Abrasion The process of grinding away the top surface of a piece of flashed glass. A grinding wheel or burr may be used.

Acetates Scaled down treatments of windows of stained glass done with special paints on heavy plastic to get a "see through" effect.

Aciding Process of etching the ‘flash’ off antique glass

Annealing Chamber That part of the kiln which is used to cool down fired glass

Antique glass Handmade, mouth-blown coloured or clear glass that is made by the old glassblowing methods. The glass is blown into cylinders and the cylinders cut and flattened into sheets. Used mostly in production of stained glass

Asphaltus varnish A liquid preparation used to protect the surface of the glass from hydrofluoric acid.

Banding Action of fixing copper wire ties to panels of glass

Blender Badger-hair brush used for blending vitreous paints on the surface of glass.

Breaking the score Separating a piece of glass into planned sections along a marked line.

Breaking and entering It is more difficult for a burglar to get into a home through a stained-glass window than through a normal window.

Camel hair An old name for various soft-hair brushes—not actual camel’s hair.

Cartoon Working painting or drawing, usually full-sized of stained glass containing all cut lines and possibly all paint lines.

Cathedral glass Machine—made, transparent stained glass. Uniform in thickness; about 3mm

Composition The overall design of a finished piece containing the proper balance of color and linear flow.

Copperfoiling Wrapping the edges of glass with adhesive backed copper foil in preparation to soldering them together. This technique was developed seperately by Louis Comfort Tiffany and John Le Farge and used to great effect by both studios. Give your eyes a treat and do a search on them.

Cut line A line indicating the borders of the cut edges of glass in a cartoon.

Cylinder One of the steps in the production of antique glass sheets

Dalle-de-Verre French term for very thick glass Broken pieces of dalles, or chunks of glass bonded together with epoxy or cement to produce a flat panel, also may be copper foiled into windows or lamps to give a faceted effect.

Enamel Opaque vitreous color applied to glass. Changes to a transparent color in the fire.

English stippler Round, 4"-long horsehair or bristle-hair brush used for stippling paint on the surface of glass.

Epoxy Clear, fast—drying glues for joining glass to glass.

Etching This process is done with hydrofluoric acid, the only acid that attacks glass. Removing the surface color of flashed antique glass either fully to expose the body colour of the glasss or partially to lighten the flashed colour. The purpose of etching is to save cutting and leading of tiny pieces. Etching can be done only on flashed glass.

Favrile A word coined by Tiffany to describe his glass.

Flashed glass A sheet of glass where one color is laid on top of another. Any color may be flashed on top of another provided the two are not mutually exclusive of light. Such glass is used extensively in etching, but it can be used as is for the particular hue it presents.

Fusing The art of adhering glass to other glass surfaces or melting one glass directly into another. The heat necessary for this is best applied in a kiln, though a torch may be used with very small pieces.

Gamboge Yellow pigment. An ingredient of silver stain

Glass bending Sagging or draping glass over a mold, then heating the glass blank in a kiln until it either sags into or drapes over the mold.

Glass globs Thick, rounded pieces of stained glass of varied colors and sizes used as glass ‘jewels" to enhance a design.

Glass jewels These may be faceted, hollowbacked, reflective, or bulls—eyed. Unlike globs, which are allowed to assume their own shape, or chunks, which are hacked off a dalle at random, jewels are cast in a steel mold and then polished.

Glass thickness Anywhere from 3mm in machine—made (cathedral) glass to nearly 12mm in certain heavy antique glass. Thickness in antique glass may not be uniform within the same sheet. This is liable to cause a rocking of the glass on the cutting surface, which must be compensated for by the worker.

Granite-backed glass A form of textured glass with one side roughened

Grisaille A process developed in the thirteenth century for windows having the bulk of the glass white or gray with extensive leading. The most famous example in the UK is the Five Sisters window at York Cathedral.

Grozer Tool used in shaping and cutting glass (nowdays normally pliers)

Grozing Nibbling away the small pinpoints and chips of glass along a cut surface using a finetooth pliers especially made for the purpose.

Gum Arabic A water-soluble gum used for mixing vitreous paints.

Hammered glass A type of textured cathedral glass with multiple small indentations.

Hydrofluoric acid The only material that attacks silica (a basic constituent of glass). It is used for etching.

Joint The area where one lead line meets another. Such joints usually butt one against another.

