Forming Methods

Part of Pottery and Ceramics

Forming is the stage where clay becomes a vessel, tile, brick, or any other useful shape. The method you choose — hand-building, coiling, slab construction, or wheel throwing — depends on your tools, the object’s purpose, and the clay’s properties.

Why Forming Methods Matter

Each forming technique produces different results in terms of wall thickness, strength, symmetry, and speed. Coil building requires no tools but is slow; a potter’s wheel produces symmetrical vessels quickly but requires significant skill and equipment. Understanding all methods lets you choose the right approach for every situation — and keeps production going when specialized equipment is unavailable.

Pinch Pots

The simplest forming method — no tools required. Pinch pots are the fastest way to produce small vessels and the best method for learning how clay behaves.

Technique

1. Start with a ball of well-kneaded clay, roughly fist-sized
2. Push your thumb into the center, stopping about 1 cm from the bottom
3. Pinch between thumb (inside) and fingers (outside), rotating the ball slowly
4. Work from the bottom upward, gradually thinning and expanding the walls
5. Keep the walls 6-10 mm thick — thinner risks cracking, thicker fires unevenly
6. Smooth the rim by pinching evenly all the way around
7. Set on a flat surface and adjust the base

Best For

• Small cups, bowls, and dishes
• Crucibles for metalworking
• Quick utility vessels
• Learning clay behavior before attempting advanced methods

The Two-Pinch-Pot Method

Make two pinch pots of equal size. Score the rims, apply slip (liquid clay), and press them together. You now have a hollow sphere — the starting point for round bottles, rattles, and enclosed forms that no single pinch pot can produce.

Coil Building

Coil building creates vessels of any size by stacking and joining clay ropes (coils). It was the primary pottery method for thousands of years before the wheel and remains practical for large containers that exceed a wheel’s capacity.

Making Coils

1. Take a lump of clay and roll it on a flat surface with your palms
2. Apply even pressure, working from the center outward
3. Target coil thickness of 1-2 cm diameter
4. Make coils uniform in diameter — variations cause uneven walls
5. Keep coils slightly damp; cover unused coils with a wet cloth

Building Process

1. Form the base — Roll a thick coil into a flat spiral, or press a slab of clay into a flat disk. The base should be 8-12 mm thick.

2. Score and slip — Scratch crosshatch marks on the top edge of the base. Apply slip (clay mixed with water to cream consistency). This is the glue between coils.

3. Place the first coil — Set a coil on the scored edge, pressing it firmly into the base. Overlap the coil ends by at least 3 cm and blend the joint.

4. Add successive coils — Score and slip the top of each coil before adding the next. Stagger the overlap joints so they do not stack vertically (which creates a weak line).

5. Blend the coils — On the inside, use your thumb or a smooth tool to smear each coil downward into the one below, creating a solid wall. Optionally do the same on the outside, or leave the coil texture for decorative effect.

6. Control the shape — Place coils on the inner edge to narrow the vessel, on the outer edge to widen it. Place centered to go straight up.

Coil Placement	Effect on Shape
Inner edge	Walls curve inward (closing)
Centered	Walls go straight up
Outer edge	Walls flare outward (opening)

7. Build in stages — For tall vessels, build 10-15 cm of wall height, then let it firm up for 30-60 minutes before continuing. Wet clay cannot support much weight above it.

Avoid Trapped Air

Press each coil firmly into the one below and blend thoroughly. Air pockets between coils cause separation during drying and explosive failure during firing. If you see a gap, open it and re-blend.

Finishing Coil-Built Vessels

1. Smooth the outside with a rib tool (a curved piece of wood, bone, or pottery shard)
2. Scrape the walls to even thickness using a trimming tool
3. Refine the rim — cut to a level line and smooth
4. Add handles, spouts, or decorative elements at the leather-hard stage (firm but not dry)

Slab Building

Slab building uses flat sheets of clay joined at edges and corners. It excels at making rectangular objects — boxes, tiles, stoves, and architectural elements — that are difficult to produce by other methods.

Making Slabs

1. Rolling method — Place a lump of clay between two guide sticks of equal thickness (set to your desired slab thickness). Roll with a smooth cylinder (a straight log or pipe), riding on the guide sticks to maintain even thickness.

2. Cutting method — Press a large lump of clay into a rough slab, then use a wire or string stretched between two sticks to slice even layers off the top.

3. Slapping method — Throw the clay down onto a flat surface from a height, rotate 90 degrees, and repeat until flat and even. Fast but less precise.

Joining Slabs

Step	Action	Why
1	Score both surfaces with crosshatch marks	Creates mechanical grip
2	Apply thick slip to both surfaces	Fills gaps and bonds clay
3	Press firmly together	Squeezes out air, ensures contact
4	Blend inside seam with a finger or tool	Creates continuous wall, hides joint
5	Add a small coil along inside corners	Reinforces the weakest point

Score and Slip — Every Time

Never join two pieces of clay without scoring and slipping both surfaces. Clay that is simply pressed together without this step will separate as it dries. This is the single most common cause of slab construction failure.

