Hand building pottery: pinch, coil and slab

Start by wedging

Wedging is kneading for clay. It evens out soft and firm spots, lines up the particles and pushes out air pockets, which can show up later as bumps or weak spots. Two common methods are ram's head and spiral wedging. Both involve pushing the clay forward and down with the heels of your hands, then rocking it back, about 30 to 50 times. A teacher can show you either in a few minutes.

Work on canvas, unsealed wood or plaster so the clay doesn't stick. Avoid folding the clay over itself like bread dough, since folds can trap air.

Pinch pots

Roll a ball of clay about the size of an orange. Push your thumb into the center, stopping a finger's width from the bottom. Then turn the ball slowly while pinching the wall between thumb and fingers, working from the bottom up in small, even squeezes. Keep the rim a little thicker than you want at the end, because rims crack and thin out easily.

Pinch pots are a good first project because they teach you how clay responds to pressure and how fast it dries in your hands. Two pinch pots joined rim to rim make a hollow form for animals, rattles or ornaments. Poke a small hole in any closed shape so air and steam can get out in the kiln.

Coil building

Coils are ropes of clay stacked to build a wall. Roll them on the table with spread fingers, moving your hands outward so the coil stays even. Thick coils are easier to handle at first.

1. Cut a base from a flat piece of clay.
2. Score the edge of the base and the bottom of the first coil, add a little slip, and press the coil on.
3. Blend the coil into the base on the inside and outside with your thumb or a wooden tool.
4. Add the next coil on top, joining and blending each one as you go.
5. Let the lower part firm up a little if the wall starts to sag.

You can leave the coils showing on the outside as a pattern, but always blend them on the inside, where weak joins can open up.

Slab building

Slabs are flat sheets of clay rolled with a rolling pin between two wooden guide sticks, so the thickness stays even. Around a quarter to three eighths of an inch (6 to 10 mm) is a common thickness for beginners. Soft slabs can be draped over or into a form to make plates and bowls. Firmer slabs, left to stiffen to leather hard, stand up well for boxes, cups and planters.

Use paper templates for anything with straight sides. Cut edges at an angle where two slabs meet, so the join has more surface to grip.

Score and slip every join

Most hand building failures are joins that crack open during drying or firing. To make a join that holds:

• Join pieces that are at the same moisture level. Soft clay shrinks more than firm clay.
• Score both surfaces with a needle tool or serrated rib, making rough cross-hatching.
• Brush on slip, which is clay mixed with water to a thick cream.
• Press the pieces together firmly, then smooth a thin coil of clay into the inside corner.

Even walls, slow drying

Thick and thin areas dry and shrink at different speeds, which creates stress. Aim for walls of even thickness, avoid lumps thicker than about an inch (2.5 cm), and hollow out solid sculptures from underneath. Read the drying guide before you put your piece on the shelf.

A starter tool kit