Glass Terminology

June 16, 2017 Glass Terminology0
Acid Stamping :
The process of acid etching a trademark or signature into glass after it has been annealed, using a device that resembles a rubber stamp.
Alabastron :
(Greek) or Alabastrum (Latin): A small bottle or flask for perfume or toilet oil, usually with a flattened rim, a narrow neck, a cylindrical body, and two small handles.
Alarm Glass :
A particular form of laminated glass, used for security purposes. The glass has 0.1 mm. wires embedded in the interlayer. The wires form an electrical circuit which, if broken in the event of the glass sheet being smashed, sets off an alarm.
Ale Glass :
A type of English drinking glass for ale or beer. Ale glasses, first made in the 17th century, have a tall and conical cup, a stem, and a foot. They may be enameled, engraved, or gilded with representations of hops or barley.
Amen Glass :
A rare type of English wine glass with a drawn stem.
Amphora :
A jar with two handles.
Ancient glass :
Generally used to mean all pre-Roman and ancient Roman glasses.
Andalusite (Al2SiO5) :
A neosilicate mineral, usually found in metamorphic rocks and used in the manufacture of refractories.
Annealing :
In the manufacturing of float glass, it is the process of controlled cooling done in a lehr to prevent residual stresses in the glass. Re-annealing is the process of removing objectionable stresses in glass by re-heating to a suitable temperature followed by a controlled cooling.
Annealing Lehr :
An on-line, controlled heating/cooling apparatus located after the tin bath & before the cooling conveyor of a float glass production line. It’s purpose is to relieve induced stress from the flat glass product to allow normal cold end processing.
Antenna Glass :
Automotive glass where thin antenna wire for radio reception has been embedded in the intermediate layer of laminated glass or where a conductive silver thread has been fused to the inner surface of the vehicle’s glazing.
Apse :
The semi-circular termination of the east end of the chancel or chapel.
Argon :
It is a nontoxic and inert gas. It is filled inside sealed units of insulating glass to improve their insulating capacity.
At-the-Fire :
The process of reheating a blown glass object at the glory hole during manufacture, to permit further inflation and/or manipulation with tools.
Autoclave :
A vessel that employs high temperature & heat. In the glass industry, used to produce bond between glass & PVB or urethane sheet, creating a laminated glass product.
Azs Refractories :
Refractory blocks or tiles in varying proportions of alumina-zirconia-silica; initially used for areas where corrosion resistance was important but now used in most parts of the furnace.
Badging :
A method for etching glass in which an acid paste is applied to the surface of the glass with a rubber stamp.
Baptistery :
A separate room or building of a church containing the font.
Bar (Barring) :
A single piece of glass formed by fusing several canes or rods. A bar can be cut into numerous slices, all with the same design, to be used as inlays or appliqués, or in making mosaic glass.
Bat :
Shelves used in glass kilns and normally made of pressed high alumina clay.
Battledore :
A square formed tool, used by glass workers having shape of a square wooden paddle with a handle. It is used to smooth the bottoms of vessels and other objects.
Bevel :
Cut and polished edge usually on plate glass at an angle other than 90°, done in stages with roughing, smoothing, cork and felt wheel polishing.
Bird Swing :
A string of glass hanging across the inside layer of a defective glass container. Also referred to as ‘birdcage’.
Blasting :
Shorten term used for sand blasting, a technique of etching and carving glass using an abrasive under pressure.
Blobbing :
The technique of decorating hot glass by dropping onto the surface blobs of molten glass, usually of a different color or colors.
BTU :
An abbreviation for British Thermal Unit – the heat required to increase the temperature of one pound of water by one degree Fahrenheit.
Bubble :
A gas pocket entrenched inside solid glass material.
Buck :
AWood frame surrounding a window unit.
Bullet Resistant :
A glass with multiple laminations of glass and plastic, designed to resist penetration by bullets of small arms and high-power rifles.
