Ceramic Art

Absorption is used in ceramics as a gauge for vitrification; it is the characteristic of fired clay to absorb water.

Acids are the glass-formers that mix with fluxes (bases) and stabilizers or refractories (known as neutrals).

Agateware is clay products that contain swirling marbleized colors.  The colors are due to surface slip effects, or they may be caused by marbleized colored clays. 

A process that is used to process raw clay.  The process involves floating the powdered clay in an air-stream in order to remove particles containing a higher density.

Mortar or refractory that is cast and becomes durable and strong even though it is damp.  This happens due to a chemical reaction between the clay and water.

Alkaline earths is one segment of high-fire fluxes.  The fluxes contain magnesium, barium, calcium and strontium.  They work best with matt glaze surfaces.

Alkaline Fluxes are feldspars in high-fire; they are boron fluxes in low-fire.

A type of ceramic glaze whose flux is not lead, but an alkali (like soda ash or borax).  Low temperatures are used to fire alkaline glazes and amazing effects can be created.  Persian and Egyptian blues are examples of such effects.  Unfortunately, there are parameters that need to be aware of when using them because alkalis are prone to caking when suspended in a glaze due to their solubility.  

Aluminum silicate is a general category of supplies that are made up of mostly silica and alumina.  It contains raw materials (like feldspar), glaze and fired clay.

Amorphous is a term referring to a solid, homogeneous substance that contains no set melting point or crystalline pattern.  Amorphous substances will crack/separate with conchoidal fracture.  Examples of amorphous substances include lumps of resin or glass.  

Also known as cellar kiln.  Anagama originated from the bank-kiln.  It is a traditional Japanese kiln that contains a long sloping tubular ware chamger along with an extreme below that works as a firebox.  It creates residual-ash effects as well as a large amount of flame-flashing.

Annealing is the method of allowing a heated object to cool down gradually to permit internal shrinkage stress to even out without harming the object.

Applique involves adding low-relief clay forms to slurried, scored leather-hard surfaces for embellishment.

Arch bricks are bricks that contain side faces that are angled and tapered over their widths; when put down together the bricks create a curved arch.  A normal arch brick contains a 4.5 inch thick arch.

Ash slagging is the placement of a lot of deposition of fly-ash on wares’ surfaces, furniture surfaces and the inside of a kiln’s surface within a wooden kiln.

Assisted technology is a type of technology that involves jiggering, ram-pressing and slip-casting; the technology is high-production studio technology that originated from the industry and was then adapted depending upon a particular need.

Atmospheric burner is a gas burner that uses the natural process of gas escaping from the orifice to entrain primary-air; the burner removes the need for a mechanical blower.

Atomic vibration is the continual movement of atoms and molecules that are contained within everything in the universe.  Atomic vibration occurs when heat accelerates the atoms and causes them to break atomic bonds.  This in turn causes a solid to turn into a gas or liquid.

Aventurine is a type of glaze that involves iridescent tiny metallic pieces that are caused from iron crystals residing underneath the surface.

Back burning occurs in burners when the movement of fuel or air leaving the end of the burner is not going as fast than combustion.  This causes the flame to transition down the burner tube to heat the orifice.  And this in turn causes an orange smoky flame and a burner tube that is too hot.

Back-pressure occurs in a fuel kiln due to internal pressure; the internal pressure is due from a correct balance of damper setting and combustion pressure.  The end result of back-pressure is a quicker and cheaper heat system.

A bag wall is a refractory wall that in a few fuel-burning kilns shields the wares from direct contact with the flames and heat.

Ball clay involves deposits of secondary clays that are found in marshy regions.  Ball clay is characterized by high plasticity, a high level of drying shrinkage, a high level of organic contaminates and particles that are very fine and tiny.  Ball clay should be fired off-white or white.

Ball mill is a type of vessel that revolves mechanically; ceramic materials may be positioned with water, as well as high-fired porcelain slugs or flint pebbles.  Ball mill is utilized for grinding glaze and clay materials into small particles.

A banding wheel is a type of wheel that is operated by hand.  The turn-table is capable of doing such things as creating banded decorations and applying wax resist.

A bank kiln is a type of kiln originating from the East Asian kiln.  It involves a tubular kiln chamber that was taken from an earthen bank.  It is a type of kiln that originated before the tube kiln and anagama.

