The manufacture of chinese bronzes

Methods:

Before the years 30th, it was admitted that the first chinese bronzes were made following the lost wax technics. This method consisted in the use of a wax model, realised around a refractory clay matrix, having the same size than the desired vessel. The decoration was hand carved or printed on the wax. This model was then coated with a liquid clay containing a refractory matter and then with several clay coatings to form a mould all around the vessel. During the firing, the wax melts and escapes by special holes, letting a empty space between the core and the mold. It is in this space that the melting bronze was casted. Once the bronze was cold, the mold was broken and the vessel cleaned. During the excavations, the archeologists discovered grey terra-cotta molds prooving that the Shang also used the direct casting. These molds were single or in two pieces for the casting of weapons and farm tools but were in 4 pieces or more for the rituals vessels. So, for the Jue, the core of the vessel was melted in a 4 pieces mold assembled with tenon and other molds were used for the legs and the "buttons". In some cases, the legs and the bails were casted separately.

The principal steps are:

1) The first step, may be the most important for the beauty of the object consisted in the making of a matrix in terra-cotta.
2) On this matrix, they then proceeded in negatif by the application of several clay coating of about15 mm. After firing, this negatif was then shared in the different parts of the mould.
3) In a sand box, these pieces were assembled to form the external part of the molds.
4) An internal core was then placed inside, letting a 5 to 15 mm space between this core and the moulds.
5) The liquid bronze was then casted in this space.

Some exemples of grey terra-cotta.