Coil Building

Part of Pottery and Ceramics

Building pottery by stacking and joining coiled ropes of clay — the most versatile hand-building method for vessels of any size.

Why This Matters

Coil building is the oldest and most widely practiced method of making pottery without a wheel. It requires no equipment beyond your hands and a flat surface, yet it can produce vessels of any size — from small cups to massive storage jars that would be impossible to throw on a wheel. Nearly every pre-industrial pottery tradition worldwide developed coil-building independently, because it works with minimal technology and maximum flexibility.

For a rebuilding community, coil building is the method you’ll use before you can construct a potter’s wheel, and you’ll continue using it alongside wheel throwing for large or asymmetrical forms. Water storage jars, fermentation crocks, grain storage vessels, and large cooking pots are all easier to coil-build than to throw, even when a wheel is available.

The technique is also forgiving to learn. Unlike wheel throwing, which requires significant practice before producing usable vessels, a beginner can make a functional coil-built pot on the first attempt. Speed comes with practice, but basic competence comes quickly — an important advantage when your community needs pottery now, not after months of training.

Preparing Coils

Rolling Technique

1. Start with a well-wedged piece of clay about the size of your fist
2. Place it on a smooth surface (wood, stone, or canvas)
3. Using both palms, roll it back and forth while moving your hands outward from center
4. Apply even pressure — the coil should maintain consistent thickness along its entire length
5. Target diameter depends on the vessel:

Vessel Type	Coil Diameter	Wall Thickness After Smoothing
Small cups, bowls	1-1.5 cm	4-6 mm
Medium pots, jars	1.5-2.5 cm	6-8 mm
Large storage vessels	2.5-4 cm	8-12 mm

Consistent Thickness

If your coils keep getting thin in the middle and thick at the ends, you’re applying too much pressure at center and not enough at the edges. Spread your fingers wide and roll with your entire palm, not just the heel of your hand.

Coil Length

Roll coils about arm’s length (60-90 cm) for manageable handling. For small vessels, shorter coils are easier. Never try to wrap an entire large vessel with one continuous coil — the clay dries unevenly and joints weaken.

Keeping Coils Moist

Prepared coils dry quickly, especially in warm or windy conditions. Cover unused coils with a damp cloth or hide while working. If a coil develops surface cracks, it’s too dry — re-wedge it with a small amount of water.

Building the Base

Every coiled vessel starts with a solid base:

Flat Slab Base

1. Take a ball of clay and flatten it with your palm on a smooth surface
2. Use a stick or flat tool to roll it to an even thickness (8-10 mm for most vessels)
3. Cut to your desired shape using a knife or sharp stick — round for most pots, but rectangular or oval bases work too
4. Place the base on a portable surface (a flat piece of wood, a fired clay disc, or a large leaf) so you can rotate the vessel as you build without lifting it

Coil-Spiral Base

For very large vessels where a slab base might crack:

1. Start a coil in a tight spiral on your work surface
2. Continue spiraling outward until the base reaches the desired diameter
3. Smooth the coils together on both top and bottom by pressing and smearing with your thumb
4. This creates a base with no weak joints, since the clay grain follows the spiral

Stacking and Joining Coils

The Stacking Process

1. Score the attachment surface — use a sharp stick, fork, comb, or your fingernail to roughen the top edge of the base (or previous coil) where the new coil will attach
2. Apply slip — brush or dab a thin layer of liquid clay (slip) onto the scored surface. Slip acts as glue.
3. Place the coil — lay it along the scored, slipped edge, pressing gently to make contact
4. Join the coil ends — where the coil meets itself (completing a circuit), cut both ends at a 45-degree angle so they overlap and join seamlessly rather than butting bluntly
5. Weld the interior — using your thumb or a smooth stick, smear the clay from the new coil downward onto the previous coil at a 45-degree angle, blending them together
6. Weld the exterior — repeat on the outside, smearing upward or downward
7. Repeat — add the next coil on top of the one you just attached

Score and Slip Every Joint

Skipping the scoring and slip steps is the most common cause of coil-built pots cracking along the joints. Clay does not bond well to smooth clay. The scoring creates mechanical interlocking, and the slip fills gaps and provides a wet surface for fusion.

Interior vs. Exterior Smoothing

You don’t have to smooth both surfaces. Strategic choices about which side to smooth affect the vessel:

• Smooth both sides: Strongest joint, cleanest appearance. Standard for most functional ware.
• Smooth inside only, leave coils visible outside: Decorative effect; the exposed coils create a textured surface. Still structurally sound if interior welding is thorough.
• Smooth outside only, leave coils visible inside: Not recommended — the interior joints are harder to inspect and more likely to harbor leaks.

