3D Printing of Self-glazing Ceramics: An Investigation into Egyptian Faience

Stephen Hoskins and David Huson at the Centre for Fine Print Research at the University of the West of England are continuing their research into the 3D printing of ceramic bodies by investigating the possibilities of using techniques developed by the ancient Egyptians to produce a 3D printed ceramic body that will glaze itself during the firing process. Egyptian faience was the first glazed ceramic material invented by man. Originating in the fifth millennium BC, Egyptian faience is not a clay-based ceramic but is composed of quartz mixed with alkali fluxes. In contemporary terms Egyptian faience is popularly viewed as a low plasticity turquoise coloured self-glazing low-fired body, used primarily to create ornamental objects such as beads and jewellery. In its original Egyptian context faience was a versatile material, used in a variety of ways and in a number of different forms, to create objects such as sculpture, cups, vessels, funerary figurines, tiles, boxes and body ornamentation all with a highly coloured lustrous glaze. The two methods used in ancient Egypt to enable self-glazing in one firing are efflorescence glazing and cementation glazing: In efflorescence glazing soluble salts are introduced in to the body mix, after forming and during the drying stage these salts migrate to the surface of the formed article and during firing fuse and react with the body materials to form a glaze on the surface, by introducing colouring oxides such as cobalt, iron, manganese or copper into the mix a range of coloured glazes can be produced. In cementation glazing the article that has been formed is surrounded in a saggar (a refractory box used to support and protect a ceramic object during firing) by a powder consisting of a glaze precursor, during the firing process a eutectic reaction takes place between the ceramic article and the glaze precursor powder and a glaze is formed on to the surface of the ceramic article, the firing temperature is below the melting temperature of the glazing powder so that the glazed ceramic article can be removed from the powder bed in which it was fired. There is an interesting and coincidental synergy between the material properties of ancient Egyptian faience and the material requirement for the successful 3D printing of ceramic powders, this paper will describe the technical aspects of the ancient process and indicate how by using modern materials and methods the process can be replicated by 3D printing. There are additional potential benefits for the arts and crafts sector as the process will enable the production of glazed ceramic articles with only one firing and at a much-reduced temperature than conventional ceramic bodies allow.