Coil building is one of the oldest methods of forming pottery, predating the potter’s wheel by thousands of years. It requires nothing more than clay, water, and your own two hands. For anyone who wants to make a simple bowl but does not have access to a wheel, this technique offers a direct and satisfying way to shape a vessel from the ground up.
The process is straightforward: you roll long ropes of clay, called coils, and stack them in a spiral or circle to build the walls layer by layer. With careful attention to joining and smoothing, you can create a bowl that is both sturdy and pleasing to the eye. This guide takes you through every stage, from preparing the clay to the final finishing steps, and includes common pitfalls to avoid.
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Materials and Tools
Before you begin, gather the following:
- Pottery clay – A medium-grained stoneware or earthenware clay suitable for hand-building. Avoid very soft or sticky clays; a plastic but firm body is best.
- A rib tool – A wooden or metal rib helps shape and smooth the walls. A simple kidney-shaped rib works well.
- A sponge – A damp natural sponge for smoothing and controlling moisture.
- A scoring tool – A fork, a serrated rib, or even an old toothbrush can be used to scratch the clay surface before joining.
- Slip – A thick, creamy mixture of the same clay and water. You can make it by soaking a small piece of clay in water and stirring until smooth.
- A knife or needle tool – For trimming excess clay and cutting coils.
- A banding wheel (optional) – A rotating turntable makes it easier to work around the bowl evenly.
- A kiln – Your piece will need a kiln firing to become permanent ceramic. The tutorial assumes you have access to a kiln or community studio.
Preparing the Clay
Start with a lump of clay that fits comfortably in both hands (about 500–800 grams for a small bowl). Knead it thoroughly – this is called wedging – to remove air bubbles and make the clay uniform. A simple spiral wedge on a clean plaster or canvas surface works well. Fold the clay onto itself, press down, and rotate. Do this for about two minutes until the clay feels smooth and pliable.
Once wedged, form the clay into a ball and pat it into a thick disc about 1 cm thick. This will become the base of your bowl. Set it aside, covered with a damp cloth to keep it from drying out.
Rolling the Coils
Now take a fist-sized portion of clay and roll it into a sausage shape on your work surface. Use your palms, starting from the centre and moving outward with even pressure. Aim for a coil about the thickness of your thumb – roughly 1.5 cm in diameter. Keep the coil consistent; if it thins in places, it will create weak points in the wall.
Roll several coils at once and store them under a damp cloth. For a small bowl, about five or six coils of 30–40 cm length should be enough. As you become more skilled, you can roll longer coils to reduce the number of joins.
Building the Base
The base of your bowl is the thick disc you prepared earlier. Place it on your work surface (or on a bat on the banding wheel). Use your thumb and fingers to pinch the edge upward slightly, forming a shallow rim about 5 mm high. This rim gives the first coil something to grip onto.
Attaching the First Coil
Take one coil and lay it gently along the outer edge of the base, following the curve. The ends should overlap slightly; trim the excess with a knife so that the coil forms a continuous ring. Now comes the most important part: scoring and slipping. Using your scoring tool, scratch the clay on the rim of the base and on the underside of the coil. Apply a thin layer of slip to both scratched surfaces, then press the coil down onto the rim. Use your index finger to make a bonding pinch – press down and slightly inward along the coil, spacing the pinches about 1 cm apart. This locks the coil into place.
Once the coil is attached, blend it into the base wall with your fingers or a rib. The seam should disappear entirely. A well-joined coil will not crack later.
Photo by Earl Wilcox on Unsplash.
Adding Subsequent Coils
Repeat the process for the next coil. Lay it on top of the previous one, stagger the join so the ends of coils do not sit directly above one another – this strengthens the wall. Score, slip, and pinch as before. After each coil is attached, smooth the join on the inside and outside. Use your rib tool to scrape down any bumps and your sponge to water-smooth the surface if needed. The bowl will begin to grow in height.
As the walls rise, you can start shaping the bowl. For a simple rounded bowl, press the coils outward slightly as you add them. If you want a straighter side, stack the coils directly above each other. You can also gently coax the clay from the inside with one hand while supporting the outside with the other.
Controlling Wall Thickness
Even walls are crucial for a bowl that survives drying and firing. Check the thickness regularly by pressing your thumb lightly against the wall – it should feel about the same all around. If a spot feels thicker, shave it down with a rib; if too thin, add a small coil or patch of clay and blend it in. A common beginner mistake is making the base too thick while the walls are too thin. Aim for a uniform thickness of about 6–8 mm.
Work at a steady pace. If the clay begins to dry out and crack at the seams, lightly mist it with water and cover the bowl with a plastic bag between sessions. On the other hand, if the clay becomes too soft and slumps, let it stiffen for a few minutes before continuing.
Finishing the Rim
When the bowl has reached the desired height (typically 8–12 cm for a small bowl), finish the top rim. Roll a final coil slightly thicker than the others. Attach it as before, but this time blend it gently so that the rim remains defined but not sharp. You can round the lip with a damp sponge. A smooth, even rim finishes the bowl nicely.
Trimming and Refining
Once the bowl is complete, let it sit uncovered for 15–20 minutes until it becomes leather-hard – firm enough to hold its shape but still damp enough to carve. At this stage, you can trim the foot (the bottom edge) with a needle tool or knife. Place the bowl upside down on a padded surface and carve a shallow recess to create a stable base. Also smooth any remaining fingerprints or tool marks with a damp sponge.
Photo by SwapnIl Dwivedi on Unsplash.
Drying and Firing
Drying must be slow and even to prevent cracking. Cover the bowl loosely with plastic for the first few days, then gradually open the plastic over another week until the bowl is bone-dry. If you rush drying, the rim will dry faster than the base and cracks will appear.
Once fully dry, the bowl is ready for its bisque firing – typically around 950–1000°C, depending on your clay. After bisque firing, you can glaze the bowl (optional) and fire it again to the clay’s maturation temperature. Follow your clay supplier’s recommendations.
Common Mistakes to Avoid
- Not scoring and slipping thoroughly – This is the most frequent cause of cracks. Always scratch both surfaces and apply slip before joining.
- Letting coils dry out – Keep unfinished work covered. If coils become stiff, they will not bond properly.
- Uneven wall thickness – Check regularly. Thick bases and thin walls lead to warping and breakage.
- Joining coils too quickly – Work deliberately, ensuring each seam is blended before moving to the next coil.
- Using too much water – Overly wet clay becomes weak. Use slip sparingly and a damp sponge, not a wet one.
With patience and practice, coil building becomes a rhythmic and reliable method. The bowl you make will be your own – every fingerprint and curve tells the story of your hands at work.