Using Hump Molds in Slab Construction
With just a slab roller or a rolling pin and your imagination you can create great projects from tiles to fountains to furniture, not to mention pots and boxes.
By using slump or hump molds you can make complete sets of identical bowls and dishes Slabs of clay take textures well, so by pressing or rolling objects into the surface of the clay slab or by pressing the slab into a texture mold, you open the door to all kinds of possibilities for decorative surface effects.
Rolling slabs out with a slab roller is much quicker and easier than using a rolling pin and allows you to maintain identical thickness for plates, dinnerware, and other projects which require exact measurements.
First the clay is placed between two strips of canvas, then it is fed into the roller by cranking the two rolls.
The thickness of the slab is easily adjusted with no boards or shims; the roll opening and the handle are locked into place, and the knurled rolls grip the canvas and pull the slab through quite easily.
Slabs which are wet can be moved on the lower canvas.
Once the slab is removed from the roller it can be textured with a texture mold or by placing lace, leaves, seashells, or other found objects on the top surface and gently pressing the texture into the slab by hand or with a rolling pin.
Shapes can be cut out with a fetting knife and then allowed to dry until leather hard or when a light touch on the surface of the clay no longer leaves an imprint.
Flat objects, such as tiles, can now be bisque fired and then painted with glaze or with glaze pencils or chalks and then overglazes.
Three-dimensional projects such as jewelry boxes, square or rectangular vases, and model buildings or furniture are built up by joining slabs together.
First score the edges to be joined and then glue them together with slip before bisque firing.
The basic clay slab can also be shaped by hand while still pliable to create masks, pinching up the nose and chin and pushing in eye sockets, then defining cheek bones, brow, and mouth until the form takes the desired expression.
Details such as lips and eyebrows can be shaped from coils of clay and glued in place with slip.
To make dishes, bowls, and other dinnerware it is easiest to use slump or hump molds.
Hump molds can be obtained in a wide variety of shapes and depths.
The slab is placed over the hump mold and pressed gently into it until it acquires the shape of the mold.
After it has dried to leather-hard, it is trimmed to its final shape with a fetting knife and pried from the mold.
Remember that all ceramics which will come in contact with food must be glazed with non-toxic lead-free glazes.
These are just a few suggestions for the infinite variety of ceramics projects which start by rolling out a simple slab of clay.