An engobe is a material similar to a slip, with somewhat lower clay content, higher proportion of flux, and added filler, and in some cases a colorant.

As a material for sculptures he mostly used terra cotta, with engobe being his favourite pottery technique along with less frequently used faience and glazing techniques.

A coating of white or coloured slip, known as an engobe, can be applied to the article to improve its appearance, to give a smoother surface to a rough body, mask an inferior colour or for decorative effect.

With care it is possible to apply a second coat of engobe of a different colour to the first and to incise decoration through the second coat to expose the colour of the underlying coat.

Engobe has been used by potters from pre-historic times until the present day and is sometimes combined with sgraffito decoration, where a layer of engobe is scratched through to reveal the colour of the underlying clay.

Starting with red clay pottery they moved on to blue glaze and on red clay articles with engobe of white clay, painting floral designs with cupric oxide and applying a soft glaze containing glass and borax etc.