高硼硅玻璃  Borosilicate glass
Borosilicate glass is a high silicate glass with at least 5% boron oxide bow handle threaded rod with a triangular shaped handle.



Borosilicate glass is a particular type of glass, better known under the brand names Pyrex and Kimax. It was first developed by German glassmaker Otto Schott in the late 19th century and sold under the brand name "Duran" in 1893. After Corning Glass Works developed Pyrex in 1924, it became a synonym for borosilicate glass in the English-speaking world.

Borosilicate glass is the oldest type of glass to have appreciable resistance to thermal impact and higher temperatures, also has excellent resistance to chemical attack. In this glass structure, the first to carry the Pyrex trademark, some of the SiO² is replaced by boric oxide.

Borosilicate glass has a low coefficient of thermal expansion and is, thus, suited for telescope mirrors and other precision parts. Also, because this glass can withstand thermal shock, it is used for oven and laboratory ware, headlamp lenses, and boiler gage glasses. Most borosilicate glasses have better resistance to acids than do soda-lime glasses, but poor resistance to alkalis. Glass fibers used in reinforcing plastic compounds are a modified borosilicate glass.



Chemical Composition

SiO2 = 80.6%

B2O3 = 13.0%

Na2O = 4.0%

Al2O3 = 2.3%



Physical Properties

Coefficient of expansion (20°C–300°C) 3.3 x 10-6 K-1

Density 2.23g/cm3

Refractive index (Sodium D line) 1.474

Dielectric constant (1MHz, 20°C) 4.6

Specific heat (20°C) 750J/kg°C

Thermal conductivity (20°C) 1.14W/m°C

Poisson’s Ratio (25°C – 400°C) 0.2

Young’s Modulus (25°C) 6400 kg/mm2



Optical Information

Refractive index (Sodium D line) = 1.474

Visible light transmission, 2mm thick glass = 92%

Visible light transmission, 5mm thick glass = 91%



Critical Temperatures

150°C - When working above this temperature care should be taken to heat and cool Borosilicate glass in a slow and uniform manner.

500°C - The maximum temperature that Borosilicate glass should be subjected to and then only for short period of no longer than a few minutes.

510°C - Temperature at which thermal stress can be introduced to Borosilicate glassware.

565°C - Annealing temperature. When uniformly heated in controlled conditions, such as a kiln or oven thermal stress’s can be removed.

820°C - Softening point at which Borosilicate may deform.

1252°C - Working point, the temperature that glassblowers need to attain in order to work Borosilicate glass.

Working Temperatures

Borosilicate glass retains its mechanical strength and will deform only at temperatures which approach its strain point. The practical upper limit for operating temperatures is much lower and is controlled by the temperature ditterentials in the glass, which depend on the relative temperatures of the contents of the equipment and the external surroundings.

Provided borosilicate glass is not subjected to rapid change in temperature, creating undue thermal shock, it can be operated safely at temperatures up to 450°F (232°C). The normal limiting factor is actually the gasket material. The degree of thermal shock (usually defined as sudden chilling) which it can withstand depends on many factors, for example: stresses due to operating conditions; stresses imposed in supporting the equipment; the wall thickness of the glass, etc. It is therefore undesirable to give an overall figure but, as a general guide, sudden temperature changes of up to about 216°F (120°C) can be accommodated .

At sub-zero temperatures, the tensile strength of borosilicate glass tends to increase and equipment can be used with safety at cryogenic temperatures.

Further development in glassmaking continues to create new glass-ceramics that outperform borosilicate glass in various ways.

有时候还真希望英文的介绍又来一份中文的全文翻译资料，这样就太好了。

Quartz Glass 石英玻璃
Quartz glass is a clear vitreous solid, formed by melting pure quartz. It can withstand high temperatures and is extremely transparent to infrared, visible, and ultraviolet radiations. It is also known as fused quartz or fused silica. A series of excellent performance features in terms of physical and chemical characteristics make quartz glass a very nice fundamental multi-purpose material.