A barrel arch is a type of kiln arch that creates a half circle that includes the start and finish of the arch on a horizontal surface.  No skew bricks are used in a barrel arch.

Basalt body is clay body that contains a sufficient amount of dark clays and/or metallic oxides in order to fire it black or dark brown.

Bases involve the fluxes or melting agents that mix with neutrals and acids.

A Baso valve is a safety valve.  It is used along with a thermocouple sensor probe on the majority of gas kilns.  Baso valves work on a very small amount of electrical current that is made by thermocouple.  No external electrical hookups are usually necessary when one uses a natural-draft kiln that uses a Baso system. In operation, if the pilot is turned off, the thermocouple will cool down and the Baso valve will close – shutting off the gas.

A bat is a firm flat disc of wood, plaster, or plastic that is positioned on the wheel-head.  After the throw is done, the bat is taken off the wheel-head in order to prevent any damage.

Beading glaze is a particular controlled-crawl glaze that was created in order to crack and then crawl under the firing process.  The effect is caused from the high amount of L.O.I in the glaze materials.  The beads are then formed when melting causes isolated beads to develop on the wares’ surfaces.

A bell kiln is a type of kiln that contains a non-movable floor along with a body that can be lifted upward on vertical tracks.  A bell kiln permits one to easily load and remove big objects.

Bentonite is a type of clay that is created from airborne volcanic ash.  The clay must be combined with another type of clay due to its shrinkage being very high.  It is characterized by very fine particles and is very plastic.  If one adds 2-3% to clay it will raise the level of plasticity.  Bentonite is combined with a glaze in order to maintain suspension and enhance the raw glaze adhesion.

Bisque-firing is the beginning kiln firing that involves clay sinters without any vitrifying.  Even though bisque-firing is porous it will not break down in water.

Black-body radiation is the infrared radiation that exits from a material or surface at the point it gets up to red heat.

Black-figure style is a particular style from the late Archaic and early Classical style in ancient Greek ceramics.  It involves the figure that is the focus; red is the color of the background and the figures are in black. 

Blackware firing is bonfire-firing the wares which are covered with dung and sometimes sawdust at high temperatures and then put underneath something like ash or dirt with the intent of capturing the smoke; the result of the process gives the wares a black surface.

Blistering is a glaze defect that involves bubbles on fired glaze surface that frequently burst and create hard craters.  The best way to avoid bubbles during high-firing is to use a short oxidation soak at the finish of the firing process in order to permit the surface defects to right themselves.  One can also use low-firing by elongating the firing process or through soaking the kiln when the time comes for maturation. 

Bloating is a type of firing defect in which blisters are created inside the clay body.  The result of bloating is a series of lumps on top of the surface.  Bloating is due to the expansion of gases inside the clay due to too much early reduction (which causes carbon coring), too much fast bisque firing, and extending the firing process for too long.  

Blunge is the method of combining a glaze or slip with an impeller mixer is that motorized.

A blunger is an impeller mixer that is motorized that is utilized to get a casting slip or clay slurry ready.  It is positioned on a clamp or bracket to permit a slip to remain blunging for a long amount of time.

A body reduction is an amount of time in which reduction atmosphere is created between cone 012 and 08 to allow iron color and speckles in clay body; it is used in particular in high-fired stoneware.

Bone China is a type of clear porcelain that contains bone-ash.

Bone dry in ceramics means that something is very dry and brittle.  It is necessary that clay is bone dry before one fires it.

A hand-building technique employed to create pots.  Clay plastic "snakes" are formed, pushed and pinched to combine them into a pot. Sometimes the artist leaves the coil appearance to achieve a particular affect.  Ceramics created with coil building depend largely on the artist's hand to create the object's form vs. using a potters wheel or mold.  The coils themselves may be defined or smooth based upon the texture of the object or the intent of the artist.   

A factory that creates metal castings.  Metals, such as aluminum or iron, are cast into shapes by pouring melted metal into molds and then taking off the mold or casting once the metal has solidified. 

Pyrometric devices utilized to asses the conditions of heat during the firing of ceramic materials.  The cones give a visual portrayal of when the items have attained a level of maturity (related to temperature and time).  They are made out of clay and glaze material.