Slip casting is a ceramic forming technique in which liquid clay, known as slip, is poured into a plaster mould to create a hollow form. The porous plaster draws water from the slip, building up a layer of clay against the mould wall; the excess is poured away, and the resulting form is released once firm. It is the standard method for producing consistent multiples and complex shapes.
Although associated with industrial production, slip casting is also widely used by contemporary studio ceramicists who want to make editions or to achieve forms difficult to produce by hand.
How slip casting works
A plaster mould is made from an original model, in one or more parts. Liquid slip is poured into the mould, where the absorbent plaster begins to draw water out of the clay touching its surface, forming a skin of solid clay against the mould wall.
After a controlled time, the still-liquid slip in the centre is poured out, leaving a hollow form whose wall thickness depends on how long the slip was left. As the cast firms and shrinks slightly, it releases from the mould and can be removed, cleaned up and finished before firing.
What makes slip casting distinctive
Slip casting’s great strength is consistency and complexity. A single mould can produce many near-identical forms, making it ideal for editions and ranges. It can also reproduce intricate, undercut and highly detailed shapes that would be extremely difficult to throw or handbuild.
In contemporary practice, makers often use slip casting creatively – combining cast elements with handbuilt or thrown components, casting unconventional originals, or deliberately exploiting the qualities of the process. A slip-cast piece is no less a work of art than a thrown one; the technique is simply a different tool.
Collecting slip-cast ceramics
Slip-cast work is often crisp and refined, with even walls and precise detail. Where pieces are produced as editions, they may be numbered. The quality lies in the design of the original, the finishing of the cast and the glaze or surface treatment.
At Byard Art, where slip-cast work is available, each piece is presented as part of our contemporary ceramics collection.