Bullions :
One of the few forms of flat glass still produced by the hand process. Bullions or “bulls’ eyes” are used for decorative window glass and are made by reheating and spinning out a bowl-shaped piece of glass.
Burmese :
A type of art glass which is translucent yellow-shading-to-pink.
Bushings :
Made of platinum alloy, electrically-heated boxes with numerous nozzles in their bases used as furnaces for the forming of continuous glass fibre.
Butt Glazing :
The installation of glass products where the vertical glass edges are without structural supporting mullions.
Calcined Alumina :
Calcine means to clean a material by burning or heating. Calcined alumina has been heated in order to remove unwanted material, e.g. water of crystallisation
Came :
A metallic strip of Lead, Brass or Alloy Steel with `H’, ` U’ ‘Y’Shaped cross section used to join pieces of glass. Used mainly for windows and panels.
Carnival Glass :
Inexpensive pressed glass with vivid gold, orange, and purple iridescence, made in the United States between about 1895 and 1924. It is so called because it was frequently offered as fairground prizes.
Cartoon :
The name for the working drawing for a stained glass design which contains all the cutlines. It can also contain paint lines, color, grain directions, piece numbering, an other information. It is essentially the blueprint for the work.
Carving:
It is a technique of removal of glass from the surface to form an object. 3 D Glass Objects can be made with carving with the help of hand tools.
Casement Window :
A window sash hung by hinges and fastened to the window frame.
Casting :
Name given to process and technique to form a glass in a mould.
Chipped Edge :
An imperfection due to breakage of a small fragment from the cut edge of the glass . Generally this is not serious except in heat absorbing glass.
Chunk Glass :
Another name for Dalle-de-Verre and slab glass. Generally they are glasses 8″ x 12″ and 1″ thick.
Cintra Glass :
A type of decorative glass developed by Frederick Carder (1863-1963) at Steuben Glass Works in Corning, New York, before 1917. Most Cintra glass was made by picking up chips of colored glass on the parison and then casing them with a thin layer of (usually) colorless glass.
Clamp :
It is an arrangement used to hold the glass to the work place. Clamping helps in accurate working on glass.
Cold Colour :
Pigments as colour used to decorate glass at ambient (atmospheric) temperature.
Cold Painting :
Applying of cold colours on glass to decorate it or create an image on the surface.
Cold Working :
It is a term to describe the process or working on glass in cold (ambient) condition. No heating is required like Beveling, Edging of glass.
Coloured Glass :
The glass which has colour. Colour can be due to (i) impurities during making (ii) Applying colour externally (iii) Adding various chemicals during manufacturing to get colour (like metal oxides) (iv) Adding colour in the molten state of glass.
Condensation :
The accumulation of water vapor from humidity of the air on any cold surface whose temperature is below the dew point, such as a cold window glass or frame that is exposed to humid indoor air. Low conductivity or warm edge spacers reduce condensation.
Cord :
They are streaks or lines formed due to poor waxing of the batch. Cords are visible due to different reflective indexes thus caused.
Cracking Off :
The process of detachment of glass object from the blow pipe or main mould.
Crizzling :
It is a chemical instability in glass which is irreversible. It is caused by imbalance of ingredients of the batch mainly excess alkali or deficiency of lime. This instable glass is affected by atmospheric moisture, which produces network of cracks on the surface. Techniques are available to retard or stop crizzling.
Crystal :
A Term used to denote colourless high reflective index, bright and brilliant lead glass.
Cruet :
A small, glass vessel, shaped like a sheep, usually with a lip or spout, a handle, and a stopper.
Curtain Wall :
An exterior building wall which carries no roof or floor loads and consists entirely or principally of metal or a combination of metal, glass, and other surfacing materials supported by a metal frame.
Cut Sizes :
Glass cut to specified width & length.
Cutting :
Scoring glass with a diamond, steel wheel, or other hard alloy wheel & breaking it along the score. Other methods of cutting glass include water jet & laser.
