74 terms · plain language
the pottery glossary.
Every craft hides behind its words. Here they all are, defined the way we would across the bench, from anagama to wood firing. Terms you will meet in the guides link straight back here.
a
- anagama
- A single-chamber wood-fired tunnel kiln of japanese origin, stoked continuously for days. Ash and flame travel the chamber and glaze the work naturally. The kiln type this studio's firing romance descends from.
b
- banding wheel
- A hand-spun turntable used for decorating and hand building. A wheel with no motor and no ambitions, and every studio needs two.
- bat
- A removable disc (timber, plaster, plastic) attached to the wheel head so thrown work can be lifted off without touching it.
- bisque
- Pottery after its first, lower-temperature firing: hard enough to handle, porous enough to absorb glaze. Also the name of that firing (bisque firing), usually around cone 06.
- bone dry
- Clay that has dried as far as air can take it, pale and fragile as biscuit. The state work must reach before its first firing; any remaining moisture becomes steam in the kiln.
- burnishing
- Polishing leather-hard or bone-dry clay with a smooth stone or spoon until it shines without glaze. Ancient, slow, and lovely on unglazed forms.
c
- celadon
- A family of pale green to blue-grey glazes coloured by small amounts of iron fired in reduction. Softly translucent, pools beautifully in carving. The only glaze on our moon jar.
- centering
- Forcing a lump of clay into perfect rotational symmetry on the spinning wheel, so it stands still in the hands while moving. The gatekeeper skill of throwing.see also: throwing · coning
- chattering
- A rhythmic decorative texture cut by a springy tool bouncing against leather-hard clay on the wheel. Deliberate on our carved pieces; accidental during trimming when the tool is dull or the angle wrong.
- clay body
- A blended recipe of clays and minerals designed to throw, dry, and fire predictably at a stated temperature. What the bag label describes.see also: stoneware · earthenware · porcelain
- coiling
- Hand building by stacking and blending rolled ropes of clay. One of the oldest making methods on earth and still one of the best for large forms.
- cone
- A small engineered pyramid that bends when a precise amount of heatwork has occurred, measuring what clay actually experiences rather than bare temperature. Cone 10, this studio's endpoint, is roughly 1300 C.see also: heatwork · kiln
- coning
- Squeezing centred clay up into a cone and pressing it back down, repeated to align particles and finish centering. The wheel's version of kneading.
- crawling
- A glaze defect where the melt retreats into islands, leaving bare clay. Usually dust or oil under the glaze, or a coat applied too thickly.
d
- deflocculant
- An additive that makes a clay slip fluid without extra water. The chemistry trick behind slip casting.
- dunting
- Cracking caused by stress during kiln cooling, classically from cooling too fast through quartz inversion at 573 C. The heartbreak of impatient kiln-openers.
e
- earthenware
- Low-fired clay (roughly cone 06 to 02) that stays porous unless glazed. Warm colours, long history, chips more easily than stoneware. Terracotta is its most famous member.
- engobe
- A coloured clay slip applied for decoration, sitting somewhere between slip and glaze in character.
f
- faceting
- Cutting flat planes into a thrown form with a wire or blade, turning a round pot into geometry.
- fettling
- Cleaning up seams, edges, and rough spots on unfired work. The tidying stage of making.
- firing
- Heating clay until it permanently becomes ceramic. Bisque firing hardens; glaze firing matures body and melts glaze. The step where proposal becomes decision.see also: cone · kiln · vitrification
- flashing
- Blushes of colour on bare clay where flame and ash touched it in an atmospheric firing. Unrepeatable by design; the wood kiln's signature.
- flux
- The ingredient family in glazes and clay bodies that lowers melting temperature so everything fuses at kiln heat. The persuader in the recipe.
- foot ring
- The trimmed ring a pot stands on, usually left unglazed. Where the maker's hand and judgement are most visible; collectors turn pieces over first.see also: trimming
- frit
- Glaze materials pre-melted to glass and reground, taming solubility and toxicity. Chemistry made safe to handle.
g
- glaze
- Ground glass and minerals suspended in water, applied to bisque ware and melted in the kiln into a permanent surface. Silica for glass, alumina for stiffness, flux for melting, oxides for colour.see also: flux · oxide · glaze fit
- glaze fit
- How closely a glaze's shrinkage matches its clay body's. Poor fit produces crazing (glaze too tight) or shivering (glaze too loose).
- greenware
- Unfired clay work in any state from wet to bone dry. The piece at its most fragile and most honest, and the word this studio's whole landing manifesto borrows.
- grog
- Fired clay ground up and added back into a body for strength and stability. Makes clay 'toothy', reduces warping, adds texture.
h
- hakeme
- Slip applied with a coarse brush so the strokes stay visible. Korean in origin, loved everywhere.
- hand building
- Making without a wheel: pinching, coiling, slab work. A complete craft, not a lesser one.see also: coiling · slab building · pinch pot
- heatwork
- The combined effect of temperature and time on clay and glaze. What cones measure and pyrometers cannot.
k
- kiln
- The furnace that turns clay to ceramic: electric for clean predictability, gas or wood for atmosphere and chance. This studio's is fired with wood and patience.
