Wet sand casting is the oldest technique. Foundry sand is a mixture of refractory sand (silica) and a binder (bentonite) which is moistened and mixed in a grinder. This mixture is used to design single-use moulds. The part to be reproduced is called the master model. It can be made of wood, resin or metal. The model will be slightly larger than the part to be obtained, in order to take into account the shrinkage of the cast metal during cooling.
The model will be placed halfway in a metal frame filled with sand packed with a bat. A second frame prepared in the same way will cover the first one in order to follow the shape of the piece. The model is then removed and grooves are made in the sand to feed the model's impression during casting.
Once the mould is made, the casting process can begin. The molten bronze (1050°) is ladled from the crucible and poured into the mould. The casting must be carried out at a regular speed and adapted to the desired piece.
The unstamping consists in removing the molten piece from the mould by breaking the sand mould. This mould will be made repeatedly for each new production.