Cullet :
Broken glass, excess glass from a previous melt, during manufacture of glass. It is an essential ingredient in the raw batch because it facilitates melting.
Cutting :
A wide term used to remove the glass. To make controlled pieces of glass from sheets by use of automatic or manual methods.
Cutters :
Glass cutters have diamond point to put scaring marks. Also tungsten carbide or hold metal wheels are used to scare the glass for cutting.
Dalle Glass :
Coloured glass, produced in pot furnaces and cast in moulds to form plates in thicknesses of approximately 25 cms. Dalle glass (“dalle” is French for “tile”) is used in church and decorative glazing, as well as for furnishings such as door handles.
Day Tank :
A glass-containing vessel, made from refractory blocks, mainly used for the melting of batch for coloured glass, crystal glass and soft special glasses. Day tanks are refilled with batch daily, with melting, usually done at night and glass production done the following day. Used for producing larger quantities of glass than is possible with pot furnaces.
Deflection :
(centre of glass): The amount of bending movement of the centre of the glass lite perpendicular to the plane of the glass surface under an applied load.
Devitrification :
The crystallisation of a melted substance which generally takes place when the temperature falls below the melting point. Devitrification does not occur with glass either because the rapidly increasing viscosity of molten glass as it cools, impedes crystal growth or because of an insufficient number of nuclei for crystallite formation. Devitrification can be stimulated for the production of opaque glass-ceramics.
Decanter :
A decorative bottle with a stopper used to serve wine and alcohol.
Devitrification :
During the annealing stage of fusing or slumping there is crystallization on the surface of glass due to cooling after the annealing point.
Desicant :
A hygroscopic (That substance which absorbs moisture) substance used to dry/remove moisture in insulating glass i.e. Micro sieve, Silica Gel.
Decibel :
Unit for sound measurement represented as dB.
Decorative Glass :
Term used for glass on which processing has been done to increase the decorative properties of glass. Decorative Glass is used both inside and outside the buildings. Various processes are used to make decorative glass. Stained Glass, Coloring, Etching etc.
Decolourising :
To negate the colouring effect of other material such as iron oxide present in the sand by addition of minerals like (manganese oxide) in the float glass batch. This process is known as decolorizing.
Dichroic :
Glass coated with ultra thin layers of transparent metal oxides to increase the reflection by glass at specific wave length of light. As the angle of incidence of light changes varied bright colours can be seen in glass.
Distortion :
It is an defect on the surface of glass. It shows a wavy optical effect.
Distortion :
Alteration of viewed images caused by variations in the thickness of glass or inhomogeneous portions within the glass.
DIE :
A mould for glass made of metal.
Diatreta :
A term used by Frederick Carder (1863-1963) to describe openwork objects, which he made by lost wax casting.
Dichroic Glass :
Made by vacuum depositing a special coating onto a glass sheet. The process creates a mirror like finish that reflects a specific color but when the glass is held up to the light, a different color is seen (transmitted) through the glass.
Dip Mold :
A cylindrical, one-piece mold that is open at the top so that the gather can be dipped into it and then inflated. See also Optic mold.
Doghouse :
The name used to describe the batch feeding compartment within the furnace. The molten glass is covered with the batch material as it flows through the compartment.
Double Glazing :
Use of two lites of glass, separated by air space, to improve insulation against heat and sound transmission. In insulating glass units, the air between the glass sheets is thoroughly dried & the space is sealed, eliminating possible transmission.
Drawn Glass :
Glass made by ‘Foucault Process’ or ‘Pittsburg Process’. In this process the sheet glass is made by drawing the molten glass as a sheet directly from the furnace. The drawing rate determines the thickness of the glass.
Drilling :
It is the process of making holes in glass by the use of metal bonded glass hollow drills.
Diamond :
Natural and synthetic diamond are impregnated and then sintered to be used for Drilling, Sawing, Edging, Beveling etc. Diamond tools can also be made by electrodepositing diamond. Diamond Points are used on glass cutters to cut glass manually.
