Three workshops shape plaster models used to create the moulds that are in turn used to produce porcelain objects, while in the turning workshop the paste is shaped directly on the wheel.
The shaping of Sèvres porcelain involves a number of specialized crafts, notably turning, calibrating (plates), moulding and repairing (sculptures), large-scale casting and small-scale casting. Certain workshops (turning, calibrating and moulding/repairing) require a consistent, so-called “plastic” paste, similar to modelling clay in texture. Other workshops (small- and large-scale casting and cutting/trimming) require a liquid paste called barbotine.
The drafter draws up the revolution-piece designs necessary for turning, calibrating, large-scale casting and plaster moulding, thus ensuring the pieces’ proper dimensioning. The shaped objects (excepting bisques) are pre-fired at 980° C. This temperature (relatively moderate for porcelain) allows the pieces to retain the necessary porosity for the subsequent clear-enamel application.
In the workshop dedicated to dip-enamelling, each object is rapidly immersed in the enamel bath; after drying and verification by brush, the objects are fired at a high temperature (up to 1,380° C at Sèvres) within the so-called “white kiln”. At this stage, the porcelain pieces are solid, thoroughly vitrified and translucent.
Porcelain service pieces and vases are never sold “white” to avoid sur décors (designs applied by the purchaser), except for certain artistic creations. Bisque works, for the most part sculptures, are fired at high temperature directly after shaping in a so-called bisque kiln, then sent to the polishing workshop.
Today, three types of kiln are used: Gas kilns for high temperatures and electric kilns (called muffles) for low temperatures. Two of Sèvres’ six remaining wood-burning kilns dating from the 19th century are still used for exceptional decorative pieces fired at high temperature; these round, brick kilns rising nearly 10 metres require specialized ancestral skills passed down from generation to generation.