FIBER BLANKET — Usually 1/16” to 1” used as a baffle to prevent glass sticking to kiln furniture, casting rings, and dams. Also used to insulate small glass objects and beads from cooling too quickly.
FIBER BOARD — Usually 1/2” or thicker, this material can be cut to make shelves, kiln posts, or molds.
FIBER PAPER — Usually 1/32” used to protect the kiln shelf. Fiber Rope; Available in varying thickness, used to create textures and channel barriers in glass.
FINISHING — The procedure of concluding the shaping process
FINE SILVER WIRE — Wire that assays at .999 pure silver. This wire can withstand the temperatures inside the kiln. Once cleaned it will shine up to bright silver after it is fused.
FIRING — The process of heating clay or glass within a pottery kiln.
FIRE POLISHING — Reintroducing the glass to heat in a kiln, flame, or furnace in order to melt away any irregularities, smooth and round edges, and develop a shiny appearance, without distorting the pattern on a mold, blown, or pressed glass piece. Usually performed after glass has been ground or sandblasted.
FIRING LOG — Log of various firing schedules. Assists in understanding what has happened in past procedures.
FIRING SCHEDULE — Written details of the times and rates of heating and cooling during a particular cycle. The entire collection of heating rates, set point temperatures and soak times associated with a particular firing.
FIT — Compatible glass is said to "fit" each other.
FLAMEWORK — The technique of forming objects from rods and tubes of glass that, when heated in a flame, become soft and can be manipulated into a desired shape. Historically, the source of the flame was an oil or paraffin lamp used with a foot-powered bellows, but today bench torches are used, which provide an intense, oxygenated natural gas or propane flame. This technique is also referred to as Lampworking.
FLASHED GLASS — A sheet of glass composed of a base layer of one color with a thin contrasting layer of another color flashed or fused to the surface. Flashed glass is often used for etched or sandblasted glass art. When sections of the thin color layer are removed, the base color shows through.
FLASHED ON COLOR — highlighting crystal glass with colored stain, commonly amber or red, by reheating the piece to fuse or flash the color to the surface of the piece, tends to rub off more easily with use than color which is fired on.
FLASHING — Quickly placing the working glass into the glory hole to reheat the entire piece. This is meant to ensure that the glass will remain pliable and be kept safe from cracking.
FLASH VENTING — Opening the kiln door or lid during the firing process to stop the process.
FLOAT GLASS — Commonly known as window glass. It has been created by flowing molten glass on a bed of hot tin. This causes it to have a shiny polished surface on both sides of the glass. The process leaves an invisible tin film on the glass that is only relevant if you are fusing with float glass. A tin scope is necessary in order to determine the tin side of the float glass.
FLUID ZONE — Also referred to as molten zone. Glass becomes fluid like and can flow. This occurs above 1350 degrees Fahrenheit. Fusing of the glass occurs around 1500 - 1600 degrees Fahrenheit.
FLUX — A substance, which causes or promotes melting. A Chemical agent (liquid or paste) used to facilitate the flow of solder and prevent formation of oxides during soldering (Stained glass work term).
FOOT — The base of an object; the part on which it rests.
FRACTURES AND STREAMERS — In the single roll process of glass making thin glass chips or shards (fractures) and/or glass string (streamers) are arranged on the casting table before the glass is poured, and thus pressed into the glass sheet as it is formed.
FREE BLOWN (off-hand blown) GLASS — Glassware shaped solely by inflation with a blowpipe and manipulation with tools.
FREEZE AND FUSE — The process of mixing powder glass and water in a flexible mold, freeze and then fired in a kiln. A type of "pate-de-verre"
FRIT — A broad term that refers to crushed or ground glass. It usually comes in different sizes, coarse, medium, fine, or powder. Frit is used as a coloring agent or for decorative effect in hot glass crafts like blowing and fusing. May be ground into a powder prior to being added to a ceramic glaze recipe.
FRIT CASTING — Filling a mold with frit (ground glass) and heating it until the frit fuses into a solid mass.
FRITTING — The process of creating frit.
FURNACE — An enclosed structure for the production and retention of heat, used for melting glass batch and maintaining glass in a molten state.
FURNITURE — A collective term for the various posts and shelving used to support and separate the ceramics or glass within the kiln chamber
FULL FUSE — Heating two or more pieces of glass until they completely melt and flow together.
FUSE, FUSING — To melt. The process of heating multiple pieces of glass until they bond. Over several hours, the temperature in the kiln is slowly brought up to fusing temperature, 1510° F (820° C), and then slowly cooled down again. Refers to specially designed glass that has been fused or melted together in a kiln. The process of placing different pieces of glass in contact with each other in an arranged design, then firing them in a kiln at a temperature high enough to bond them into one piece of glass.
FUSING GLOVES — Gloves used to pick up hot glass and for opening up your kiln while it is in the fusing process.
FUSING GLUE — Liquid adhesives used to hold glass pieces in place while transferring them from your work place to the kiln shelf.
FORE HEARTH – A shallow chamber through which molten glass passes on its way from a continuous melting furnace to the forming process. The purpose of this chamber is to allow the temperature of the glass to drop from melting temperatures (about 2,700°F) to forming temperatures (about 2,200°F for 1/8" thick sheet glass).