Heat resistance
The temperature of the softening point for quartz glass is about 1730. Generally, quartz glass can be placed in conditions of 1100 for a long duration, but in the short-term, the maximum temperature is 1450.
Anticorrosion
Quartz glass has 30 times the resistance property of ceramics to corrosion and 150 times that of stainless steel, and does not react with other acids chemically except for hydrofluoric acid. Especially in terms of chemical stability under high temperatures, quartz glass is unmatchable compared to other engineering materials.
Good thermostability
The coefficient of thermal expansion of quartz glass is small, so it can endure sharp temperature variations. It will not crack even if placed into water with a normal temperature after heating the glass to 1100.
Excellent light-transmission performance
Quartz glass give off a beautiful light transmission performance with a full spectral band from ultraviolet to infrared, with more than 93% for visible light, and going beyond 80% in ultraviolet light.
Good electric insulation capability
The electric resistance value of quartz glass is 10,000 times that of ordinary glass. It is a very good electric insulation material with outstanding performance even in high temperature conditions.
Quartz glass can be widely applied in the fields of electric light sources, semiconductors, light communications, the military, construction, environmental protection, chemistry?and so on.

Float Glass  浮法玻璃
Float glass is a sheet of glass made by floating the molten glass on a bed of molten tin. This method gives the glass uniform thickness and very flat surfaces. Modern window glass is float glass.


History

In earlier centuries, window glass or flat glass was made by blowing either large cylinders or large disks. The cylinders were cut apart and flattened and then window panes were cut from the large surface. Most glass for windows up to the early 19th century was made from rondels, while most window glass during the 19th century was made using the cylinder method (these 'cylinders' were 6 to 8 feet (2 to 2.5 m) long and 10 to 14 inches (250 to 350 mm) in diameter).

The flat glass process was patented in 1848 by Henry Bessemer, an English engineer was the first attempt to make a continuous ribbon of flat glass by forming the ribbon between rollers. The forming of flat glass on a tin bath was described in patents in the United States in 1902 by W. E. Heal and again in 1925 by Hitchcock (a revised version of Heal's patent). Between 1953 and 1957, (Sir) Alastair Pilkington and Kenneth Bickerstaff of the UK's Pilkington Brothers developed the first successful commercial implementation of the forming of a flat glass continuous ribbon glass using a molten tin bath on which the molten glass flows laterally unhindered to the limit of its free flow under the influence of gravity and surface tension. Neither Heal nor Hitchcock had described this free flow process. Full scale profitable sales of float glass were first achieved in 1960.

Before the development of float glass, larger sheets of plate glass were made by casting a large puddle of glass on an iron surface, and then grinding and polishing both sides to smooth clarity, a very expensive process. From the early 1920s, a continuous ribbon of plate glass was passed through a lengthy and expensive series of inline grinders and polishers, helping to reduce glass losses and production costs.

Glass of lower quality, sheet glass, was made by drawing upwards from a pool of molten glass a thin sheet, held at the edges by rollers. As it cooled the rising sheet stiffened and could then be cut. The two surfaces were less parallel and of lower quality than those of float glass. This process continued for many years after the development of float glass.

Manufacture

Float glass is made by melting raw materials consisting of sand, limestone, soda ash, dolomite, iron oxide and salt cake. The raw materials are mixed together and fed into a large furnace that is natural gas or fuel oil fired. The raw materials, referred to as batch, blend together to form a large pool of molten glass. The molten glass is fed into the float bath (tin bath) through a delivery canal. The amount of glass allowed to pour onto the molten tin is controlled by a refractory gate called a tweel. The tin bath is provided with a protective atmosphere consisting of a mixture of nitrogen and hydrogen to prevent oxidation of the tin. The glass flows out onto the tin surface forming a floating ribbon with perfectly smooth glossy surface on both sides with an even thickness of approximately 4 mm. Thinner glass is made by stretching the glass ribbon to achieve the proper thickness. Thicker glass is made by not allowing the glass pool to flatten to 4 mm. Machines called attenuators are used in the tin bath to control both the thickness and the width of the glass ribbon.

As the glass flows down the tin bath, the temperature is gradually reduced until the sheet can be lifted from the tin onto rollers. It then passes through the lehr where it is further cooled gradually so that it anneals without strain and does not crack from the change in temperature. The glass travels down the rollers in the lehr for about 100 metres and comes out at the "cold end" where it is cut by machines.

