronze casting is one of Man’s earliest technologies dating back at least 6000 years. During the third millennium B.C., ancient foundry workers recognised through trial and error that bronze had distinct advantages over pure copper for making statuary. Bronze is an alloy, typically composed of 90 % copper and 10 % tin and because it has a lower melting point than pure copper, it will remain as liquid for longer when filling a mould. It also produces a better casting than pure copper and has superior tensile strength.
The basic method of casting has changed very little over time; however modern craftsmen have some technical advantages over those of past times with welding equipment, power tools, efficient gas or oil burners and flexible rubbers for moulding. However, today’s process is still heavily dependent upon many hours of skilled labour and remains a ‘low tech, high skill’ craft.
Direct Lost Wax Method
The sculptor models his sculpture in clay, plaster or wax surrounding a metal armature and from this a Rubber Mould with a plaster jacket is made (usually 2 or 3 pieces).
Molten Wax is then painted on the inside of the mould to build a hollow wax model of the sculpture. The parts are then assembled and the joints hand – worked to blend in the surface. A mixture of fired clay and plaster are then put inside the wax to form a core. Pins are then pushed through the wax to hold the core in place.
A sprue system is made with hollow rods of wax; some will be ‘runners’, through which the bronze is poured into the mould and some ‘risers’ which allow the gases to escape. Around this usually complex wax sculpture system, a mixture of fired clay and plaster is placed to form the exterior mould.
The whole sprue system is then placed in a kiln and heated to harden the mould and to allow the wax to melt and pour out. Molten bronze (1,100 ͦc) is then poured into this mould and when the molten bronze appears at the top of the risers, the caster knows that the mould is filled.
Once cooled, the mould is chipped and broken away, which reveals an accurate replica of the wax model together with all the runners and risers also cast in bronze. The runners and risers are then sawn off and the core pin holes are welded, the bronze surface is worked and tooled to obtain the required finish. Suitable chemicals are then applied to attain the required colour patina.
The sculptor will finish the piece with a final waxing to seal in the patina.
Indirect Lost Wax Method
This process has the advantage that the original model can be preserved and further castings can be attempted in the event of failure, or if more copies are required.
- A model of the head is made in a suitable material, such as wood, clay or plaster.
- A plaster piece mould is taken from the model. The pieces must be able to be removed without damage to the model and therefore great care has to be taken with any under cuts.
- The piece mould is removed from the head and then reassembled. The inside is lined with wax sheets or painted with wax to an even thickness.
- The piece mould is removed and a diluted mixture of the mould material is poured into the head to act as a core. From then on the procedure is the same as for the direct lost-wax method.
Bronze Resin casting technique
The sculpture is modelled in clay, plaster or wax and from this a Rubber Mould with a plaster jacket is made (usually 2 or 3 pieces).
Particles of bronze filings are then mixed with a curing resin (about half and half) and then painted on the inside of the mould. The main objective here is to get the bronze filings onto the surface of the cast as dense as possible .
The cast is then strengthened with metal armature or fibreglass as necessary; the parts are then assembled and the joints hand worked to blend into the surface of the cast.
Suitable chemicals are then applied to attain the required colour patina and the sculptor will finish the piece with a final waxing to seal in the patina.