Three clay-body categories, five primary forming techniques, two kiln atmospheres, and the pyrometric cone chart that ties them together. Every figure on this page links to its source — Orton Ceramic, Digitalfire, Wikipedia, or a named studio publication. No fabricated stats.
The three principal clay-body categories are distinguished primarily by maturation temperature and resulting density. Edge cases exist (cone 6 porcelains, cone 6 earthenwares), but the table below reflects the conventional ranges used by suppliers and studios.
Porous · bright colour · beginner-friendly
A clay fired at low temperatures. Earthenwares do not vitrify at these temperatures — particle bonding is by sintering, and the body remains porous unless sealed by glaze.[Digitalfire]
Dense · durable · the studio workhorse
Stoneware bodies vitrify in the mid-to-high fire range, becoming dense and non-porous once mature. The most adaptable category for functional ware.
White · translucent · refined
Porcelain matures at the highest temperatures, developing a white, fine-grained, often translucent body. Less forgiving than stoneware — softer when wet, more prone to warping in drying and firing.
Pottery forming techniques are conventionally grouped into three families: hand-building (pinching, coiling, slab), wheel throwing, and slip casting.[Wikipedia] Industrial methods (jiggering, ram pressing, injection moulding) are out of scope for studio practice.
The oldest and simplest technique: a ball of clay is opened with the thumb and walls are gradually pinched outward.[Wikipedia] Best suited to palm-sized vessels — pots, bowls, cups — where wall thickness can be controlled by feel.
Construction by winding long cylindrical rolls of clay on top of one another, allowing each layer to firm up before the next.[Wikipedia] Permits greater shape variety than throwing — coils can build any silhouette including extreme curves.
Flat sheets of clay are rolled out (slab roller or rolling pin), cut to shape, and joined.[Artsper] The only handbuilding technique that naturally produces flat planes — ideal for boxes, tiles, and angular sculpture.
A lump of clay is centred on a spinning wheel and shaped by the potter's hands as it rotates.[Wikipedia] The fastest path to symmetrical rotational forms (cylinders, bowls, plates) and the most iconic ceramic technique. Steep learning curve compared to handbuilding.
Liquid clay (slip) is poured into a porous plaster mould, which absorbs water and builds a clay layer against the mould wall. Excess slip is poured off, leaving a hollow shell that conforms exactly to the cavity.[Wikipedia] The only technique that produces identical copies and supports undercuts / square forms / very thin walls.
These are recommendations based on the trade-offs in the data above — framed as site opinion, not universal fact. Different studios teach differently.
Hand-building needs only clay and your hands. The Tableware Curator and Terra & Ember both name pinching as the entry point and coiling as the next step for taller forms.[Tableware Curator, Terra & Ember] Build vessels you can hold in two hands first.
Most contemporary potters fire mid-range stoneware in electric kilns. The cone 5–6 range (1180–1230°C) vitrifies stoneware bodies, glazes mature well, and the firing is cheaper than cone 10.[Glazy]
Celadons, tenmokus, shinos, and copper reds are families of glaze that emerge specifically in reduction firing. Iron and copper colourants behave fundamentally differently when starved of oxygen.[Digitalfire] Requires a fuel kiln (gas or wood), not electric.
Square vessels, asymmetric containers, figurative sculpture with undercuts, very thin walls — none of these are throwable.[Trove] Tooling cost (plaster, mould-making) is real but pays off in repeatable output.
The kiln's oxygen environment fundamentally changes how iron, copper, and other colourants behave. Atmosphere is the second axis of firing — temperature is only the first.
The kiln burns clean — complete combustion, plentiful oxygen. Electric kilns are inherently oxidising. Iron oxide stays as Fe2O3: refractory, poorly fluxed, producing browns and yellows.[Digitalfire] Glaze palette is broader and more vivid; colours are predictable.
The damper closes, the kiln burns rich, and combustion becomes incomplete. Carbon-monoxide-rich atmosphere strips oxygen from glaze components: iron converts from Fe2O3 to FeO and acts as a flux, copper goes from green to red.[Digitalfire] The signature firing for celadons, tenmokus, shinos, copper reds.
A subset of reduction. Burning wood deposits fly ash on the ware; at high temperature the ash melts to form a natural glaze. Wood-fired surfaces show flame-paths and ash gradients impossible to reproduce in electric or gas kilns.[Trove]
Most of the major historical glaze families are variations on two colourants: iron oxide (celadons through tenmokus) and copper oxide (oribe and copper reds). Behaviour depends on percentage and atmosphere.