Some tin is absorbed into the glass, and with a proper ultraviolet light a sheen can be seen which differentiates the tin from the non-tin side.

good.very good!

Spandrel glass 实墙外装饰玻璃， 有人将它翻成磨砂玻璃，或拱肩玻璃

Glass has become one of the most important materials used in construction, especially for high-rise commercial buildings. As it typically covers a large part of exterior surfaces the correct choice of glass is most important to obtain the right final result.


 附件: 您所在的用户组无法下载或查看附件Today, different curtain wall systems allow the entire building exterior to be covered with glass. To cover non-visible areas a so-called spandrel glass is used. Spandrel's primary function is to cover materials or construction elements from being viewed from the exterior of the building. Examples of such areas include areas between floors, hung ceiling areas, knee-wall areas below vision lights, and sometimes even columns or partitions.
Aesthetically, it can be applied in two ways. One is to contrast the appearance of the vision panels through the use of color, while another is to match it with the vision area, so that from the outside the structure maintains a uniform glass skin making it virtually impossible to distinguish where the start and finish of the window and wall. When trying to create an exterior uniform appearance colors and the optical properties of the vision area glass must be considered. As for the different lighting conditions behind the spandrel and other factors, it is practically impossible to obtain a perfect match, however paying attention to details usually produces greater uniformity.

Spandrel glass is usually produced by a fired-on frit process in which a ceramic frit is applied to annealed glass and then tempered to fuse the frit with the glass. The result is a non-vision glass panel that does not fade. As this glass is heat-treated during the manufacturing process, it supply adequate resistances to thermal stresses. This glass can also be insulated to increase its thermal performance.

Self-cleaning glass 自洁玻璃

 附件: 您所在的用户组无法下载或查看附件
Self-cleaning glass was one of the major attractions at the Pilkington and Saint Gobain exhibits stands in Dusseldorf. These exhibitors dedicated a significant area of their booth to promote this type of glass, certainly emphasizing the importance of this product.

Self-cleaning glass is an ordinary float glass with a special photocatalytic coating. It is made by chemically bonding and integrating a microscopically-thin surface layer to the exterior surface of clear glass. The integrated coating reacts to the sun?s ultraviolet rays to gradually and continuously break down organic dirt through what is called a photocatalytic effect. In other words photocatalytic means that the active integrated coating on the outside of the glass absorbs the sun?s ultraviolet rays. This causes a reaction on the surface which breaks down dirt and loosens it from the glass. This type of glass also has hydrophilic properties, meaning that rain flows down the pane as a sheet, washing away the dirt instead of, as with normal glasses, leaving the dirt behind. As a result of these two effects, the special self-cleaning coating keeps the glass cleaner for a longer period than with normal glass in applications where it is exposed to the rain. Find more information on the selected links.

Laminated Glass 夹层玻璃
Laminated (or compound) glass consists of two or more sheets of glass with one or more viscous plastic layers "sandwiched" between the glass panes. The solid joining of the glasses takes place in a pressurised vessel called an autoclave. In the autoclave, under simultaneous heating of the already processed layers of glass and special plastic, lamination occurs. When laminated safety glass breaks, the pieces remain attached to the internal plastic layer and the glass remains transparent.


Laminated glass is a type of safety glass that holds together when shattered. In the event of breaking, it is held in place by an interlayer, typically of PVB, between its two or more layers of glass. The interlayer keeps the layers of glass bonded even when broken, and its high strength prevents the glass from breaking up into large sharp pieces. This produces a characteristic "spider web" cracking pattern when the impact is not enough to completely pierce the glass.

Laminated glass is normally used when there is a possibility of human impact or where the glass could fall if shattered. Shopfront glazing and windshields are typically laminated glasses. The PVB interlayer also gives the glass a much higher sound insulation rating, due to the damping effect, and also blocks 99% of transmitted UV light.

