// SLI P C AST ING STE P B Y S TEP
Slip casting step by step
The 4| height on top of a container. The
Place two wooden sticks of uneven
uneven height is important because this allows the slip to run down the sides and prevents stalactite droplets from forming in the base. Turn your mold upside down and place on the sticks. Leave to drain; do not reverse the mold too soon s this can cause wet areas to run back; the cast should have a matt, waxy sheen.
A slip-cast object is a satisfying thing. It is the reward of all the investment of time making the model and molds.
1| blunger or with a handheld blender. Prepare the slip by mixing in a
Ensure the mold is completely dry and place a tight rubber band or cord around the outside. This will prevent the mold from opening once it is full of slip. If your mold does not have a spare (see p. 93), place a coil of clay around the top of the mold to create a slip reservoir.
2| molds, have a couple of jugs of slip
Fill a plastic jug with slip. For large
on standby so a continuous pour can be maintained. Pour the slip carefully into the mold. Aim for the center and not the sides. Pouring too fast can cause casting spots or swirl marks. Pouring too slowly risks filling lines or causing variations in thickness. Fill the mold and keep topping up the slip reservoir.
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3| slip, size of mold, and consistency of Casting times vary on the type of
slip. Allow approximately 20 minutes for an earthenware and semi-porcelain body. Bone china and porcelain take much less time, approximately three minutes. After this time, the slip can be tipped out. This should be done steadily—not too slowly, as this can cause draining marks, and not too fast because this can create a suction that can pull the cast away from the mold. If you hear a glugging sound, tip back the mold slightly and ease the flow.
Once the cast is touch-dry and has a matt sheen, trim away the spare with a sharp scalpel. A blunt knife will ause the cast to crack. Be careful not to ut or scratch the mold. Tidy and sponge he rim.
Techniques to try Casting slip can be colored with the addition of 10% stain to 2 pints (1 liter) of slip. Try experimenting with painting or slip trailing colored slip inside the mold before filling the mold with white slip.
6| to 1 hour. Discard your first cast as Empty the mold after 30 minutes
this may be contaminated with plaster.
7| hard or green state, remove seam
When the cast has dried to leather-
The finished cast will appear to have a flush decoration in the surface. To emboss the cast, lightly scratch into the plaster mold and brush away any loose bits of plaster. Secure the mold and fill with slip.
lines with a sharp knife or scalpel (this is known as fettling) and sponge the area. andle the piece as little as possible.
// GAL LER Y: S LIP CAS TI NG A ND MOL DS
Gallery: slip casting and molds Christie Brown (UK) Entre Chien et Loup, 2003/4 Each figure H: 51in (129cm), W: 10in (25cm), D: 10in (25cm) Ceramics and mixed media Brown’s work encapsulates an ongoing interest in multiples, repetition, and the metaphors associated with molds.
James Rigler (UK) Valley, 2007 Approx. 9ft 10in (3m) by 6ft 6in (2m) Glazed earthenware; press-molded ceramic; plaster molds taken from sledged/lathed/ assembled plaster models, then press-molded, bisqued, and glazed The layout of the elements means the piece can vary in size and shape to interact with its site.
Ruth Borgenicht (USA) Gray Moon, 2008 H: 15in (38cm), W: 13in (33cm), D: 5in (12.5cm) Stoneware; slip-cast, unglazed, colored casting slip; fired to 2372°F (1300°C/cone 10) This artist uses the chain-mail pattern and other woven patterns to create ceramic works that conjure up a sense of permanence and defensive concealment.
Sasha Wardell (UK) Large Shoal Vase, 2008/10 H: 15in (38cm) Slip-cast bone china, layered and incisedwith colored/stained casting slips
Maria Lintott (UK) Bloom Jugs, 2009 H: 3in (8cm), Dia: approx. 3½in (8.5cm) Slip-cast fine bone china with hand-applied floral sprigs
