< DIE CASTING
CONTINUOUS CASTING
Continuous casting is a process that allows regular cross sectional material such as hollow tube etc, to be produced in extended lengths. A reservoir or TUNDISH is supplied with molten metal which is then fed into a gravity tool. Molten metal passes from the tundish down through a former or DIE whilst being refined and cooled with directed water jets. Reminiscent of EXTRUSION and similar hot forming processes, continuous casting is a specialist manufacturing technique of limited use to individual artists and designers, though it may be a suitable means of producing regular architectural features such as long straight columns and similar cross sectional designs.
CENTRIFUGAL CASTING
This sand casting technique broadly follows the same principal as jewellery centrifugal casting by spinning a sand mould at speed – though in this case at lower revolutions than usual for investment work. The centrifugal force of the spinning mould throws the charge into the furthest recesses of the mould cavity, concentrating any foreign material that might cause inclusions into pre-set drains, outside the body of the cast. These drains can later be cut off and removed without damage to the design’s fabric. In theory, lighter and more detailed casts can be obtained with this process than possible with gravity sand casting. However, various difficulties such as balancing and setting the mould to spin correctly, means that centrifugal casting in sand is not especially helpful for producing irregular shaped artworks.
CUTTLEFISH CASTING
Casting metal into a cuttlefish mould is a simple, direct and time honoured jewellers technique used to create inexpensive, small scale cast reproductions. The ‘back bone’ of the fish, which is principally composed of CALCIUM CARBONATE, is divided into two (or sometimes more), pieces. The face of each piece is abrasively worked to a flat surface, thus creating a simple BI-VALVE MOULD when the two sections are reunited. The ‘negative image’ design can then be cut into the relatively soft surfaces of each face using a knife or other tool. Alternatively, a hard pattern can be impressed into the bone to leave a negative mould impression. Channels and incisions are added to create a cup, running system and vents. The sections of the cuttlefish mould are registered and reunited, then bound tightly together with a restraining wire. For further security, the mould can be buried in sand before filling with metal.
ELECTROFORMING, RESIN CASTING & ETCHING >
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