Beginning Ceramics A

Slab Technique

Sheets or slabs used to form pottery objects offer large surfaces to decorate.  A rolling pin is used with wooden sticks (guide sticks) to ensure an even thickness.  The slab should be turned regularly, and rolling should take place from the center outward. This allows the clay sheet to spread more easily.  It is best to roll out a clay slab about 3/8 inch thick.

The clay slabs cannot support themselves when soft and pliable.  When all the flat clay pieces are cut, let them dry until the clay becomes slightly firm but not leather hard.  Score the edges and moisten them with slip, firmly press the edges together, and seal them carefully so they will not crack open later when they are dried or fired.  Tiny clay coils (for more strength) should be added along the inside of each joint and worked into the seams.  Smooth all joined edges with a sponge for a continuous surface.
 

You are to make two slab constructed forms.  You may select which of the three projects to complete.  You must make two different forms.

Box:  Cutting out cardboard or paper templates for each piece and using these as your pattern pieces for your form can form boxes.  This will ensure uniform shapes and sizes.  A lid for the box is formed by cutting out a slab and securing strips or coils to the inside of the lid to hold it in position when it is on top of the box.  Place the strips so there is a little play between the inside of the box and the strips.  If the box interior will be glazed, glaze will make the walls thicker.  When a lidded box or jar is dried or bisque fired, keep the lid in place on the bottom to deter uneven warpage that may prevent a good fit.  Minimum size:  5 inches.

Cylinder:  Wrapping a pliable clay slab around an empty plastic container covered with dry paper towel or plastic wrap can form cylinders simply.  The dry paper towel or plastic wrap allows for easy removal of the slab cylinder.  When you have the cylinder wrapped around the plastic container, you place it on top of another slab of clay and cut the base.  On the outside at the base, blend in the clay to attach the base to the cylinder.  Remove the plastic container by simply twisting the container.  Smooth out with a damp sponge.  Minimum size:  5 inches.

Luminaria:  Following either of the above directions for a box or cylinder can create a luminaria.  A luminaria must have cutout shapes in order to function as a luminaria.  The cutout shapes should be done when the slab is flat on the table surface.  A luminaria can be formed over a form but plastic wrap must be used because it allows for easy removal of the luminaria.  Minimum size:  5 inches.

Name or Address Plaque:  Cutting out a slab base can make a name or address plaque form.  Letters, numbers, and/or designs can be cut out separately and attached by scoring the surface on the base, applying slip, and blending the two surfaces together.  Be sure to include holes or another way for the plaque to hang.  Minimum size:  10 inches.