Laminated glass was invented in 1903 by the French chemist Edouard Benedictus, inspired by a laboratory accident. A glass flask had become coated with the plastic cellulose nitrate and when dropped shattered but did not break into pieces. Benedictus fabricated a glass-plastic composite to reduce injuries in car accidents. However, it was not immediately adopted by automobile manufacturers, and the first widespread use of laminated glass was in the eyepieces of gas masks during World War I.

Today, laminated glass is produced by bonding two or more layers of ordinary annealed glass together with a plastic interlayer, usually polyvinyl butyral (PVB). The PVB is sandwiched by the glass which is passed through rollers to expel any air pockets and form the initial bond then heated to around 70 °C in a pressurized oil bath. The tint at the top of some car windshields is in the PVB.

A typical laminated makeup would be 3 mm glass / 0.38 mm interlayer / 3 mm glass. This gives a final product that would be referred to as 6.38 laminated glass.

Multiple laminates and thicker glass increases the strength. Bulletproof glass is often made of several float glass, toughened glass and Perspex panels, and can be as thick as 100 mm. A similar glass is often used in airliners on the front windows, often three sheets of 6 mm toughened glass with thick PVB between them.

Laminated glass is also sometimes used in glass sculptures.

Thanks for sharing~ It's very useful for me!

Glassblowing  玻璃吹制

 附件: 您所在的用户组无法下载或查看附件
Glassblowing is the process of forming glass into useful shapes while the glass is in a molten, semi-liquid state. A person who blows glass is called a glassblower, glassmith, or gaffer.


History

While the first evidence of man-made glass occurs in Mesopotamia in the Late-Third/Early-Second Millennium B.C., the actual "blowing" of glass using a tube did not occur until sometime in the First century BC in Roman Syria. Glassblowing is a form of art that requires extreme training and an intense level of aptitude. This advancement transformed the material's usefulness from a time-consuming process in which the medium was hot-formed around rough cores of mud and dung into a mass-producible material which could be quickly inflated into large, transparent, and leak-proof vessels. Glassblowing techniques spread throughout the Roman world. Venice, particularly the island of Murano, became a centre for high quality glass manufacture in the late medieval period.

The relatively recent "studio glass movement" began in 1962 when Harvey Littleton, a ceramics professor, and Dominick Labino, a chemist and engineer, held two workshops at the Toledo Museum of Art, during which they began experimenting with melting glass in a small furnace and creating blown glass art. Thus Littleton and Labino are credited with being the first to make molten glass available to artists working in private studios. This approach to glassblowing blossomed into a worldwide movement, producing such flamboyant and prolific artists as Dale Chihuly, Dante Marioni, Fritz Driesbach and Marvin Lipofsky. Lino Tagliapietra was the first Murano-trained artist to leave and spread his knowledge in the United States. In 1971, Dale Chihuly began the Pilchuck Glass School near Stanwood, Washington. The Pilchuck School of Glass became the source of a great deal of the current American Studio Glass movement, and continues as such today.

In addition to glassblowing as an art, many individuals pursue glassblowing as a hobby. In fact, it is one of the fastest growing hobbies in North America.


Process

Traditionally, the glass was melted in furnaces from the raw ingredients of sand, limestone, soda ash, potash and other compounds. The transformation of raw materials into glass takes place well above 2000°F (1100°C); the glass turns into a burnt orange color, the glass is then left to "fine out" (allowing the bubbles to rise out of the mass), and then the working temperature is reduced in the furnace to around 2000°F (1100°C). "Soda-lime" glass remains somewhat plastic and workable, however, as low as 1000°F (550°C).

Glassblowing involves three furnaces. The first, which contains a crucible of molten glass, is simply referred to as "the furnace." The second is called the "Glory Hole", and is used to reheat a piece in between steps of working with it. The final furnace is called the "lehr" or "annealer", and is used to slowly cool the glass, over a period of a few hours to a few days, depending on the size of the pieces. This keeps the glass from cracking due to thermal stress. Historically, all three furnaces were contained in one, with a set of progressively cooler chambers for each of the three purposes. Many glassblowing studios in Mexico and South America still employ this method.

The major tools involved are the blowpipe, the punty (or pontil), bench, marver, blocks, jacks, paddles, tweezers, and a variety of shears. The tip of the blowpipe is first preheated; then dipped in the molten glass in the furnace. The molten glass is 'gathered' on to the blowpipe in much the same way that honey is picked up on a dipper.

