Ceramic Arts & Perception — Ceramics Technical
Ceramics Art & Perception

Throwing Classical Porcelain in Jingdezhen, China

Steve Brousseau takes us through the steps

Throwing Classical Porcelain in JingdezhenJingdezhen classical porcelain is unlike any other clay. Westerners have described its properties as like throwing cottage cheese. The first porcelain of late 10th century Song Dynasty consisted of one ingredient, chinastone felspar, petunze in the local dialect. The rock was ground into a paste by water-powered hammer mills, a practice still in use today. The restrictions of throwing wet powdered stone resulted in the intimate wares of Song and Yuan dynasties. Kaolin clay, gaolin, was discovered around 500 years ago during the Ming Dynasty in the mountain village of Gaolin. This addition of white gaolin clay to the petunze gave a structure to the porcelain and made possible the throwing of large forms, both as complete pieces and in the sectional cylinders of the body-height vases.

Throwing Classical Porcelain in JingdezhenSince the Ming period, the composition of the porcelain body has remained 60 per cent chinastone and 40 per cent kaolin. Both materials were traditionally made into brick shapes and mixed together. Before the invention of the pugmill, craftsmen would wedge a large mass of clay with their feet into a circular mound. Now it is pugged and then lightly rolled towards the body. Containing no ball clays and thus having little plasticity, classical Jingdezhen porcelain is an adventure to throw. The general rule is to throw thick walled pieces and, when thoroughly dry, trim both the inside and outside to desired thickness. As much as half the body will be trimmed away. The wheel is run on a large and powerful electric motor with pulleys. An old-fashioned lever that clicks into notches regulates the speed, much like the old farm tractors. Thick bats, more than one metre in diameter, are centred on the wheel head and stay in place by the sheer weight of the clay.

Throwing Classical Porcelain in Jingdezhen

The next step is to get a dozen or more of the 10 kilo porcelain balls on to the wheel. The growing mound is centred one ball at a time until a sufficient mass is attained. Initial centring requires the help of an assistant grasping the hands of the master thrower and forcing his energies through the master’s hands to centre the clay. At some studios two assistants steady the master’s hands for centring and opening. The centred clay is then opened and the bottom is quickly widened to its desired measure. The walls are raised progressively and then shaped. An assistant’s hands are used in the throwing until the final shape is near. The last shaping is completed by the master alone until the form reaches 1.5 m in diameter. The apparent simplicity and ease belie a master’s touch with a difficult material. The rim is carefully measured with a stick. Many shapes are parts of a two or three piece finished form.

Sections are assembled after the pieces have become bone dry in the sun and each section has been rough trimmed. A slurry of pancake batter consistency is made with the trimmings from the specific pieces to be joined. This is poured on to the rim of the bottom piece and the top section is lowered and centred. Within 10 seconds the trimmer begins to shave the assembled form to a final shape. The tools are kept razor sharp. It takes four men to haul away the porcelain form on a wooden platform with handles and take it out into the sun to dry. If it does not crack here it will make it through the firing. Attempting to trim Jingdezhen porcelain before it is dry is folly because the tools gouge out chunks of clay. The tools and the process must follow the nature of the material. A final soaking of the surface with a thick round brush dipped in water reveals any imperfections such air bubbles which must be removed.

Classical Porcelain in Jingdezhen

Cobalt blue qinghua decorationCobalt blue qinghua decoration is frequently brushed on to to the greenware by skilled painters. A clear glaze is applied with spray gun – formerly by spray can and strong lungs. All Jingdezhen wares are once-fired at 1300–1330°C in propane gas kilns – the old coal-fired kilns are being phased out. Enamels or gold lustres can be added with an additional firing at 800°C.
Jingdezhen is the home of nine of the 26 Masters of Art and Craft of China, the highest national accolade. This title is generally reserved for the decorators. The unsung craftsmen throwers are hidden away in factories and one stumbles upon them to watch in awe at their tremendous skill and humbleness. During the events of the Jingdezhen 1000 Years Celebration of Porcelain taking place in 2004 and 2005, visitors will be rewarded by a guided tour to the factory studios to learn the secrets of classical porcelain techniques, including the virtuosity of the master throwers.

 

 

Ceramics Art & Perception — Cermaics Technical
Ceramic Arts & Perception — Ceramics Technical
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