All Pre- and Post-processing of Claybot objects follow standard clay/ceramic practice. After printing you can still shape and work the clay like any other conventionally produced work. The state of the body evolves as the greenware piece dries prior to placing it in a bisque firing.
As an object air-dries it moves through these states:
- Wet (newly produced) and not workable
- Soft (damp surfaces)
- Medium (inner damp surfaces – leather-hard outside)
It is important to remember that just because one section of your piece is in one state does not mean internal or wall intersections are in the same state. The time it takes for drying to occur varies depending on design and environmental conditions. But in low humidity, ambient temperatures 20-30°C, this will take a minimum of 2-4 days and could be as much as 7-10. Depending on your project, you might choose to slow this further by wrapping all or parts of your object in polythene to prevent drying out in advance of adjacent sections.
At various points in the greenware drying cycle it may become judicious to imbue decoration to your object. A summary of the main techniques is provided below.
Subtractive Decoration involves removing clay from the surface of your 3d-printed object. This includes:
Carving – which may be done at any stage from soft to bone-dry. Although carving tends to be most satisfying when the clay is medium to leather-hard, gestural “smeared” effects are best introduced in very soft clay.
Piercing openingsinto a clay object may be preferable to attempting to print and support them in the wet state. Piercing is normally done at medium leather-hard stage with a hole-puncher or razor knife. However, it may also be accomplished at the leather-hard or bone-dry stage with an ordinary drill bit.
Incising usually refers to shallow carved lines or patterns using a dull-pointed dowel, or a dull pencil. Too sharp and you are effectively inviting cracks to form!
Additive Decoration is where clay is added to the existing surface of a clay form. In general, you should score the object surface and slurry all add-ons, except in sprigging. If the add-on itself is soft plastic clay, score and slip/slurry only the attachment point on the main form. If the add-on is leather-hard, score and slurry both surfaces.
Appliqué generally refers to preformed flat pressed or carved clay decorations added onto the surface of a piece.
Sprigging is pressing either small coils and/or balls of clay onto the surface. A thin coat of slip (without scoring) is adequate and is a nice way to introduce coloured contrast.
Modelled decoration includes a variety of methods when clay is added and then smoothed into the surface to create raised ridges, strips and pads. Sculptural manipulation with fingers and hands is then accomplished.