US Patent 7370688 Lost wax moulding method with contact layer

A method of manufacture of a multilayer ceramic shell mould whereof at least one contact layer out of a wax master pattern or a part to be manufactured, or other similar material, includes a step of preparing a first slip containing ceramic particles and a binder; a step of dipping the master pattern in a first slip; a step of forming the contact layer, and a step of depositing sand particles particles onto the layer and drying the contact layer. The ceramic particles of the slip are mullite particles and the slip includes a texturing agent.