Transparent green to blue-green glaze coloured by small amounts of iron oxide (typically 0.5–2%) fired in reduction.[Garland, Digitalfire] Traditionally fired around cone 10 (~1300°C); cone 6 versions exist but purists distinguish them. Originated in Chinese kilns from the Shang dynasty onwards; mastered at Longquan in the Northern Song.[Ippodo]
Iron-saturated glaze that fires glossy black to deep brown.[CMW] Subfamilies include hare's-fur (vertical iron streaks), oil-spot / yuteki (silver iridescent spots from iron crystals, often fired in oxidation), and yohen (iridescent multicolour from controlled crystal growth). Classic versions are cone 10 reduction.
Originally Japanese (Mino, late 16th c.). A high-feldspar glaze fired in reduction that traps carbon to produce orange-to-grey surfaces with characteristic crawl and pinhole texture.[Garland]
Copper-bearing glaze, vivid green in oxidation. Named after the Mino ware style popularised in 17th-century Gifu Prefecture.[Musubi Kiln]
The same copper colourant as Oribe, but fired in reduction — produces a deep red instead of green. Famously difficult to fire consistently. Reduction strips oxygen from copper, shifting it to the elemental form responsible for the red.[Digitalfire]
Wood-ash-based glaze, the historical root of East Asian glaze traditions. Either deposited naturally during wood firing or applied as a slip. Behaviour depends heavily on the species and combustion temperature of the source wood.
Pyrometric cones measure heat-work — the combined effect of time and temperature — not temperature alone.[Orton] The temperatures below are end-points for large self-supporting cones at the standard heating rate of 108°F/hr (60°C/hr) in the final 90–120 minutes; faster firing pushes the equivalent temperature higher.
| Cone | Temperature | Typical use |
|---|---|---|
| Cone 022 | ~600°C / 1112°F | Lowest end of pottery range — lustre / china paint |
| Cone 06 | ~999°C / 1830°F | Low bisque, low-fire glaze |
| Cone 04 | ~1060°C / 1940°F | Earthenware maturation, low-fire glaze[Glazy] |
| Cone 1 | ~1137°C / 2079°F | Edge of low-fire / start of mid-fire |
| Cone 5 | ~1186°C / 2167°F | Mid-fire stoneware (electric kiln sweet spot)[Glazy] |
| Cone 6 | ~1222°C / 2232°F | Mid-fire stoneware, most popular contemporary range |
| Cone 8 | ~1263°C / 2305°F | Lower porcelain, mid-high stoneware |
| Cone 9 | ~1280°C / 2336°F | High-fire stoneware, lower porcelain |
| Cone 10 | ~1305°C / 2381°F | Classic high-fire range — reduction celadons, tenmokus, copper reds[Glazy, Kiln Arts] |
| Cone 11–12 | ~1315–1335°C | Hard porcelain |
The full studio workflow, in order. Each stage has its own failure modes, and a piece can be lost at any of them.
Kneading the clay to remove air pockets and homogenise moisture. Air pockets remaining in the clay can expand explosively in the kiln. Wedging also aligns the clay particles for throwing.
Pinching, coiling, slab, throwing, or casting (see section above). Output is a "green" piece — wet clay holding its shape but very fragile.
The piece dries gradually to leather-hard (firm but still cool to the touch, can be carved or trimmed) and then to bone-dry (room-temperature, very fragile, ready for firing). Rushing drying causes cracks.
At leather-hard, the foot ring is trimmed, surfaces refined, handles attached (with slip-and-score), decoration carved or impressed. Last chance to fix shape.
First firing, typically to cone 08–04 (~950–1060°C). Drives off chemically bound water, burns out organics, converts soft clay to a hard but still porous body suitable for glazing.[Bellevue College]
Glaze applied to bisque ware by dipping, pouring, brushing, or spraying. Application thickness changes how the glaze fires — tenmoku and celadon both require deliberate thickness control.[CMW]
Second firing, to the maturation temperature of the clay body and glaze: cone 04 for earthenware, cone 6 for mid-fire stoneware, cone 10 for high-fire stoneware / porcelain. Atmosphere (oxidation vs reduction) is chosen here.
Kiln must cool slowly (usually overnight) to prevent dunting (cracks from thermal shock). Pyrometric cones inside the kiln are inspected to confirm heat-work actually delivered.[Orton]