Then, this glass is rolled on the marver, which was traditionally a flat slab of marble, but today is more commonly a fairly thick flat sheet of steel. This forms a cool skin on the exterior of the molten glass and shapes it. Then air is blown into the pipe, creating a bubble. Then, one can gather over that bubble to create a larger piece. Blocks are ladle-like tools made from water-soaked fruit wood and are used similarly to the marver to shape and cool a piece in the early steps of creation. The bench is a glassblower's workstation, and has a place for the glassblower to sit, a place for the handheld tools, and two rails that the pipe or punty rides on while the blower works with the piece. Jacks are a tool shaped somewhat like large tweezers with two blades. Jacks are used for forming shape later in the creation of a piece. Paddles are flat pieces of wood or graphite used for creating flat spots like a bottom. Tweezers are used to pick out details or to pull on the glass. There are two important types of shears, straight shears and diamond shears. Straight shears are essentially bulky scissors, used for making linear cuts. Diamond shears have blades that form a diamond shape when partially open. These are used for cutting off masses of glass. Once a piece has been blown to its approximate final size, the bottom is finalized. Then, the piece is transferred to a punty, and the top is finalized. The entire process of a basic wine glass can be seen here and a simple striped bowl here. There are many ways to apply patterns and color to blown glass, including rolling molten glass in powdered color or larger pieces of colored glass called frit. Complex patterns with great detail can be created through the use of cane (rods of colored glass) and murrine (rods cut in cross-sections to reveal patterns). These pieces of color can be arranged in a pattern and 'picked up' by rolling a bubble of molten glass over them. An overview of how a piece is made from mixed cane and murrine is shown here. One of the most exacting and complicated caneworking techniques is 'reticello', which involves creating two bubbles from cane, each twisted in a different direction and then combining them and blowing out the final form. View a step-by-step reticello demonstration.


A lampworker, usually operating on a much smaller scale, historically used alcohol lamps and breath or bellows-driven air to create a hot flame at a workbench to manipulate preformed glass rods and tubes. These stock materials took form as laboratory glass, beads, and durable scientific "specimens" — miniature glass sculpture. The craft, which was raised to an art form in the late 1960's by Hans Godo Frabel (later followed by lampwork artists such as Milon Townsend and Robert Mickelson), is still practised today. The modern lampworker uses a flame of oxygen and propane or natural gas. The modern torch permits working both the soft glass from the furnace worker and the borosilicate glass (low-expansion) of the scientific glassblower who may have multiple headed torches and special lathes to help form the glass or fused quartz used for special projects. The molten glass is attached to a stainless steel or iron rod called a punty (or a punty rod, a pontil, or a mandrel) for shaping and transferring a hollow piece from the blowpipe for an opening to create from.

Glass Bead making 玻璃珠制作
Beads are among the oldest human art and technology, dating back 30,000 years (Dubin, 1987). Glass beads have been dated back to at least Roman times. Perhaps the earliest glass-like beads were Egyptian faience beads, a form of clay  bead with a self-forming vitreous coating.

Common Types of Glass Beads
Glass beads are usually categorized by the method used to manipulate the glass. Most beads fall into three main categories: wound beads, drawn beads, and molded beads. There are composites, such as millefiori beads, where cross-sections of a drawn glass cane are applied to a wound glass core. A very minor industry in blown glass beads also existed in 19th century Venice and France.

Wound Glass Beads
Probably the earliest beads of true glass were made by the winding method. Glass at a temperature high enough to make it workable , or "ductile", is laid down or wound around a steel wire or mandrel coated in a clay slip called "bead release."

The wound bead while still hot may be further shaped by manipulating with graphite, wood, stainless steel or marble tools and paddles, this process is called marvering, originating from the French word "Marver" which translates to "Marble". It can also be pressed into a mold in its molten state. While still hot, or after re-heating, the surface of the bead may be decorated with fine rods called stringers of colored glass. These are called lampwork beads.

