Surface Decoration for Pottery. engobe – slip used to decorate clay wares, most often applied in the plastic or leather-hard state.
engobe – slip used to decorate clay wares, most often applied in the plastic or
sgraffito – this is a design that can be made by scraping or scratching through a layer of slip that has been applied to a piece of pottery to reach the contrasting color of the clay body beneath.
slip trailing - another decorating method. Slip is applied to the greenware through a tube or nozzle, much like icing a cake.
Motif – a shape or an image within a pattern or alone,
intaglio – decoration below the pottery surface, as in incising, carving, and stamping;
the opposite of relief.
shrinkage - the decrease in the size of clay pottery due to drying and firing. Dry shrinkage is reversible with the return of water, but firing shrinkage is permanent due to chemical and physical changes the clay undergoes when exposed to heat.
chemical water – water that is bound into the molecular structure of clay. It must be evaporated by firing to a minimum 1112˚F. When chemical water is gone, clay becomes ceramic.
maturing temperature – the temperature at which a glaze exhibits it best qualities.
Surface affects caused by temperature variations, uneven shrinkage, and surface quality.
crazing - will occur when the glaze doesn't fit the clay body.The glaze shrinks more than the clay during the cooling causing the glaze to crack like a spider web.
blistering - appearance of broken bubbles found on glazed surfaces of fired ceramics and pottery.
underfiring- firing a piece of pottery below the
temperature required to harden it or
if glazing below the temperature
required to melt it.
crawling – the action by which a glaze
separates from the body during
firing leaving unglazed areas. Crawling occurs when the glaze hasn't properly adhered to the bisqued clay. The most frequent cause is that the glaze was applied to dirty, dusty, or greasy pots. Another cause could be that
the glaze was too thick.
viscosity - the ability of a liquid to flow, the term is used by the pottery worker in relation to molten glazes, glaze suspensions and slips. A stiff molten liquid glaze is one of high viscosity, while a runny molten liquid glaze is one of low viscosity. viscosity Cup - a small cup with hole in bottom used to determine if glaze is the right consistency. A range of 19-23 seconds is normal. If glaze remains in the cup and reading is below or within this range, or if it takes longer than 23 seconds to drain, the glaze is too thick. Add small amounts of water as needed.
modeling – adding clay to the surface of a piece and shaping into a relief.
fettling - the removal or trimming away of excess clay, unwanted blemishes, seams and flash from nearly dry pots prior to glazing and firing.
banding wheel – a small pedestal turntable used to assemble a form,
apply wax, or brush on a band of glaze.
bat – a flat disk that easily detaches from the wheel head; used to transport a pot
without touching it.
shards - pieces of broken pottery.
1-2 coats added over any 05 glaze to create texture
You may choose texturizer to add a variation in the glaze on your coil pottery.