Pmag
Pottery Technique Magazine.
GLOSSARY OF TERMS
This is a glossary of some of the terms used in the diagrams showing the steps involved in making pottery. Working on the wheel is called throwing.
The explanations are simplified, and perhaps inadequate compared to first hand observation.
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This refers to a stage in throwing identified mainly for the purpose of representing an ideal structure. That is, even thickness of the wall, from top to bottom, a good ratio of wall thickness to the other proportions, and the wall coming away at a clear angle to a level base. This is the basic beginning for students and is most evident in the making of a cup or mug, but also in a vase or bottle shape. When making a bowl or plate, the same principles apply, although modified to suit.
Prepare the clay for use by working it into a smooth, and consistent lump, without air pockets. There are various methods, including block, spiral, and sheeps or rams head. A skill similar to kneading dough, although with clay the purpose is to remove air bubbles not to aerate it.
A lump of clay is put onto the center of the wheel. While rotating the clay is grasped between the hands, with a little water. The various forces at work, the turning wheel, the mass of clay, and the potters actions, need to be harmonised to have the clay balanced. The first position is a rounded cone, or hump.
The top of the clay hump is flattened using the side of the palm. Using the fingers and/or the thumb, and placing them at the mid point of the top, and then pushing down towards the base, making a hole. By pulling away from the center, back outwards, the hole is widened and a open form with a base is formed.
An important but often unrecognised step. Pushing the fingers across the base, from the outer edge inwardly to the center, while applying downward pressure. This prevents most problems with the base later cracking during drying. It is best to do it straight after opening the clay, just prior to the main lift. It can be done after the lift but this tends to mishape the lifted form.
Perhaps the most difficult step. On the rotating wheel the clay is naturally tending to spread out wards, and can be guided to rise upwards. What is required mainly is a thinning of the wall. This is achieved by squeezing the wall of the clay. Due to the rotation the squeezing forces the clay upward. There is now a thicker part of the wall above the fingers. This forms a ledge above the fingers. Then the fingers pushing up under the ledge will also lift the clay.
Place the palms of the hands to the side of the opened clay on the walls and push lightly inwards. This controls the tendency of the clay to spread out wards. The slight cone shape stabilizes the clay. More water than usually might be needed. It is often done instinctively in between any activity and when a new throwing step is to begin.
Like cone-in, but more than just guiding the walls inwards, it is used to substantially narrow the opening. It can be done to form a neck or a shoulder. Care needs to be taken to start at the top of the opening and work downwards. Apply mainly a horizontal force, that is push towards the mid point. This does not exclude the need for some downwards force, but be careful not to twist the clay.
Cleaning up the base by trimming away the clay with an under cut where the pot joins the wheel, makes it easier to lift the pot off of the wheel. It also gives a good start, when later it comes to turning the pot. Trimming can be done at any stage in throwing , but always at the end. It also marks the point where the cutting wire will be placed.
The use of a piece of leather, or plastic, smoothes and compresses edges. On the lip of a cup, for example, it serves to also strengthen that edge. It can be used anywhere on a pot to give a smooth finish, without disturbing the shape.
The wire is in the shape of a garrotte, with handles at the end. It can be made with twisted nylon or string, or wire. It is held firmly between the hands and dragged across the wheel to cut the base away from the wheel. This should be done even if the pot is to be left on a bat. A portable flat disc fitted temporarily to the wheel. Cutting makes it easier to remove. There is also a loose ended version, like a whip, which wraps around the clay and is then quickly whipped away.
Using a wooden or metal tool, leatherhard clay can be cut away to make the foot of the pot, or the knob of a lid. Any parts of the pot can be trimmed away. It is a skill similar to wood turning. First cut the surface of the upturned base level and circular. Even if the other parts are not so even this gives a good surface to work on. Place a finger of one hand at the center point of the rotating pot, and rest against it with the tool in the other. This gives stability to the pot while cutting. After turning restore the smooth finish by running a shaping tool over the surface.
Starting from a plug of clay, held in one hand, with the other hand tease out a length of clay, with a pulling action, tapering to the end. If beginning with a large plug of clay, many handles can be pulled from the same plug. The handles are set aside and later attached to the pots. Other methods of making handles include using a similar, but smaller plug of clay, which is immediately attached to the pot, and from there directly pulling a handle.