The basics of throwing a large platter without warping

Throwing a large platter is less about speed than control. Uneven pressure, thin edges and a base that dries at a different rate from the rim can turn a promising disc into an oval once it leaves the wheel. Keeping the clay centred, maintaining consistent thickness and supporting the form through drying are the essential safeguards.

Clay may be the biggest variable. A body that is too soft struggles with the weight of a wide form, while a stiff or short-working clay can crack before the rim is opened. Learning to read the material and respond to each batch is what turns the basic throwing method into a repeatable studio practice.

Prepare the clay and wheel

Begin with a firm, plastic stoneware body that suits the scale of the platter. A little fine sand or grog can improve stability, although too much coarse grog makes the surface difficult to smooth. Clay suppliers around Melbourne and Sydney commonly sell dry stoneware by the bag, and studio scraps can be reclaimed, soaked and pugged before use. Never add water by guesswork; work it into the clay gradually.

Wedging removes air pockets and aligns the particles so the walls pull more evenly. Cut the block, drive it against the wedging table, then repeat until the clay feels consistent throughout. Fresh clay may need only a short preparation, while reclaimed clay can require more effort. It also helps to think of water and observation as connected studio concerns, a broader approach described in water and observation.

Clean the wheel thoroughly and attach a fresh bat before placing the clay. A damp, gritty wheel surface can drag the base sideways as the form widens. Make sure the wheel head and splash pan are balanced, and give the bat time to firm up. For a large platter, adequate wheel power matters; a slow, steady rotation is safer than a motor straining under the load.

Centre the mass before widening

Place the clay in a compact mound and press it firmly onto the bat. Begin centring with both hands around the clay, using firm downward pressure and keeping the mass centred between your palms. As the wheel turns, bring the hands higher and lower in small, controlled movements rather than trying to pull all the air out in one attempt.

The body should support the effort, with one elbow braced against the thigh or hip. This gives the hands a stable anchor while the clay spins. If the mass wanders, stop widening and use the rib to refine it. A centred lump may take longer to open, but it gives the platter a much more reliable foundation.

Centring is also a practical exercise in making fine adjustments. Watch the surface rather than relying on speed, and check the clay from several angles as it rises. Independent ceramic field notes can provide useful studio context, but the best measure remains your own observation of the clay’s movement under your hands.

Open an even floor

Once the clay is centred, press both thumbs into the centre and open the floor in stages. Move outwards from the middle while keeping the thumbs lower than the surrounding wall. Large forms are easily made lopsided at this point because a small opening pulls the whole mass off-centre.

Check the floor thickness with a needle tool before widening further. A useful starting point is roughly 8–12 millimetres for many stoneware bodies, although the clay and intended platter size determine the right depth. Too thin a floor can ripple under pressure, while an excessively thick floor adds weight and drying time.

If opening the floor by hand feels beyond your comfort level, a hand-building approach can offer another route into broad forms. This guide to a smooth coil-built pot shows how careful layering can produce controlled walls without relying on the wheel.

Build controlled wall thickness

Raise a short, even cylinder before shaping the platter. Keep the hands in contact with the clay between each pull, supporting the outside with the other hand so the wall does not thin in isolated patches. The fingers should lead the clay upwards slowly, with the rim compressed afterwards.

Move the clay upwards in several modest pulls rather than one long stretch. A tall cylinder gives you more control over the wall thickness than a compressed lump, and it creates a stable shape from which to develop the broad curve. If the upper section becomes thin, compress it gently and check the wall from inside and out.

Compression matters as much as stretching. Use the heel of the hand or a flexible rib to align the rim, firming any area that has begun to wander. Australian studio measurements are usually made in metric units, and a simple calliper can reveal variations that the eye misses. Even thickness reduces the chance that one section will shrink or distort more than the rest.

Shape the platter without stretching

Turn the low cylinder into a broad, shallow form by pressing down through the centre and guiding the clay outwards in controlled passes. Support the inside wall with your fingers while the other hand applies pressure to the outside. Never push only against the rim, as that creates a thin edge and an unstable curve.

Work in stages and rotate the platter as needed. A rib can smooth the surface and define the transition from the base to the wall, while a sponge can refine the centre. Measure the diameter at several points rather than assuming the form is symmetrical. If the wall flexes during shaping, move more slowly and reduce the pressure.

Allow the platter to stiffen before making final adjustments. Clay that is still soft will continue moving after you release it, so repeated corrections can introduce new distortions. Ease the rim into its final curve, compress the edge once more and leave the piece centred on the bat until it is firm enough to trim safely.

Trim, dry and fire evenly

Trim the foot ring while the platter is leather-hard, keeping the base flat and the walls slightly thicker than the rim. Cut the piece from the bat with a taut wire, supporting its full weight as you lift it. Place it on a level board or plaster bat sized for the platter rather than balancing it on a narrow surface.

Drying causes more warping than throwing in many cases. Cover the platter loosely so dust cannot settle on it, while allowing air to circulate around the base and rim. Melbourne’s changeable weather, Sydney’s humidity and the faster airflow in northern Queensland can all affect drying rates. Rotate the piece regularly and avoid artificial heat unless the entire form is warmed evenly.

Bisque firing requires another slow stage. Make sure the kiln shelf is level, leave enough space around the platter and avoid crowding its edge against another piece. A witness cone confirms the heatwork, but it cannot correct an uneven kiln. Follow the firing range recommended for the clay body, especially after adding substantial grog or a thick foot.

Glazing introduces fresh risks because some glazes shrink differently or cling heavily to vertical surfaces. Leave the foot clean for the kiln shelf and apply glaze evenly, including any areas that will handle food. Raku has its own thermal-shock concerns, particularly for wide forms; Amelia’s account of a first raku firing shows both the excitement and the unpredictability of that alternative process.

Make the next platter your project

Practice with smaller forms first, recording the clay body, wall thickness, drying method and firing result. This simple studio record helps you reproduce successful shapes and diagnose the exact stage where distortion begins. Once the process feels familiar, scale up gradually rather than adding several centimetres to every dimension at once.

Explore the available platters, decorative plates, sculptures and abstract pieces through Amelia Johannsen’s studio. The site also provides information about pottery workshops and hands-on clay experiences with wine and tapas. For an Australian audience, current availability, prices in Australian dollars and shipping arrangements can be checked directly, while Instagram and the mailing list offer updates on new work and upcoming events.