After the pattern has been removed from a steel mould, the face of the mould and particularly any sand projections subject to the wash of the metal, are stuck with wire nails more or less close together. The heads of these nails are often visible in the face of the mould, and their imprints may be seen on the surfaces of many steel castings.

The surface of the mould is sprinkled with molasses water or similar sticky preparation to make the sand hold together better, and a powder or wash of ground quartz or other pure silica is dusted or brushed over the entire mould surface and over the parting adjacent to the mould cavity, to make these surfaces highly refractory. The molasses water also aids to hold this silica facing, as the facing is not adhesive itself.