Best For

• Tiles and roofing tiles
• Rectangular containers and boxes
• Stove and oven linings
• Flat architectural elements
• Molds for other forming methods

The Potter’s Wheel

The wheel is the fastest and most elegant forming method. A skilled wheel-thrower produces a finished pot in 2-5 minutes — versus 30-60 minutes by coiling.

Building a Kick Wheel

A kick wheel uses the potter’s foot to spin a heavy flywheel, which maintains rotation momentum while the hands shape clay on the wheelhead above.

Components:

1. Flywheel — A heavy stone disk or thick wooden wheel, 50-80 cm diameter, 40-80 kg. Heavier is better — more momentum means smoother rotation.
2. Shaft — A straight, strong wooden post or iron rod connecting the flywheel to the wheelhead. Must rotate freely.
3. Bearing — The shaft pivots in a socket. A hardwood cup with tallow grease works; a metal bearing is better. The bearing must be low-friction.
4. Wheelhead — A flat wooden or stone disk on top of the shaft, 25-35 cm diameter. This is where the clay sits.
5. Frame — A structure to hold the bearing, support the potter’s seat, and keep everything aligned.

Centering (The Essential Skill)

Before you can throw anything, you must center the clay — make it spin without wobbling.

1. Wet the wheelhead and slap a ball of clay firmly onto the center
2. Wet your hands and the clay
3. Start the wheel spinning counterclockwise (for right-handed potters)
4. Press the clay inward with both hands, squeezing it into a tall cone
5. Push it back down into a thick disk
6. Repeat the cone-up, push-down cycle 3-4 times
7. The clay is centered when it spins without any visible wobble and your hands feel no bumps

Centering Takes Practice

Centering is the hardest skill in wheel throwing. Plan to spend hours practicing before you can reliably center clay. Use the same lump repeatedly — re-ball and re-center until it becomes automatic. Every other wheel technique depends on good centering.

Basic Throwing Sequence

1. Open — Press your thumb into the center of the spinning clay, creating a hole. Stop about 8 mm from the bottom.
2. Floor — Flatten and widen the bottom by pressing outward from the center hole.
3. Pull up — Squeeze the wall between your inside and outside fingers, moving upward. Each pull thins the wall and increases height.
4. Shape — Apply gentle pressure from inside to swell the form outward, or gentle pressure from outside to bring it inward.
5. Refine — Smooth the surface with a wet sponge or rib. Define the rim. Clean excess clay from the base.
6. Cut off — Slide a thin wire (twisted plant fiber or thread) under the base to separate the pot from the wheelhead.
7. Dry — Set aside to dry to leather-hard stage.

Trimming

Once the pot reaches leather-hard:

1. Invert it on the wheelhead and center it
2. Use a loop tool or sharp stick to trim excess clay from the base and foot
3. This defines the foot ring and removes the heavy base left from throwing

Molding

Using molds to shape clay is fast and produces consistent, repeatable results.

Press Molding

1. Carve or form a mold from plaster, stone, fired clay, or hardwood
2. Press a slab or lump of clay into the mold
3. Trim the edges level
4. Let the clay firm slightly, then remove from the mold
5. Repeat for identical pieces

Drape Molding

1. Drape a clay slab over a convex form (a rock, a bowl, a wooden shape)
2. Press into shape and trim edges
3. Once firm, lift off the form
4. This is how tiles and shallow dishes are mass-produced

Common Mistakes

1. Working too-wet clay — Overly wet clay slumps, collapses, and sticks to everything. Clay should be moist but firm enough to hold its shape. If it sticks to your hands, it is too wet.
2. Uneven wall thickness — Thick and thin areas dry at different rates, causing cracking. Check wall thickness regularly by pressing gently — the wall should feel uniform throughout.
3. Skipping score-and-slip — Joining clay without scoring and slipping guarantees failure. The joint separates as the clay dries and shrinks. Every join, every time.
4. Building too fast — Adding coils or height before lower sections have firmed causes collapse. Let the lower portion stiffen for 30-60 minutes before adding more height to tall forms.
5. Wobble on the wheel — If the clay is not perfectly centered, the pot develops uneven walls and eventually spirals off center. Re-center before continuing rather than trying to compensate.

Summary

Forming Methods — At a Glance

• Pinch pots: simplest method, no tools, best for small vessels and learning
• Coil building: versatile, any size, slow but reliable — always score and slip between coils
• Slab building: flat sheets joined at edges, ideal for rectangular objects and tiles
• Potter’s wheel: fastest method, produces symmetrical vessels, requires a kick wheel and significant practice
• Always score and slip when joining any two pieces of clay
• Build tall forms in stages — let lower sections firm before adding height
• Centering on the wheel is the critical skill — practice until it becomes automatic