Especialidades JA/Trabajos en vidrio/Respuestas
Nivel de destreza
1
Año
1970
Version
27.11.2024
Autoridad de aprobación
Asociación General
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Cuando las personas hablan de vidrio, normalmente se refieren a una sustancia transparente y brillante que se rompe con bastante facilidad. Pueden pensar que el vidrio en las ventanas y el vidrio usado en las gafas son el mismo material. En realidad, no lo son. Hay muchos tipos de vidrio.
Vidrio plano se usa principalmente en ventanas. También se usa en espejos, separadores de habitaciones y algunos tipos de muebles. Todo el vidrio plano está hecho en forma de láminas planas. Pero algunos, como la que se usa en los parabrisas de automóviles, se recalienta y se curva sobre los moldes.
Los contenedores de vidrio se utilizan para envasar alimentos, bebidas, medicamentos, productos químicos y cosméticos. Los frascos y botellas de vidrio se fabrican en una amplia variedad de formas, tamaños y colores. Muchos son para usos comunes, como botellas de refrescos o frascos para enlatar en el hogar. Otros están hechos de fórmulas de vidrio especiales para asegurarse de que no haya contaminación o deterioro del plasma sanguíneo, sueros y sustancias químicas almacenadas en ellos.
El vidrio óptico se usa en lentes, microscopios, telescopios, lentes de cámara y muchos instrumentos para fábricas y laboratorios. Las materias primas deben ser puras para que el vidrio se pueda hacer casi perfecto. El cuidado requerido para producir vidrio óptico lo hace costoso en comparación con otros tipos de vidrio.
Fiberglass consists of fine but solid rods of glass, each of which may be less than one-twentieth the width of a human hair. These tiny glass fibers can be loosely packed together in a woollike mass that can serve as heat insulation. They also can be used like wool or cotton fibers to make glass yarn, tape, cloth, and mats. Fiberglass has many other uses. It is used for electrical insulation, chemical filtration, and firefighters' suits. Combined with plastics, fiberglass can be used for airplane wings and bodies, automobile bodies, and boat hulls. Fiberglass is a popular curtain material because it is fire-resistant and washable.
Laminated safety glass is a “sandwich” made by combining alternate layers of flat glass and plastics. The outside layer of glass may break when struck by an object, but the plastic layer is elastic and so it stretches. The plastic holds the broken pieces of glass together and keeps them from flying in all directions. Laminated glass is used where broken glass might cause serious injuries, as in automobile windshields.
Bullet-resisting glass is thick, multilayer laminated glass. This glass can stop even heavy-caliber bullets at close range. Bullet-resisting glass is heavy enough to absorb the energy of the bullet, and the several plastic layers hold the shattered fragments together. Such glass is used in bank teller windows and in windshields for military tanks, aircraft, and special automobiles.
Tempered safety glass, unlike laminated glass, is a single piece that has been given a special heat treatment. It looks, feels, and weighs the same as ordinary glass. But it can be several times stronger. Tempered glass is used widely for all-glass doors in stores, side and rear windows of automobiles, and basketball backboards, and for other special purposes. It is hard to break even when hit with a hammer. When it does break, the whole piece of glass collapses into small, dull-edged fragments.
Colored structural glass is a heavy plate glass, available in many colors. It is used in buildings as an exterior facing, and for interior walls, partitions, and tabletops.
Opal glass has small particles in the body of the glass that disperse the light passing through it, making the glass appear milky. The ingredients necessary to produce opal glass include fluorides (chemical compounds containing fluorine). This glass is widely used in lighting fixtures and for tableware.
Foam glass, when it is cut, looks like a black honeycomb. It is filled with many tiny cells of gas. Each cell is surrounded and sealed off from the others by thin walls of glass. Foam glass is so light that it floats on water. It is widely used as a heat insulator in buildings, on steam pipes, and on chemical equipment. Foam glass can be cut into various shapes with a saw.
Glass building blocks are made from two hollow half-sections sealed together at a high temperature. Glass building blocks are good insulators against heat or cold because of the dead-air space inside. The blocks are laid like bricks to make walls and other structures.
Heat-resistant glass is high in silica and usually contains boric oxide. It expands little when heated, so it can withstand great temperature changes without cracking. This quality is necessary in cookware and other household equipment, and in many types of industrial gear.
Laboratory glassware includes beakers, flasks, test tubes, and special chemical apparatus. It is made from heat-resistant glass to withstand severe heat shock (rapid change in temperature). This glass is also much more resistant to chemical attack than ordinary glass.
Glass for electrical uses. Glass has properties that make it useful in electrical applications: ability to resist heat, resistance to the flow of electric current, and ability to seal tightly to metals without cracking. Because of these properties, glass is used in electric light bulbs and for picture tubes in television sets.
Glass optical fibers are glass fibers used to transmit information as pulses of light. Thin, extremely pure optical fibers are used to carry telephone and television signals and digital (numeric) data over long distances. Glass optical fibers are also used in control board displays and in medical instruments.