Drawn Glass Beads
The drawing of glass is also very ancient. Evidence of large-scale drawn-glass beadmaking has been found by archeologists in India, at sites like Arekamedu

dating to the 2nd century CE. The small drawn beads made by that industry have been called Indo-Pacific beads, because they may have been the single most widely traded item in history--found from the islands of the Pacific to Great Zimbabwe in southern Africa.

There are several methods for making drawn beads, but they all involve pulling a strand out of a gather of glass in such a way as to incorporate a bubble in the center of the strand to serve as the hole in the bead. In Arekamedu this was accomplished by inserting a hollow metal tube into the ball of hot glass and pulling the glass strand out around it, to form a continuous glass tube. In the Venetian bead industry, molten glass was gathered on the end of a tool called a puntile ("puntying up"), a bubble was incorporated into the center of a gather of molten glass, and a second puntile was attached before stretching the gather with its internal bubble into a long cane. The pulling was a skilled process, and canes were reportedly drawn to lengths up to 200 feet long. The drawn tube was then chopped, producing individual drawn beads from its slices. The resulting beads were cooked or rolled in hot sand to round the edges without melting the holes closed; were sieved into sizes; and, usually, strung onto hanks for sale.

A modern example of mechanically-drawn glass beads is the micro-bead or "seed bead", so called for its tiny, regular size. Seed beads are the most common type of modern glass bead. The seed bead is a small bead typically less than 6 mm, traditionally monochrome, and manufactured in very large quantities. Modern seed beads are extruded by machine and some, (Miyuki delicas) look like little tubes.

Molded Beads
Increasing in labor costs are pressed or molded beads. These were (and are) made in the Czech republic, in what was once called Bohemia. Thick rods (20cm?) are heated to molten and fed into a rube goldbergian contraption that stamps the glass, including a needle that pierces a hole. The beads again are rolled in hot sand to remove flashing and soften seam lines. By making canes (the glass rods fed into the machine) striped or otherwise patterned, the resulting beads can be more elaborately colored than seed beads. One `feed' of a hot rod might result in 10--20 beads, and a single operator can make thousands in a day.

The Bohemian glass industry was known for its ability to copy more expensive beads, and produced molded glass "lion's teeth", "coral", and "shells", which were popular in the 19th and early 20th century Africa trade.

Lampwork Beads

A variant of the wound glass beadmaking technique, and a labor intensive one, is what is traditionally called lampworking. In the Venetian industry, where very large quantities of beads were produced in the 19th century for the African trade, the core of a decorated bead was produced from molten glass at furnace

temperatures, a large-scale industrial process dominated by men. The delicate multicolored decoration was then added by people, mostly women, working at home using used an oil lamp or spirit lamp to re-heat the cores and the fine wisps of colored glass used to decorate them. These workers were paid on a piecework basis for the resulting lampwork beads. Modern lampwork beads are made by using a gas torch to heat a rod of glass and spinning the resulting thread around a metal rod covered in bead release. When the base bead has been formed, other colors of glass can be added to the surface to create many designs. After this initial stage of the beadmaking process, the bead can be further fired in a kiln to make it more durable.

Modern beadmakers use single or duel fuel torches, so `flameworked' is replacing the older term. Unlike a metalworking torch, or burner as some people in the trade prefer to call them, a flameworking torch is usually "surface mix"; that is, the oxygen and fuel (typically propane, though natural gas is also common) is mixed after it comes out of the torch, resulting in a quieter tool and less dirty flame. Also unlike metalworking, the torch is fixed, and the bead and glass move in the flame. American torches are usually mounted at about a 45 degree angle, a result of scientific glassblowing heritage; Japanese torches are recessed, and have flames coming straight up, like a large bunsen burner; Czech production torches tend to be positioned nearly horizontally.

Dichroic Glass beads
Increasingly, dichroic glass is being used to produce high-end art beads. Dichroic glass has a thin film of metal fused to the surface of the glass, resulting in a surface that has a metallic sheen that changes between two colors when viewed at different angles. Beads can be pressed, or made with traditional lampworking techniques.

Furnace Glass
Italian glass blowing techniques such as latticinio and zanfirico are adapted here to make beads. Furnace glass uses large decorated canes built up out of smaller canes, encased in clear glass and then extruded to form the beads with liner and twisting stripe patterns. No air is blown into the glass. These beads require a large scale glass furnace and annealing kiln for manufacture.