Dual Seal :
When both primary seal (Mastic butyl) and secondary seal (Poly Sulphide) are used to make insulated glass, the glass is said to be dual sealed.
Edge Work :
Grinding the edge of flat glass to a desired shape or finish.
Egress Size :
Make size of a window unit that is sufficient to allow a minimum square foot sash opening to meet BOA or local code requirements.
Emissivity :
The measure of the capacity of a surface to emit long-wave infrared radiation.
Etch :
To alter the surface of glass with hydrofluoric acid or other caustic agents. Unintentional permanent etching of glass may
occur from alkali and other run off from surrounding building materials.
Extrusion :
A process for the production of continuous strips or rods of material such as glass and also the butyle used in the sealing of insulating glass units. The material, molten in the case of glass, is forced through a die and cut to the required length.
Ewer :
A container with one handle, used for dispensing liquid.
Facade (or face) :
The whole exterior side of a building that can be seen in one view, usually called the front.
Fan Lamp :
A style of flat lamp whose general shape resembles a ladies fan that is then held upright in base with a socket behind it to provide illumination.
Favrile :
Iridescent glass patented by Louis Comfort Tiffany in the 1880s, produced by the exposure of hot glass to metallic fumes and oxides.
Feldspar :
Also known as “felspar”. Any of a group of aluminium silicates of potassium, sodium, or calcium. Used in the batch as a means of adding alumina to the molten glass.
Felt Wheel :
Used for final polishing of glass. Cerium Oxide powder is used along with these wheels. Generally of two types (1) Made of Compressed Felt (2) Made of compressed felt with resin into strips and then these strips are wound with adhesive to make a spiral wheel. Spiral Felt wheels have a longer life and can work at higher speeds.
Fenestration:
Any type of glass panel, window, door, curtain wall, or skylight unit on the exterior of a building.
Fibre Board :
It is a high density fiber board used for insulation in kiln / furnace. Maximum temperature it can withstand is 2600C°. Usually 1 inch thick fiber board is available in various sheet sizes. Can be cut to suit the requirements.
Fibre Glass :
Consists of fine strands of Glass used to form glass wool for insulation and lining of kiln, furnaces and incubators. Also used for matting and reinforcement. Jet of steam and air are blown as the glass flows out of the tank furnace through very fine small diameter nozzles, resulting in glass to become thin strands.
Fibre Paper :
It is normally 1/8 of an inch thickness used for slumping glass. Maximum Temperature it can withstand is upto 2600C°. It is also used as kiln wash. It is used to make moulds for fusing glass.
Fiber Blanket :
A refractory, flexible sheet used to control the cooling rate of hot glass items.
Finger bowl :
A bowl to hold water for rinsing the fingers at the table.
Finial :
An ornamental glass knob.
Flash Vent :
A quick cooling step (turning off the kiln and opening door for 3 – 8 seconds). This removes trapped gases and releases pressure buildup. This action is taken at the end of final fusing/slumping but before annealing.
Flat Glass :
All types of glass (rolled, float, sheet etc.) independent of the production process are Flat Glasses.
Flush Glazing (Pocket Glazing) :
The setting of a piece of glass or panel into a four-sided sash or frame opening containing a recessed “U” shaped channel without removable stop on three sides of the sash or frame and one channel with a removable stop along the fourth side.
Flux (Stained Glass ) :
A liquid containing metal chlorides to remove the oxide formation on the copper tape and to activate the tape to adhere to the solder. Rub firmly before soldering.
Flux (Fusing) :
It is a substance that lowers the melting temperature of another substance. Potash and Soda are important fluxes.
Frit :
Batch material which is melted with other materials and then ground into powder form before being added to the batch. Lead oxide, which can produce a harmful dust, may be melted with silica, for example, and then ground down as a lead silicate. Glass
Frosting :
Obtaining an OPAQUE MATTE finish on glass surface by exposing to Hydrofluoric Acid . Ammonium Bi fluoride is also used for this purpose.