Glass tubing is used to make fluorescent lights, neon signs, glass piping, and chemical apparatus. Glass tubing is made from many kinds of glass and in many sizes.
Glass-ceramics are strong materials made by heating glass to rearrange some of its atoms into regular patterns. These partially crystalline materials can withstand high temperatures, sudden changes in temperature, and chemical attacks better than ordinary glass can. They are used in a variety of products, including heat-resistant cookware, turbine engines, electronic equipment, and nose cones of guided missiles. Glass-ceramics have such trade names as Pyroceram, Cervit, and Hercuvit.
Radiation-absorbing and radiation-transmitting glass can transmit, modify, or block heat, light, X rays, and other types of radiant energy. For example, ultraviolet glass absorbs the ultraviolet rays of the sun but transmits visible light. Other glass transmits heat rays freely but passes little visible light. Polarized glass cuts out the glare of brilliant light. One-way glass is specially coated so that a person can look through a window without being seen from the other side.
Laser glass is an optical glass containing small amounts of substances that enable the glass to generate laser beams efficiently. Such glass is used as the active medium in solid-state lasers, a type of laser that sends light out through crystals or glass (One substance commonly used in laser glass is the element neodymium. Researchers are using glass lasers in an attempt to harness nuclear fusion (the joining of atomic nuclei) as a source of commercially useful amounts of energy. In their experiments, powerful glass lasers heat hydrogen atoms until hydrogen nuclei fuse, releasing large amounts of energy.
"Invisible glass" is used principally for coated camera lenses and eyeglasses. The coating is a chemical film that decreases the normal loss of light by reflection. This allows more light to pass through the glass.
Photochromic glass darkens when exposed to ultraviolet rays and clears up when the rays are removed. Photochromic glass is used for windows, sunglasses, and instrument controls.
Photosensitive glass can be exposed to ultraviolet light and to heat so that any pattern or photograph can be reproduced within the body of the glass itself. Because the photographic print then becomes an actual part of the glass, it will last as long as the glass itself.
Photochemical glass is a special composition of photosensitive glass that can be cut by acid. Any design can be reproduced on the glass from a photographic film. Then when the glass is dipped in acid, the exposed areas are eaten away, leaving the design in the glass in three dimensions. By this means, lacelike glass patterns can be made.
Heavy metal fluoride glass is an extremely transparent glass being developed for use in optical fibers that transmit infrared rays. Infrared rays are much like light waves but are invisible to the human eye. In optical fibers, infrared light transmits better over distance than visible light does.
Chalcogenide glass is made up of elements from the chalcogen group, including selenium, sulfur, and tellurium. The glass is transparent to infrared light and is useful as a semiconductor in some electronic devices. Chalcogenide glass fibers are a component of devices used to perform laser surgery.
Sol-Gel glass can be used as a protective coating on certain solar collectors or as an insulating material. It is also used to make short, thick tubes that are drawn into optical fibers. To make Sol-Gel glass, workers dissolve the ingredients in a liquid. They then heat the liquid. The liquid evaporates, leaving behind small particles of glass. Heating these particles fuses (joins) them to form a solid piece of glass. The temperatures involved in Sol-Gel processes are often lower than those needed to make ordinary glass.
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See the steps in the next requirement. The glass work will be more interesting if you use multiple colors. Clear and white are colors too. Consider thrift stores as a source of cheap colored glass.
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There are a variety of ways to make a picture with glass. Some people arrange beach glass in a frame, gluing the pieces down. Some people melt glass together (Color Me Mine now offers this kind of project). You might like to try stained glass. Pinterest is a great place to search for ideas. Here we provide instructions for one style pf project.
Grouted Mosaic
- Step 1. Decide on a project
- If you have a tabletop that is damaged or needs refinishing, you could cover it in glass mosaic instead. Kitchen tables, coffee tables, end tables, nightstands, and occasional tables all look great with glass mosaic tops. An old windowpane covered in glass mosaic makes a great alternative to stained glass, or you could cover a photo frame in glass mosaic as a smaller project. If you have a bathroom or kitchen floor that needs to be redone, you could cover it cheaply and attractively in tile mosaic.
- Step 2. Finding enough glass or tile for your project
- You can find it in many different places, and for fairly cheap if you are creative about it. If your project calls for clear glass, you can use colored bottles, vases, ashtrays, and other various pieces of clear, colored glass. If you want opaque glass, consider using old dishes and other unwanted glass or porcelain items. You may also be able to find broken tile for little or no money.
- Step 3. Break the glass for your project
- The goal is to create many random-shaped pieces that are large enough to work with. In other words, you don’t want to shatter the glass into bits. Hit each piece of glass with the hammer just once and take a look at the results before hitting it again.Once you have broken all of your glass into pieces, start arranging it on the surface that you are redoing. Of all the steps to making glass mosaics, this step requires the most time and planning. You will need to decide whether to create a picture or a pattern with your glass mosaic, or just arrange the pieces randomly.While you are doing this, keep in mind that the pieces don’t need to fit together perfectly, like a puzzle. In fact, there should be about an eighth of an inch of space between each piece, so that you have room for the grout when you get to that step.
