The glossary is designed to assist you in finding and understanding all of the various terms associated with glass, ceramics, metal, clay, enameling, and more! We hope you will find this a useful resource as we have emptied our brains and have nothing left to share with you!

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DALLES — Thick (usually 1") slabs of cathedral glass.
DALLE DE VERRE — A technique in which dalles are broken into pieces with a carbon hammer and set in an epoxy base to adhere them in a decorative design. Dependent on large scale for best appearance, they are primarily used in architectural applications such as church walls.
DAY TANK — A glass melting furnace that is designed to operate on a 24-hour cycle. The batch is added to an empty furnace at a rate that allows it to melt properly, until the furnace chamber is full. Then, after suitable "cookout" has occurred, the molten glass is used to make product. When the furnace is empty, the cycle is repeated
DEVITRIFICATION — The state of change of the molecular structure of glass to become “unlike glass.” This occurs in the temperature zone between 1300F - 1425F. Glass that remains in this zone for too long of a period, will develop a surface coating or growth that appears as a scum, dull or matte finish on the surface. The glass undergoes a surface change in appearance and texture from glassy to cloudy.
DEVITRIFICATION SPRAY — This spray is applied to the surface of glass before firing to avoid devitrification and helps to give the piece a shiny surface.
DEFLOCCULATE — To disperse the particles in a clay slip so that less water is required to make the slip fluid.
DIAMOND HAND PADS — The most popular type of polishing pads. A type of hand finishing tool that is used when the circumstances call for polishing by hand.
DICHROIC COATING/GLASS — Commonly used term to describe glasses that have been coated with one or more ultra-thin crystalline layers of transparent metal oxides designed to enhance reflections at specific wave lengths of light. The process occurs in a vacuum chamber at elevated temperatures. The resulting effects are striking and brilliant color reflections when viewed from different angles. Dichroic Glass is very unique in that it has both a transmitted color and a reflective color that is completely different.
DIP MOLD/OPTIC MOLD — A cylindrical, tapered mold with an internal pattern. The mold is open at the top so that molten glass can be dipped into it and then manipulated.
DRAPERY GLASS — Glass sheets with multiple dramatic folds, likened to those in hanging drapes.
DUNTING — Cracks, which occur on pottery during the heating or cooling cycle of the firing. They are usually caused by the silica inversion.1063oF (Alpha to Beta phase) or the Crystobalite inversion at 428oF in both cases there is an expansion and contraction of around 2-3% in the heating and cooling cycles.
DUST MASK — Fits over your nose and mouth to protect you from breathing in harmful dust, or glass particles.
EARTHENWARE — A low fired form of pottery or objects (below 1100oC, 2012oF) made from clay, which is porous and permeable. The clay can be any color although iron red is usually associated with Terracotta. The low temperature vastly expands the range of glaze colors available these are often alkaline or lead based. Beginning potters often work with earthenware because its blend of materials - quartz, kaolin, ball clay, and feldspar - is inexpensive and easier to work with than finer clays.
ELEMENTS — Wires inside the kiln that produce heat. They are usually made from a metal alloy called Kanthal. Also made from iron chromium or nickel chromium.
ENAMELS — A highly pigmented form of low temperature glaze. Enamels which works at a low temperature. Enamels are also made into paints made from finely ground glass and pigments that can be used to add color. Then they are fired on to the glass or metals.
ENAMELED DECORATION — A Decorative glass technique commonly used in Victorian art glass, hand painting glass decorative technique using white or colored enamel paints applied on a finished glass piece and re fired to bake the enamel finish.
ENAMELING KILN — Enameling kilns are small tabletop kilns used for glaze testing or decorating jewelry, glass, metal, or pottery. Enameling is the application of a hard and glossy decorative or protective coating, usually translucent glass, that fuses with its substrate when fired in an enameling kiln.
ENGRAVING — A pattern or design that is cut into a glass surface, usually with a diamond-surfaced wheel on a lathe or bench grinder.
ENGLOBE — A colored clay slip applied to greenware or leather-hard clay bodies, usually before bisque firing, in order to add texture, color, and background or to prepare the surface for additional decorating.
ETCHED MOLD — Glass mold technique with pattern etched into the surface, achieving very fine detail in pressed glass.
ETCHING — Patterns or designs cut into glass either by acid etching or needle etching techniques.
EXPANSION COEFFICIENT — A numerical designator assigned to a glass to describe its Coefficient of Expansion.