Lead crystal

Lead crystal beads are machine cut and polished. Their high lead content makes them sparkle more than other glass, but also makes them inherently fragile.

Types of glass used in Lampwork beads
Rod versus Sheet

Most lampworkers use rods of glass 7--8 mm in diameter, though premade stringers come in 1, 2 and 3 mm sizes (depending on the brand), and some brands come in very thick diameters (15mm or more.) Sheet glass can be cut with tools into strips, though they're easier to manipulate if attached to a rod first. (Glass also comes in particles of various sizes(frit or powder), but these are typically surface decorations in lampworked beads.) Many manufacturers who once only sold their glass in sheet or very thick rod now provide rods for lampworking use.

Window glass can actually be used, but usually isn't, because it's not formulated for flameworking (it's shocky, that is, cracks and shatters in the flame) and there is little in the way of color available.

Soda LIME

The most popular lampworking glass comes from Italy and is currently made by the Effetre company. Before it was sold, it was called Moretti, and some people still call it that. Confusing matters is that a cousin started a rival company; their product is called Vetrofond, and is very similar. Effetre is a soda-lime glass, and, again is the type most commonly used by lampworkers. Perhaps the second most popular soda-lime glass (in the USA) is made by Bullseye, which markets their product as being particularly compatible (find/link/write article about glass coe/compatibility). Spectrum, Uroboros make 96coe glasses. Japanese Satake, German Lauscha, Czech (Ornela) and even Indian (PIG) soda lime glasses are also known. New firms seem to be springing up like weeds to serve the glass beadmaking market, which in the USA has grown from "about 30" to 70,000 people (Kate Drew Wilkerson, interview, Dale Smeltzer's internet-only glass talk radio)

Lead

In addition to soda lime glass, lampworkers can use lead glass. Lead glasses are distinguished by their lower viscosity, heavier weight, and somewhat greater

tolerance for coe mismatches. Satake, Czech and German glasses (the latter being marketed primarily to glassblowers) all come in lead versions. New to the market is also Gaffer Glass, its 96 coe and is made in New Zealand.

Borosilicate

Finally, beadmakers can and do use borosilicate glass, a very hard glass requiring greater heat. This is laboratory glass, such as Pyrex. Sue Ellen Fowler is credited for developing many of the original recipes for colored borosilicate glasses, which became the basis for the Northstar company's first products. Donald Schneider (personal conversation, late 1990s) recalls how years ago he had to make all of his own borosilicate colors (he still makes a tin white.) Northstar, and new Glass Alchemy (started by a former chemist at Northstar) now offer many colors, introducing several new ones every year. At one time, soft (soda lime and lead) and hard (boro) glasses had distinctly different looking palettes, but demand on the part of soft-glass artists for the silver strike colors on the one hand, and the development of the bright, cadmium based `crayon colors' in the boro line on the other, has softened the distinctions between them considerably.

Basic Technique for Lampworking

Preparing the mandrel

In any case, the beadmaker starts by dipping a mandrel, or wire (stainless steel welding wire, cut into 9 or 12inch lengths is typical, at least in the USA) into a clay based substance similar to kiln wash and letting it dry. Some brands allow for drying

in the flame.

Heating rod and mandrel

The flameworker then selects rods of glass which they heat in the flame of her torch. The mandrel must also be heated, or the glass will not stick. When both glass nd mandrel are sufficiently warm, the beadmaker starts rotating the mandrel (usually with the non-dominant hand) while allowing the glass to wind upon it---sort of like pulling out a strand of cotton candy, or wool batt while spinning.

Beginner Bead

The usual beginner bead is a simple donut shape. The beadmaker can use a paddle, a small slab of graphite or brass to shape the glass in different ways---long thin barrels, cones, tabs, bicones and so on. Czech beadmakers, who can produce up to 1200 (identical) lampwound beads in 2--3 days, are particularly known for their use of jigs to help rapidly shape the bead into the desired silhouette.

