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WHAT IS A REPRODUCTION MOULD?
The MASTER PATTERNS section of this site introduces the two types of master pattern used in the lost wax art foundry – the LOST PATTERN, and the PERMANENT PATTERN. When a permanent pattern is going to be used as a template for casting, the founder first has to create a REPRODUCTION MOULD from which a wax copy (the WAX PATTERN), can be made.
A reproduction mould is simply a negative impression of the sculptor’s artwork. Those parts of a design that are seen as high points on the master pattern’s surface (like a nose for example), are later seen as low points or 'impressions' in the reproduction mould; conversely, dips and depressions on the pattern’s surface are seen as raised high points when viewed in the reproduction mould. In some respects the reproduction mould is rather like a photographic negative, both the negative plate and rubber mould can be considered intermediate stages, used to transpose an ‘image’ from one medium to another.
In the art foundry, most reproduction moulds are used to create wax versions of sculpures for lost wax casting; though it is just as easy to produce copies in other materials, including plaster of Paris, resin, and even low melting point metals like lead. In most cases it is possible to use the same reproduction mould to produce casts using different filler materials.
TYPES OF REPRODUCTION MOULD
The simplest reproduction moulds are created by impressing a hard pattern image into a soft material such as clay. This leaves an imprint of the design in the clay, which can then be filled with wax or plaster; a crude, but occasionally effective moulding technique. The impression technique can be traced to the cuniform seal makers of Mesopotamia, who were casting in lost wax some 5500 years ago [ref]. Of course the limitations of this impression technique are such, that is of little use in today’s founding environment where mouldmakers are expected to accurately reproduce extremely complex and detailed forms.
FLEXIBLE REPRODUCTION MOULDS >
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