Shaping Techniques

Controlling the Profile

The shape of a coiled vessel is controlled by where you place each successive coil relative to the one below it:

Coil Placement	Effect on Shape
Directly on top	Walls go straight up — cylinder shape
Slightly outside the previous coil	Walls flare outward — bowl or open jar
Slightly inside the previous coil	Walls curve inward — closed form, narrow neck
Alternating inside and outside	S-curve or complex profiles

Building Outward (Bellying Out)

For wide-bodied vessels like storage jars:

1. Place each coil progressively further outward
2. Support the exterior with your hand or a curved paddle as you weld the interior
3. Don’t go too fast — if the wall leans out too far before the clay stiffens, it will slump under its own weight
4. Build 3-4 coils, then let the clay firm up for 15-30 minutes before continuing

Building Inward (Closing a Form)

For necks and shoulders:

1. Place each coil progressively inward
2. The interior becomes harder to reach as the opening narrows — use a stick or spoon-shaped tool
3. Support the interior wall with one hand while welding with the other
4. For vessels with very narrow necks, build the neck as a separate cylinder and join it to the body

Letting Clay Set Up

Large vessels cannot be built in one session. The lower coils must stiffen enough to support the weight of the coils above. A practical rhythm:

1. Build 8-12 cm of height
2. Cover the top edge with damp cloth to keep it workable
3. Let the lower portion firm up for 1-4 hours (depending on humidity and temperature)
4. Resume building

Overnight Joins

If you stop building overnight, the rim will be much drier than the interior. Score deeply, apply generous slip, and add a thin initial coil to re-establish a wet-on-wet bond before continuing with full-sized coils.

Finishing the Surface

Smoothing Tools

• Fingers: The most versatile tool. Wet fingers for smoothing, dry for texturing.
• Smooth stones (river pebbles): For compacting and polishing the surface
• Ribs: Curved pieces of gourd shell, wood, or fired pottery used to smooth and shape the exterior
• Scrapers: Flat tools for removing excess clay and evening walls
• Paddles: Flat wooden tools used to compact walls from outside while supporting from inside with a stone (called paddle-and-anvil technique)

Paddle and Anvil

This technique transforms coil-built vessels from thick-walled and rough to thin-walled and strong:

1. Hold a smooth stone (the anvil) against the inside wall
2. Strike the outside with a flat wooden paddle
3. The clay compresses between paddle and anvil, thinning the wall, smoothing the surface, and welding coil joints more thoroughly
4. Work systematically from bottom to top, rotating the vessel
5. This can reduce wall thickness by 30-50%, dramatically improving both strength and appearance

Burnishing

For a glossy, semi-waterproof surface without glaze:

1. Wait until the vessel is leather-hard (firm but not dry)
2. Rub the surface with a smooth stone, bone, or the back of a spoon
3. Use firm, overlapping strokes — the surface compresses and develops a sheen
4. A well-burnished surface repels water better than an unburnished one, though it’s not fully waterproof

Common Problems and Solutions

Problem	Cause	Solution
Cracks along coil joints	Insufficient scoring/slip; coils too dry	Score deeper, use more slip, keep coils moist
Walls slump or collapse	Building too fast; walls too thin	Let lower sections firm up between building sessions
Uneven wall thickness	Inconsistent coil diameter or uneven welding	Roll coils more carefully; measure with calipers or a stick gauge
Vessel leans to one side	Unequal pressure during welding	Rotate the vessel frequently; apply equal force on all sides
Rim cracks during drying	Rim dried faster than body	Cover rim with damp cloth between sessions; dry entire vessel slowly
Base cracks	Base too thin; dried too fast on bottom	Make base 10mm+; dry on a porous surface; lift and rotate daily

Scaling for Community Production

A single potter using coil building can produce 3-5 medium vessels per day. For a community needing hundreds of pots for water storage, cooking, and food preservation, organize production as follows:

1. One person rolls coils while 2-3 others build — division of labor dramatically increases throughput
2. Standardize sizes using simple measuring sticks for diameter and height at each stage
3. Use molds — build the first 3-4 coils inside a fired clay mold (a bowl shape) for consistent bases, then continue free-form above the mold
4. Batch process — build 10-20 vessels to the same stage, let them set up together, then advance all to the next stage

Coil building will likely remain your primary vessel-making method even after wheel throwing is established. Large storage vessels, wide-mouth crocks, and irregular shapes are all more practical to coil-build. Master both techniques and use each where it excels.