Glass beadmaking
Encyclopedia
The technology for glass beadmaking is among the oldest human arts, dating back 3,000 years (Dubin, 1987). Glass
bead
s 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.
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 (61 m) 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.
The most common type of modern glass bead is the seed bead, a small type of bead typically less than 6 mm, traditionally monochrome, and manufactured in very large quantities.They are a modern example of mechanically-drawn glass beads. The micro-bead or "seed bead", are so called due to their tiny, regular size. Modern seed beads are extruded by machine and some, such as Miyuki delicas, look like small tubes.
Pressed or molded beads are associated with lower labour costs. These are made in the Czech republic
. Thick rods are heated to molten and fed into a complex apparatus 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.
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 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 dual 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.
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. If the glass is kept in the flame too long, the metallic coating will turn silver and burn off.
and anneal
ing kiln
for manufacture.
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 an industry in beads molded from powdered glass. Also in Africa, 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 pendant
s and cabochon
s are more typical. Lampwork (and other) beads can be painted with glass paints.
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
bead
Bead
A bead is a small, decorative object that is usually pierced for threading or stringing. Beads range in size from under to over in diameter. A pair of beads made from Nassarius sea snail shells, approximately 100,000 years old, are thought to be the earliest known examples of jewellery. Beadwork...
s have been dated back to at least Roman
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
times. Perhaps the earliest glass-like beads were Egyptian faience
Egyptian faience
Egyptian faience is a non-clay based ceramic displaying surface vitrification which creates a bright lustre of various blue-green colours. Having not been made from clay it is often not classed as pottery. It is called "Egyptian faience" to distinguish it from faience, the tin glazed pottery...
beads, a form of clay bead with a self-forming vitreous coating.
Common types of glass bead manufacture
Glass beads are usually categorized by the method used to manipulate the glass - 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 a type of 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 (61 m) 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.
The most common type of modern glass bead is the seed bead, a small type of bead typically less than 6 mm, traditionally monochrome, and manufactured in very large quantities.They are a modern example of mechanically-drawn glass beads. The micro-bead or "seed bead", are so called due to their tiny, regular size. Modern seed beads are extruded by machine and some, such as Miyuki delicas, look like small tubes.
Molded beads
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
. Thick rods are heated to molten and fed into a complex apparatus 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
Lampworking
Lampworking is a type of glasswork that uses a gas fueled torch to melt rods and tubes of clear and colored glass. Once in a molten state, the glass is formed by blowing and shaping with tools and hand movements. It is also known as flameworking or torchworking, as the modern practice no longer...
. 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 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 dual fuel torches, so `flameworked' is replacing the older term. Unlike a metalworking
Metalworking
Metalworking is the process of working with metals to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large ships and bridges to precise engine parts and delicate jewelry. It therefore includes a correspondingly wide range of skills,...
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, dichroicDichroism
Dichroism has two related but distinct meanings in optics. A dichroic material is either one which causes visible light to be split up into distinct beams of different wavelengths , or one in which light rays having different polarizations are absorbed by different amounts.The original meaning of...
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. If the glass is kept in the flame too long, the metallic coating will turn silver and burn off.
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 linear and twisting stripe patterns. No air is blown into the glass. These beads require a large scale glass furnaceFurnace
A furnace is a device used for heating. The name derives from Latin fornax, oven.In American English and Canadian English, the term furnace on its own is generally used to describe household heating systems based on a central furnace , and sometimes as a synonym for kiln, a device used in the...
and anneal
Annealing (glass)
Annealing is a process of slowly cooling glass to relieve internal stresses after it was formed. The process may be carried out in a temperature-controlled kiln known as a Lehr. Glass which has not been annealed is liable to crack or shatter when subjected to a relatively small temperature change...
ing kiln
Kiln
A kiln is a thermally insulated chamber, or oven, in which a controlled temperature regime is produced. Uses include the hardening, burning or drying of materials...
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.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 glassSoda-lime glass
Soda-lime glass, also called soda-lime-silica glass, is the most prevalent type of glass, used for windowpanes, and glass containers for beverages, food, and some commodity items...
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 an industry in beads molded from powdered glass. Also in Africa, Kiffa beads
Kiffa beads
Kiffa beads are rare powder glass beads named after the Mauritanian city of Kiffa, where French ethnologist R.Mauny documented them first in 1949....
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 pendant
Pendant
A pendant is a loose-hanging piece of jewellery, generally attached by a small loop to a necklace, when the ensemble may be known as a "pendant necklace". A pendant earring is an earring with a piece hanging down. In modern French "pendant" is the gerund form of “hanging”...
s and cabochon
Cabochon
A cabochon , from the Middle French caboche , is a gemstone which has been shaped and polished as opposed to faceted. The resulting form is usually a convex top with a flat bottom. Cutting en cabochon is usually applied to opaque gems, while faceting is usually applied to transparent stones...
s are more typical. Lampwork (and other) beads can be painted with glass paints.