Furnace :
It is an enclosed structure to heat glass. Heating can be done electrically or burning gas (LPG).
Fusing :
It is the process to insert two or more pieces of glass in a kiln or furnace until they bond to become one non separable piece. Heating of Enameled glass to bond enamel to the surface of glass is also called enamel fusing.
Gas Filled Units :
Insulating glass units with an inert gas (Argon), filled in the space to increase the unit’s sound insulating value.
Gather :
When molten glass is collected at the end of the blowpipe also called gathering Iron, this process is known as to GATHER.
Gilding :
The process of decorating glass by the use of gold leaf, gold paint, or gold dust. The gilding may be applied with size, or amalgamated with mercury. It is then usually fixed to the glass by heat. Gold leaf may be picked up on a gather of hot glass.
Glass :
Glass is a hard amorphous (it is neither solid nor liquid but exists in vitreous stage) material normally fragile and transparent , that we use commonly. It is mainly compound of sand (Silicates SiO2) and alkali (Base)
Glass Bead :
It is round or oval in shape. It is used for decoration, Jewelry and Architectural glass. It can have a center through hole for the cord to make a garland/necklace.
Glass Cutters :
These are hand held instruments used for cutting glass. The cutters can be (1) Diamond tipped (2) Steel wheel type (3) Tungsten carbide wheel type. Kerosene oil is used as lubricant while cutting. Modern day glass cutters have tungsten carbide wheel with automatic flow of cutting oil.
Glass Rods :
These are thin rods of glass used as stirrer (transparent) or colored for fusion made of compatible glass. Many colors and designs are available in these rods.
Glazing :
Fixing of glass on doors or windows. Person who does this job is called glass Glazier.
Glory Hole :
A hole in the side of a glass furnace, used to reheat glass that is being fashioned or decorated. The glory hole is also used to fire-polish cast glass to remove imperfections remaining from the mould.
Glue Chip Glass :
It is a type of artistic glass produced by applying glue (Hot animal glue) and then drying it under specified temperature and humidity conditions. On drying, the glue contracts producing attractive designs like frosting on the glass.
Goethe Glass :
A clear blown glass without seeds or striation, just a slight surface distortion from the blowing process, similar to old window glass.
Gob :
A drop of still molten glass formed by the cutting of the stream of glass as it flows from the forehearth, through a feeder into a spout/orifice of variable diameter; the greater the diameter, the larger the gob. The gobs are fed into the forming machine to be moulded into bottles and other glass objects.
Gold ruby :
Deep red glass coloured by adding gold chloride to it.
Gothic :
A style, generally referring to architecture, found in western Europe from 12th through 16th centuries
Grinder :
It is a tool to grind the edges of glass. These are mainly two types (1) Hand held (2) Table Top Mounted. Stained glass designers use table mounted grinders for grinding glass to the desired shapes.
Grinding :
It is process of removal of glass from the edge (thickness) of glass by using Diamond tools. Grinding tools may have various shapes. The opposite shape of the grinding wheel is obtained on the glass. Grinding is also done to remove sharpness of the edges obtained after cutting of glass.
Grozing :
The process of breaking of the edge of the glass with the help of grozing pliers. This is used to shape the glass as well as to remove unwanted edges.
Grozing Plier :
It is an instrument used for grozing glass. It is of many types.Mainly two types are used by stained glass designers. (1) Narrow grozier (2). Grozier (Broad)/ Breaker. They look like a pliers as the name suggests.
Hand Operated Pressure Gun :
A caulking gun operated by hand to extrude the compound from cartridge. Silicone Sealants are applied with such a gun.
Hand Tools :
Small tools like Piers, Groziers, Breakers, Circle Cutters used for glass working.
Hard Glass :
Glass, that has low co-efficient of expansion, is called Hard Glass. Soda Lime Glass is soft glass whereas Borosilicate Glass is Hard Glass.
