< PERMANANT PATTERNS
CLAY & FIRED CERAMICS
Clay plays a central role in sculpting both as a creative and technical medium. Many clay varieties have excellent tactile characteristics which makes them an ideal choice for artists who want to work with a modelling technique. As well as being excellent for modelling, clays are also economic (recyclable), and relatively safe and simple to store/handle in the studio environment.
Most artists use grades specifically prepared for modelling, such as ‘buff’ modelling clay, though other natural and processed clays (including proprietory trademarked non-drying and oven fired materials), are no less useable if preferred.
Fired clay objects, for example earthenware (terracotta and other porous materials), raku (clay with added fireclay grog), bone china (calcinated bone, stone and clays) and porcelain (plasticised china clay with feldspar and silica), can also be used as foundry patterns.
The main difficulty in using un-fired clay as a pattern material, is the ever present problem of keeping the original design safe and intact during transportation and processing in the foundry. Designs formed in any soft material will always be vulnerable in a foundry environment, even if carefully handled. As a rule, the use of untreated clay for lost wax foundry patterns cannot be recommended, though many artists do supply their founder with patterns of this kind. Firing a clay design may prevent the work from drying out and remove the risk of accidentally smoothing off features; but fired ceramics are still relatively fragile, can crack during firing and it can be impossible to sucessfully fire large scale models..
Some sculptors arrange for their founder to mould clay models in the studio, it may even be possible to hire a temporary studio at the foundry when constructing larger works. Neither solution is entirely satisfactory as 'in studio' moulding by foundry technicians can be expensive, and it may not be practical for an artist to work in a foundry workshop..
Although clay makes for an excellent modelling medium, it is also very poor master pattern material. By far the best solution here involves a translation technique that enables the artist to utilise the best working qualities of clay, and then fix the finished artwork as a permanent hard copy, suitable for transportation and foundry processing. This sculpting technique is known as ‘waste moulding’.
WASTE MOULDING >
|