Kiln Basically an oven made of firebrick or ceramic fibre. Kilns can be electric or gas heated, in the old days would have been coal or wood-burning.

Knapping The process of faceting slab glass by chipping away at the edges with the slab glass hammer. (see dalle de verre)

Lathekin Tool made of wood or nylon for manipulating lead cames

Lead came Extruded lead channel, usually H-section, used to hold together the individual pieces of glass in a stained-glass window.

Leaded glass Glass held together by lead cames.

Lead line A term used in window design to indicate the placement of the lead came in the actual panel.

Leading Assembling a work of stained glass where lead came is the holding material.

Matting Applying a translucent coat of vitreous paint to the surface of a large area of glass.

Mold High-temperature firing shapes into which glass can be slumped or over which it can be bent or folded.

Mold release A substance applied to the surface of a mold to prevent the glass from sticking to it at high temperature. Powdered mica,or graphite may be employed.

Muller Small hand mill made of glass or marble for grinding paint powder very finely on a ground glass pallette

Mullion Vertical inner division of window used in Gothic architecture to uphold the inner tracery of windows. Wooden verticals used in the studio to represent the above and to support easels

Oil of Spike Lavender (see vehicle)

Opalescent glass Nontransparent glass; the colors are seen by reflected light.

Oxidation The tough, outer coat on lead came that must be wirebrushed before soldering.

Pattern A paper, card or thin sheet metal template from which the glass pieces are cut.

Ponce bag A piece of tied-up rag with whiting inside used as a stencil.

Pot metal The medieval name for the molten glass "batch." It was heated in a large pot and metallic oxides were added for color.

Reamies Sheets of antique glass containing faint and delicate streaks of color.

Reinforcing rods Galvanized steel rods used to span a window to prevent it from bowing (see saddle bars).

Resist material Used to protect areas of the glass to be left unchanged, as in etching, silkscreening and sandblasting. Asphaltum and beeswax are resist materials.

Rolled edges Usually found only on antique sheets where the cylinder of glass was cut. This has smoothed over from the oven and bulged somewhat from the surface. It must be cut away before the sheet can be worked.

Saddle bars Supporting metal bars attached to reinforce stained-glass windows.

Sandblasting Another form of glass abrading.

Score The line imposed by a glass cutter or diamond upon the surface of a piece of glass. The fracture line weakens the glass along its length.

Scrubs Cut-down bristle-hair brushes used for removing matting paint.

Semi-opal antiques Usually opal (white) or gray opaque pigment fused to the surface of clear or colored antique glass.

Semiantique glass Machine—made glass with little movement or texture but with brilliant tones.

Silkscreening A printing method of applying paint to glass.

Silver stain Silver nitrate mixed with gamboge gum. When fired it stains the surface of the glass anywhere from a transparent yellow colour to a deep orange.

Springline The horizontal line below which the upright sides end and above which the curve of the arch begins

Squeegee oil Oil used to prepare glass stainers’ colors and transparent glass colors (enamels) for silkscreening.

Stenciling A method of producing a repeated pattern on glass.

Stippling Method of painting using the butt end of the brush, usually a badger, to let in minute points of light through the paint

Streakies Glass sheets with streaks of color running through them. Colors may be many and varied against a background of yet another color, either opalescent or antique.

Striations Marks on antique glass, like scratches, making the glass more brilliant and crystalline in effect

Tapping One of the techniques of breaking out a score. A ball—ended glass cutter is used, though the heavy end of a regular cutter is also effective. Glass must always be tapped from the bottom.

Template Shape, cut out of tracing paper, paper, or thin card corresponding to the exact size of a piece of glass required

Tinning Soldering completely over the surface of another metal either to stiffen it or to allow its color to be changed.

Tints Lightly colored hues and tones of stained glass.

Tracer A special brush used in painting on glass.

Tracing Painting on glass with lines.

Tracery Shapes in the head of a Gothic window

Vehicle Medium (Venice turpentine, glycerin, gum arabic) used to increase the flow and the bind of glass stainers’ colors.

Vitreous paint A mixture of ground glass and a pigment of metallic oxides used for painting on glass. It has to be fired in for permanent adhesion.

Whiting (calcium carbonate) Ground chalk used to prevent silver stain from penetrating firing trays in the kiln and to keep the firing surface smooth.