Heart :
The separation bar of the H in an H lead. It is the boundary separating pieces of glass in a leaded construction. It is generally 1 1/16″ thick.
Heat Gain :
Solar radiant heat, transmitted by glazing into the building is measured as Heat Gain of the Building. This adds to the built up of heat in the building.
Heat Loss :
The transfer of heat from inside of building to outside through all surfaces of the building is called HEAT LOSS. This loss can be by conduction, convection or radiation. This study is important for centrally heated buildings.
Heat Treated :
Term used for both fully tempered glass & heat-strengthened glass.
Heat-shaded glass :
Glass that shades from one colour to another.
Heat-Strengthened Glass :
Twice as strong as annealed glass; therefore, it is able to resist slightly stronger impacts. Produced in a similar manner to tempered glass (slower cooling than tempered). Heat strengthened glass is not considered safety glass & does not dice completely as does fully tempered glass.
Heat Resistant Glass :
Severe and sudden changes in temperature can only be taken by Heat Resistant Glass. Such a Glass can withstand thermal shocks. It is used mainly to make laboratory equipments. Example: Pyrex Borosil Glass. This type of glass has low co-efficient of expansion.
Hookah (Hukka) :
A bell-shaped or globular glass bottle that is part of the water pipe used mainly in the Islamic countries and India for smoking tobacco.
Hollow Drills :
Are also called Core Drills. These drills are hollow inside. The core of the glass that is drilled comes out as a solid piece and not as powder or flings.
Horizontal Slider :
A window where the movable panel slides horizontally.
Hot End Coating :
Tin Oxide Coating on glass surface to increase mechanical resistance and prepare glass surface for end coating used mainly on bottles, jars and food containers.
Hot Melt :
The adhesive sealant that gets into molten (Flowable) state when heated, and solidifies when cooled, is called Hot Melt Adhesive. Hot melt adhesive is used in Insulated glass as secondary seal. Hot Melt Dispenser is used to apply this sealant.
Hydrofluoric acid :
A highly corrosive acid that attacks silicates such as glass. Pure hydrofluoric acid dissolves glass.
Hydrofluoric Acid (H Fl) :
Highly corrosives acid used for Acid Etching of Glass. It reacts with glass and leaves a smooth polished surface. H Fl. has the property to dissolve the glass.
Inclusions :
A collective term for bubbles, metal and glass particles, and other foreign materials that have been added to the glass for decorative effects.
Inlay :
Any object embedded in the surface of a larger object.
Inleakage :
The unwanted entry of air into a furnace through expansion-created gaps in the furnace superstructure or through other areas such as burner ports, regenerators and exhaust flues. Inleakage can result in decreased efficiency and increased fuel costs.
In Situ :
In position.
Insulated Glass :
Two or more pieces of glass spaced apart and hermetically sealed to form a single-glazed unit with an air space between the glass.
Intaglio (Italian, “Engraving”) :
A method of engraving whereby the ornamentation is cut into the object and lies below the surface plane. The German name for this technique is Tiefschnitt.
Interlayer :
Any material used to bond 2 lites of glass and/or plastic, together to form a laminate.
Jamb :
Thickness of the wall from the inside surface of the house to the outside surface of the house.
Jigs :
Tools or devices used to help aid in the assembly of a project. Generaly by helping hold items in a specific position while being worked with.
Kiln :
An oven made of firebrick used to heat, melt, and shape glass. Electric kilns have wire elements to generate the heat. There are also gas heated and wood burning kilns.
Kiln Forming :
The process of fusing or shaping glass (usually in or over a mold) by heating it in a kiln.
Knop :
A component, usually bulbous, of the stem of a drinking glass.
Kyanite :
A crystalline mineral of aluminium silicate, one of the “sillimanite group of minerals”, occurring in the United States of America and India. Used in the production of non-fusion cast tank blocks.