Shaping the Bead

Getting a good shape is quite often the longest part of the process, though onlookers tend to be most impressed with surface decoration. Some beadmakers

rely solely upon heat and gravity to shape their beads; most at least use a graphite paddle to coax the bead into the shape they want. Other common tools for shaping beads are mashers, tweezers, picks, and even the rod of glass itself. The use of presses to create shapes and indent patterns into the glass has been a recent development of modern beadmaking.


Decorating the Bead

There are many ways to decorate a bead. One is to draw with a stringer, or fiber (a small thread, usually 3 mm or less in diameter) of glass on the surface, making dots, lines, or combinations. Dots are particularly versatile and can be piled on top of each other in many intriguing ways. Additionally, a sharp pointed object---for example, a tungsten rake (or pick) or stringer of glass can be dragged through the surface design to make feathers, hearts or other designs. Another very old, traditional design involves sagging one part of a striped bead by heating it more, or rubbing it with the paddle to shift the design into waves.

Glass can also be broken into very small chunks (frit) or even finely ground powders (e.g. Thomspson enamels) in which the bead can be rolled; it can also be

decorated with metals---silver, gold, copper, palladium, and platinum. These are typically applied as very fine leaf, slightly thicker foil, as fine wire, as fine mesh, or even as a metallic deposit (fuming.)

Annealing

Good quality glass beads, like any warm or hot-glass item such as Large or complex beads go into an annealing kiln immediately; smaller ones may be allowed to cool slowly, as with a fiber blanket or by being plunged into vermiculite, and then "batch annealed" at a later time

Other methods for making glass beads

Lead glass (for neon signs) and, especially borosilicate is available in tubing, making true blown beads possible. (Soda lime glass can be blown at the end of a metal tube, or, more commonly wound on the mandrel to make a hollow bead, but the former is unusual and the latter not a true mouth-blown technique.) In addition, beads can be fused from sheet glass or using ground glass.

Modern Ghana has a lively industry in beads molded from powdered glass. Also in Africa, the famed Kiffa beads are made in Mauritania, historically by women, using powdered glass that the beadmaker usually grinds herself from commercially available glass seed beads and recycled glass.

Molded ground glass, if painted into the mold, is called pate de verre, and the technique can be used to make beads, though pendants and cabochons are more typical. Lampwork (and other) beads can be painted with glass paints.

Additional Techniques for Lampworked beads

Beads can be sandblasted; they can be faceted, using lapidary techniques. "Furnace glass" beads, more elaborate versions of the old seed bead technique

described above, are also being made. Chevron beads are multi-layer beads once exclusively made using hot-shop techniques to produce the original tubing; but now some lampworkers make similar designs on their torches (using borosilicate,--Kevin O'Grady, demonstration, 2004 Gathering) before lapping the ends to reveal the various layered colors. It should be noted that as torches get bigger and more powerful, the cross-over between lampworking and furnace glass continues to increase.

Brief history of modern beadmaking

Lampworked beads (with the exception of Asian and African beadmaking) have pretty much strictly been the provenance of Italian, and, later, Bohemian

lampworkers for the last four hundred years or so who kept the techniques secret. Thirty or so years ago, some American artists started experimenting with the form. Their early efforts, by today's standards, were crude-not surprising when there was almost no documentation, and none of the modern tools. However, they shared their information, and some of them started small businesses developing tools, torches and other equipment. The "stump shaper" a popular shaped paddle, is named after Loren Stump, for example.

This group eventually formed basis for the Society of Glass Beadmakers, which recently changed its name to the International Society of Glass Beadmakers.

Techniques diffused through the population, via early books such as Cindy Jenkins' You can make Glass Beads; the ISGB's annual conference and their online forum; and just generally the philosophy of sharing ideas, tips and techniques. This philosophy continues to permeate the glass beadmaking world today, resulting in a huge diversity of approaches, styles and beads.

Kate, 你好强啊，are you working for a glass company or a translation company?

我想问下高硼硅玻璃　中国是不是具有领先优势呢？

I work for China Glass Network, but before i am dealing business with exporting and importing

Kate it's very nice to know you ,My name is wujun , Anyway i want improve my oral english,....urgently..... Cay you do me a favor?