What is Greenware?
Greenware is the term given to clay objects when they have been shaped but have not yet been fired. Firing greenware converts the clay to ceramic. Within the greenware category, there are multiple stages that describe the clay as it is drying: wet, damp, soft leather-hard, leather-hard, stiff leather-hard, dry, and bone dry. At each of these stages, the clay will act in a predictable way as it continues to dry out. Becoming familiar with each of these stages and how clay behaves in each will greatly improve your overall success rate.
Wet: Clay fresh out of the bag. Wet clay is soft and malleable but will hold its shape when molded. Adding additional water to wet clay will result in a slurry or slip.
Damp: The clay at this stage is still workable but has been exposed to air and worked. It will begin to dry out as you work with it. It is easy to go from damp to soft leather hard in a short amount of time if not monitored. Working with pieces that are damp may cause marks on the surface or may distort the piece. Work that is still damp after shaping should be allowed to dry before handling.
Soft leather-hard: At this stage, the clay is in the optimum condition for joining two pieces together or applying slip. This is the best stage to attach on a handle if you’re making something like a teapot or a cup. The clay can be stretched a bit at this stage but small cracks and tears will form if stretched too far. Clay may stick a little to metal tools at this point as well.
Leather-hard: At leather hard, the clay has lost a significant amount of moisture and firmed up a good deal. Pieces at this stage are cool to the touch, and ideal for carving designs, trimming on the wheel, and hard slab construction. Clay at this stage can still be attached but will require a generous amount of scoring and slip to ensure a good strong connection. In the leather-hard stage, the clay can be returned to a workable consistency by adding water.
Stiff leather-hard: At this stage, the clay has lost enough water that the color of the clay will be visibly lighter than when it came out of the bag. At this stage, the piece has begun to become fragile and should be handled as little as possible. Dry brushing slips and smoothing the surface with a damp scrubber can be done at this stage, with care.
Dry: at the dry stage the clay has lost almost all of its moisture and is very fragile. There is still enough water to make the piece cool to the touch. The color of the clay will lighten significantly and attempts to alter the surface will produce dust. You should not work with a piece at this stage unless it's absolutely necessary. If you do, be sure to wear protective equipment so you don't breathe the dust.Bone dry: The final stage of clay drying. At that point, the clay has lost all water except for the water that is bonded at the molecular level. Pieces will be much lighter in color and weight than after forming and are extremely easy to break. Pieces that are bone dry are ready to be bisque-fired. Transporting pieces in the bone dry stage is not advisable because of their fragility.