Laminated Glass :
Constructed by bonding a tough polyvinyl butyral (PVB) plastic interlayer between two pieces of glass under heat and pressure to form a single piece. Can be made of any kind of glass, but is most typically made of annealed, heatstrengthened, or tempered glass.
Lehr :
A long, tunnel-shaped oven for annealing glass, usually by a continuous process
Light Box :
Device used to view glass colors for selection; to trace patterns, or for cutting glass English style.
Lime :
Calcined limestone, which, added to the glass batch in small quantities, gives stability. Before the 17th century, when its beneficial effects became known, lime was introduced fortuitously as an impurity in the raw materials. Insufficient lime can cause crizzling.
Lite :
A term used for a pane of glass used in a window.
Loving cup :
A large drinking glass vessel with two or more handles, passed around at banquets and similar gatherings, used by several persons to drink from it turn by turn.
Low-emittance (Low-E) Coating :
Microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a piece of glass and sealed in an insulating glass unit to reduce the U-Factor. The radiant energy (heat), i.e. long wave infrared, is in effect reradiated back toward its source.
Make Size :
The tip-to-tip width & height measurement of the finished window, in inches.
Masonic glass :
A glass object decorated with emblems or inscriptions used by Freemasons
Metallizing :
Depositing metals apart from silver, onto glass.
Mica :
Mica is fire proof, infusible, incombustible non- flammable material. It can resist temperatures of 600-C to 900-C, depending on the type of mica. It has low heat conductivity, excellent thermal stability and may be exposed to high temperatures without noticeable effect.
Moil :
The unwanted rim of glass, originally in contact with the blowing mechanism or head, left at the neck of a bottle or glass following forming. After being separated from the glass item, the moil can be returned to the glass production cycle as cullet.
Moretti :
Another name used for Italian glass rods melting at a lower temperature and having a coefficient of expansion (COE) of 104.
Mouth Blown :
Glass produced by forcing air, by mouth, through a blowpipe into molten glass
Muff :
A glass cylinder intended to be cut into sheets.
Mullite :
A structurally strong alumino-silicate (3Al O .2SiO ) used in furnace refractory blocks.
Mullion :
A horizontal or vertical member that supports and holds such items as panels, glass, sash, or sections of a curtain wall.
Muntin :
Horizontal or vertical bars that divide the sash frame into smaller lites of glass. Muntins are smaller in dimensions & weight than mullions.
Neodymium :
A rare earth (Nd) used in its oxide form as a colouring agent (producing violet purple tones) and also as a decolourising agent (countering the effects of iron in the batch).
Neo Gothic :
Nineteenth Century revival of Gothic style.
Nipper :
(1) Another name for the type of pliers used in lead came construction. (2) Tool used in mosaic work to break and shape pieces.
Obsidian :
A natural glass of volcanic origin. also known as hyalopsite, Iceland agate, or mountain mahogany.
Oil of Spike :
Solvent for enamel medium.
Opak :
White opal flash on a colored antique.
Opal glass :
Glass that looks like an opal, being translucent or bearing white, grayish or bluish tinge.
Oriel :
A double hung window unit made with one sash larger than the other.
Palm cup :
A shallow drinking glass vessel with a round base that fits in the palm of human hand.
Patina :
A chemical solution applied to the solder or lead to create a different color. Common colors include black, copper, bronze, pewter, green, and antique brass.
Pattern :
(1) A template from which the glass pieces are cut in a stained glass work. (2) The overall design or cartoon for a stained glass work.
Patterned Glass :
One type of rolled glass having a pattern impressed on one or both sides. Used extensively for light control, bath enclosures and decorative glazing. Sometimes called “rolled”, “figured” or “obscure” glass.
Plaque :
An ornamental plate or tablet intended to be hung up as a wall decoration or inserted in a piece of furniture.
Plastic :
Susceptible to being moulded or shaped. When it is in a molten state, glass can be described as plastic.