- kiln wash
- A protective coating painted on kiln shelves so glaze accidents can be chipped off. The insurance layer under every firing.
- kintsugi
- The japanese repair tradition of joining broken ceramics with lacquer and gold, making the break part of the piece's story. Some pieces are better with a gold seam.
- kurinuki
- Carving a vessel from a solid block of clay by hollowing it out. Slow, sculptural, and meditative.
l
m
- majolica
- The technique of painting colour onto an unfired white glaze surface. Italy's gift to bright pottery.
- maker's mark
- The stamp or signature a potter presses into work, usually near the foot. Provenance in three square centimetres.see also: foot ring
- maturity
- The firing point where a clay body reaches full density and a glaze fully melts. Underfired work never gets there; overfired work slumps past it.
- mishima
- Inlaying contrasting slip into carved lines, then scraping back to reveal crisp drawing. Patience rewarded.
- moon jar
- A large, softly imperfect spherical jar, thrown in two halves and joined, from the korean tradition. Ours wears the studio's only glaze.
o
- opening
- Pressing down into centred clay and widening the floor: the first move of throwing after centering.see also: centering · throwing
- oxidation
- Firing with ample oxygen, as in electric kilns. Clean, bright, predictable colour response.see also: reduction
- oxide
- Metal compounds that colour ceramics: iron for ambers and speckle, cobalt for blue, copper for green (or red in reduction), rutile for break and movement.
p
- pinch pot
- A vessel formed by pinching a ball of clay between thumb and fingers. The first pot almost everyone makes, and a form masters return to.
- porcelain
- A white, fine, high-fired body that becomes translucent when thin. Beautiful, demanding, and famous for punishing beginners.
- pulling
- Two meanings: raising a wall between fingers on the wheel, and stroking a handle to shape from a carrot of clay. Both are the same gesture at different angles.
q
- quartz inversion
- At 573 C, crystalline silica in clay snaps between forms with a small size change, going up and coming down. Firing schedules slow down here; rushing it cracks pots.
r
- raku
- A firing method where glowing work is pulled from the kiln around 1000 C and often post-fired in combustibles. Crackle, smoke, drama. Decorative only, never for food.
- reclaim
- Failed and trimmed clay slaked in water, dried on plaster, and wedged back to life. Pottery's built-in recycling; the reclaim bin is where unearned pots go.
- reduction
- Firing with restricted oxygen so the flame strips it from oxides in clay and glaze, transforming colours: copper reds, grey-green celadons, blooming iron speckle.see also: oxidation · celadon
- resist
- Wax, latex, or paper applied to block glaze or slip from a surface. How feet stay clean and patterns stay sharp.see also: foot ring
- rib
- A hand-held profile of timber, metal, or rubber used to shape, smooth, and compress clay on and off the wheel. The most personal tool a potter owns.
s
- s-crack
- A spiral crack in the base of thrown work, appearing during drying, caused by uncompressed clay at opening. Prevented in ten seconds; unfixable afterwards.
- saggar
- A protective box enclosing work inside a kiln, either shielding it from the atmosphere or trapping fuming materials against it.
- sgraffito
- Scratching a drawing through a layer of coloured slip to expose the clay beneath. Pottery's woodcut.
- shivering
- Glaze flaking off in slivers because it shrank less than its body: the dangerous opposite of crazing. Retires a piece from the table immediately.
- slab building
- Hand building from rolled sheets of clay, cut and joined like fabric. The route to boxes, platters, and architecture.
- slip
- Liquid clay. Used as glue for joining, as decoration under glaze, and (deflocculated) for casting.see also: engobe · slip casting
- slip casting
- Pouring liquid clay into plaster moulds to form identical pieces. A legitimate craft in its own right, and the honest answer to how factory 'handmade' ware is actually made.
- speckle
- Dark freckles from iron particles burning through glaze. In our clay it is the signature underfoot; in bodies it is bought by the bag.
- stoneware
- Clay fired high enough (roughly cone 5 to 10) to vitrify dense and tough. The workhorse of functional pottery and the body under every piece in this studio.see also: vitrification · clay body
t
- tenmoku
- A deep iron-saturated glaze firing black to rust, breaking amber where thin. A thousand years old and still not improved on.
- throwing
- Forming vessels from spinning clay on the wheel. From an old english word for turning; nothing is thrown anywhere, except occasionally in frustration.see also: centering · opening · pulling
- trimming
- Cutting excess clay from leather-hard work on the wheel and carving the foot ring. Where heavy pots become good pots.see also: foot ring · leather hard
u
- underglaze
- Commercial colour applied before (or under) a clear glaze. How illustration gets onto pots and survives the fire.
v
- vitrification
- The point in firing where clay particles fuse glassy and dense, closing porosity. What makes stoneware waterproof and dishwasher-proof without depending on glaze.