- Step 4. Arrange the colors and the size according to your desires
- Step 5. Glue down each and every piece of glass
- The point of arranging the glass first, and then gluing it down is to make sure you get everything in the right place, so make sure you are done with the previous step before you start on this one.
- Step 6. Fill in all the spaces between the pieces of glass with grout
- Take the grout and be sure to fill every space completely. If the glass is still sharp, you will need to wear rubber dishwashing gloves to protect your hands. Once the spaces are all filled, you can use a damp towel to remove the grout from the tops of the pieces of glass. Once your glass mosaic is finished, be sure to let the glue and grout set for a while before using the piece, particularly if it is a table or a window hanging.
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India (Hindu Kingdoms)
Indigenous development of glass technology in South Asia may have begun in 1730 BCE. Evidence of this culture includes a red-brown glass bead along with a hoard of beads dating to that period, making it the earliest attested glass from the Indus Valley locations. Glass discovered from later sites dating from 600–300 BCE displays common color.
Chalcolithic evidence of glass has been found in Hastinapur, India. Some of the texts which mention glass in India are the Shatapatha Brahmana and Vinaya Pitaka. However, the first unmistakable evidence in large quantities, dating from the 3rd century BCE, has been uncovered from the archaeological site in takshashila, ancient India.
By the first century C.E., glass was being used for ornaments and casing in South Asia. Contact with the Greco-Roman world added newer techniques, and Indians artisans mastered several techniques of glass molding, decorating and coloring by the succeeding centuries.[41] The Satavahana period of India also produced short cylinders of composite glass, including those displaying a lemon yellow matrix covered with green glass.
Islamic world
The Arab poet al-Buhturi (820–897) described the clarity of such glass, "Its color hides the glass as if it is standing in it without a container."
Stained glass was also first produced by Muslim architects in Southwest Asia using colored glass rather than stone. In the 8th century, the Arab chemist Jabir ibn Hayyan (Geber) scientifically described 46 original recipes for producing colored glass in Kitab al-Durra al-Maknuna (The Book of the Hidden Pearl), in addition to 12 recipes inserted by al-Marrakishi in a later edition of the book.
By the 11th century, clear glass mirrors were being produced in Islamic Spain.
Medieval Europe
Glass objects from the 7th and 8th centuries have been found on the island of Torcello near Venice. These form an important link between Roman times and the later importance of that city in the production of the material. Around 1000 AD, an important technical breakthrough was made in Northern Europe when soda glass, produced from white pebbles and burnt vegetation was replaced by glass made from a much more readily available material: potash obtained from wood ashes. From this point on, northern glass differed significantly from that made in the Mediterranean area, where soda remained in common use.
Until the 12th century, stained glass – glass to which metallic or other impurities had been added for coloring – was not widely used.
The 11th century saw the emergence in Germany of new ways of making sheet glass by blowing spheres. The spheres were swung out to form cylinders and then cut while still hot, after which the sheets were flattened. This technique was perfected in 13th century Venice.
The Crown glass process was used up to the mid-19th century. In this process, the glassblower would spin approximately 9 pounds (4 kg) of molten glass at the end of a rod until it flattened into a disk approximately 5 feet (1.5 m) in diameter. The disk would then be cut into panes.
Murano glassmaking
The center for glassmaking from the 14th century was the island of Murano, which developed many new techniques and became the center of a lucrative export trade in dinnerware, mirrors, and other luxury items. What made Venetian Murano glass significantly different was that the local quartz pebbles were almost pure silica, and were ground into a fine clear sand that was combined with soda ash obtained from the Levant, for which the Venetians held the sole monopoly. The clearest and finest glass is tinted in two ways: firstly, a small or large amount of a natural coloring agent is ground and melted with the glass. Many of these coloring agents still exist today; for a list of coloring agents, see below. Black glass was called obsidianus after obsidian stone. A second method is apparently to produce a black glass which, when held to the light, will show the true color that this glass will give to another glass when used as a dye.
The Venetian ability to produce this superior form of glass resulted in a trade advantage over other glass producing lands. Murano’s reputation as a center for glassmaking was born when the Venetian Republic, fearing fire might burn down the city’s mostly wood buildings, ordered glassmakers to move their foundries to Murano in 1291. Murano's glassmakers were soon the island’s most prominent citizens. Glassmakers were not allowed to leave the Republic. Many took a risk and set up glass furnaces in surrounding cities and as far afield as England and the Netherlands.
References
Ahmad Y Hassan, Assessment of Kitab al-Durra al-Maknuna, History of Science and Technology in Islam. http://en.wikipedia.org/wiki/Glass