Pontil, Pontil Mark :
The pontil, or punty, is a solid metal rod that is usually tipped with a wad of hot glass, then applied to the base of a vessel to hold it during manufacture. It often leaves an irregular or ring-shaped scar on the base when removed. This is called the “pontil mark.”
Primer :
A coating specially designed to enhance the adhesion of sealant systems to certain surfaces, to form a barrier to prevent migration of components, or to seal a porous substrate.
Prunt :
A blob of glass, applied to a glass object primarily as decoration, but also to afford a firm grip.
PVB :
The abbreviation for polyvinyl butyral. PVB is used in sheet form as a strong plastic interlayer in the production of laminated glass.
Quarry :
A small square or diamond shaped glass sheet.
Rabbet :
An “L” cut all around the perimeter of the window frames, against which the stained glass panels are installed.
Rasorite :
A partially crude concentrate of sodium borate which, when fully refined, borax is not needed, represents a costefficient source of boric oxide.
Reamy :
Full antique glass with cords of wavy, irregular surface and large bubbles.
Redox :
The abbreviated form of “reduction-oxidation”. The term “redox equilibria” is used to refer to the balance between reduction and oxidation in the glass furnace.
Reed Glass :
Clear commercial glass with half circle ribs (refrigerator shelf glass).
Refractory :
A substance, usually clay with a high percentage of silica, capable of resisting high temperatures.
Reflective Glass :
Glass with a metallic coating to reduce solar heat gain.
Rolled glass :
Glass made by rolling, including patterned and wired glass.
Roman foot :
A flangelike base formed by folding glass.
Saltcake :
Also known as “Glauber’s salt”, the name is given to the chemical substance sodium sulphate, discovered in the 7th century by doctor and chemist Johann Rudolph Glauber. In glassmaking, when mixed with pulverised coal, anhydrous saltcake can be used in the batch instead of soda ash.
Sash :
The portion of the window that holds the glazing, usually the portion of the window that operates.
Score :
o penetrate the surface of a lite of glass by means of a cutting device, in order to produce a lite of glass of a specific size or shape.
Seeds :
Minute bubbles of gas, usually occurring in groups
Seeds :
Minute bubbles in float glass, less than 1/32″ in diameter.
Solar Control Glass :
Tinted and/or coated glass that reduces the amount of solar heat gain transmitted through a glazed product.
Smalt :
Coloured glass, often deep blue glass coloured with cobalt oxide, used as colourants for glass.
Spandrel :
The panel (s) of a wall located between vision areas of windows which conceal structural columns, floors, and shear walls.
Storm door :
A panel or sash door placed on the outside of an existing door to provide additional protection from the elements.
Staple Fibre :
Short lengths of glass fibre, usually U-shaped, which intertwine and are used, in particular, to create insulation materials.
Tinted glass :
Glass with colourants added to the basic glass batch that gives the glass colour, as well as, light and heat-reducing capabilities.
Teardrop :
A drop-shaped air bubble enclosed in a glass.
Tektite :
A naturally formed glass of extraterrestrial or other origin, also referred to as obsidianites.
Transmittance :
The ability of the glass to pass light or heat.
United Inches :
Total of the width & height of the frame opening expressed in full inches.
Uranium Glass :
Glass, coloured with uranium oxide.
Victory Beaker :
A Roman mould-blown drinking glass vessel inscribed in Greek with words meaning Take the victory.
Viscosity :
The quality or state of being viscous; the physical property of a liquid or semi liquid, that enables it to develop and maintain a certain amount of shearing stress, dependent upon the velocity of flow and then to offer continued resistance to flow.
Weathering :
Changes on the surface of glass caused by chemical reaction with the environment. Weathering usually involves the leaching of alkali from the glass by water, leaving behind siliceous weathering products that are often laminar.
Witch Ball :
A glass globe intended to be hung in a prominent in homr or business place, to ward off the evil eye
Zac :
The abbreviation for zircon-alumina electrocast refractories.

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