Project by Rusty Sieck from Pittsboro, N.C.
Rusty's large covered jar is inspired by an old Chinese jar, which was originally used for holding ginger. The jars Rusty makes are less formal, more whimsical; each one is decorated differently and no two are exactly the same.
Materials:
cone 10 stoneware clay body
porcelain decorating slip
cobalt carbonate
Spanish red iron oxide
broken pieces of glass
decorating stamps
scratch glazes made from slip clays
feldspars
kaolin
silica
wood ash
Steps:
1. Center an initial lump of clay (from 5 to 20 lbs. depending on the desired size of the finished pot) on the wheel and throw it into the form of the bottom half of the ginger jar. Use ribs to refine the shape of the pot and smooth the throwing lines from the outside.
2. Set this piece aside to dry until it is leather-hard (the rim may sometimes need to be covered in plastic to keep it from drying too fast). The drying time will vary from overnight to a couple of days, depending on the temperature and humidity.
3. When the base section has dried enough to support the weight of more clay (the clay should be leather hard from top to bottom, but not dry) the rim is measured with a pair of calipers or a ruler. Throw a ring of about the same amount of clay as the base (or a little less) to about the same diameter as the rim of the base. Form a gallery or groove in the rim of this ring, which should correspond exactly to the diameter of the rim of the base.
4. Remove the ring of clay from the wheel and place the base back on the wheel. After slightly wetting and scoring the rim of the base, invert the wet ring of clay directly onto the rim of the base section. Tap on the bottom of the bat to settle the wet ring of clay onto the rim of the base and then pass a cutoff wire between the bat and the base of the wet ring of clay and remove the bat.
5. With the wheel spinning slowly, seal the joint between the two sections of clay by working clay downward into the joint. Now, the ring of clay can be thrown into the form of the top of the pot. As before, use a flexible steel rib to smooth and refine the form. Using a wooden knife, trim the base of the pot to the desired shape, undercut the foot slightly, and pass a cutoff wire between the pot and the bat.
6. Measure the rim of the jar with calipers or a ruler and move the pot from the wheel to a moist place to dry slowly. On a new bat, center a pound or so of clay and throw a shallow bowl which will become the inverted form of the lid. The inside diameter should be just a touch larger than the outside diameter of the jar's rim. Pass a wire between the lid and the bat and set it aside to stiffen.
7. Once the lid is leather hard, invert it on the wheel and use a trimming tool or a piece of banding steel to trim it to the shape of a form you like. Score a ring in the center and attach a small piece of clay. Throw this clay into the form of a handle.
8. By this time, the jar should have dried somewhat and should be ready to be decorated. Start by coating the top half with a thick layer of porcelain slip. The top of the lid is usually coated with the same slip.
9. Take a look at the form and decide how it should be decorated. Pieces of glass can be stuck into the clay that will run down the sides of the pot as it is fired. Stamps, sea shells, dots of porcelain slip and rolled textures can be applied in patterns as desired. Roll a pattern onto the bottom half of the pot with a pastry wheel, toy truck tire, or notched piece of spring steel.
10. Remember that you will later be applying glaze to the pot, so leave room for it to interact with your other decorations. When you are satisfied with what you’ve done, set the pot aside to dry. It will take anywhere from 5 days to 2 weeks to dry completely, depending on the weather and humidity.
11. When the jar is completely dry (it will feel warm to the skin on the side of your face when it’s dry), sand off any rough edges and load it into a bisque kiln. Fire the jar to cone 04 with the lid in place.
12. After the pot is bisque fired, dip the base in wax to prevent glaze from sticking to the bottom of the jar. Then glaze the pot as you wish. Coat the inside of the jar with a celadon glaze, dip the bottom half in an ash base glaze, and then spray various glazes onto the top half of the jar with an air compressor and spray gun. Spray glazes especially thickly along the top so that the glaze will run down along the sides of the pot.
13. Once the pot is glazed, it is fired in a 50-cubic-foot propane-fired car kiln. The firing usually lasts about 12 hours from the time the kiln is lit until cone 10 is completely down. Once the kiln is shut down, it takes 2 days to cool; then it can be opened to see what emerges! Sometimes bits of kiln shelf or kiln wash will stick to the bottom of the pot; these can easily be rubbed off with a bit of silicon carbide from a kiln shelf or a piece of a grinding wheel.
Website: www.chickenbridgepottery.com
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