Showing posts with label Annealed. Show all posts
Showing posts with label Annealed. Show all posts

Wednesday, December 30, 2009

Patterned glass


Patterned glass is a kind of decorative translucent glass with embossed patterns on one or both surfaces. Pattern Glass or Decorative Glass or Rolled Glass is generally used where privacy or obscurity is desired but light transmission is still important. With the special property of decoration, patterned glass can allow light to pass through, at the same time, it can also prevent clear view. Usually it transmits only slightly less light than clear glass.

Patterned glass is not-perfectly-smooth structure with different patterns impressed on it. The depth, size and shape of the patterns largely determine the magnitude and direction of reflection.

Basically patterned glass has a pattern impressed on one side of the glass which prevents someone from seeing though it, for privacy. Pattern glass can also be ordered in various tints as well. A common application of this sort is when used in privacy walls to separate one room from another.

Rolled Pattern glasses are available in a wide variety of patterns, to add the perfect complement to many interior designs. Heavy patterned glasses provide added strength and support, and are a fast-growing product category. According to customers' requirements, patterned glass can be cut, ground, drilled, tempered, laminated, etc.

Production

Patterned glass is made with a rolled glass process. All rolled patterned glass begins as a batch of materials, including silica sand, soda, and lime. These materials are melted together in a tank, and then the molten glass mixture is fed onto a machine slab. The glass flows under a refractory gate which controls glass volume and speed then moves between two counter-rotating, water-cooled rollers. One of these rollers is embossed, imprinting a distinct pattern onto the soft surface of the glass while the other roller is smooth.

The result is a piece of glass that is patterned and textured on one side, while smooth on the reverse. The distance between the two rollers determines the ultimate thickness of the glass. After it moves between the rollers, patterned glass is annealed or cooled slowly in order to remove any residual stresses. Rolled patterned glass can then be cut into standard sizes or cut into customized sizes for a specific customer application. The glass is then inventoried and ready for delivery.

Applications

Rolled glasses are used in commercial, residential, and specialty applications. End uses include shower doors and tub enclosures including frameless shower doors interior partitions, translucent door and window treatments, foyers and vestibules, patio furniture, shelving, decorative furniture, and lighting fixtures. Comprehensive range of soft natural colours compliments and harmonizes with modern building materials to provide an exciting and different look to new and existing buildings. Pattern glasses are available in large amount of patterns. Patterned glass is most often found in bathroom windows.

Patterned glass is applied to all kinds of public and private places, such as office, meeting room, hotel, hospital, bath room, washroom, etc. It is also widely used as glass table, glass shaft and lampshade and so on. Mainly used in interior partitions, interior design, decorations, street furniture etc.

Monday, December 21, 2009

Fused Glass


Fusing glass in a kiln is a fascinating technique that enables artists to create unique and breathtaking designs in glass. Fused glass is also referred to as kiln-formed glass, art glass fusion and warm glass. The “warm” of warm glass is between 1,100 and 1,700 degrees Fahrenheit (600 and 925 degrees Celsius). At these temperatures, glass softens enough that when pieces of glass are heated and pressed together, they will fuse into a single seamless piece. This is the underlying principle behind glass fusing.

Glass Fusing

Glass fusing is the process of using a kiln to join together pieces of glass. If you apply heat to glass, it will soften. If you continue to apply heat, the glass will become more fluid and flow together. Two or more pieces of glass will stick to each other. When the right kind of glass is heated and then cooled properly, the resulting fused glass piece will be solid and unbroken.

Fused glass is normally fired (heat-processed) in a kiln at a range of high temperatures from 593 °C (1,099 °F) to 816 °C (1,501 °F). There are 3 main distinctions for temperature application and the resulting effect on the glass. They are as follows:

1. Slumping
2. Tack fusing
3. Full fusing

1. Slumping

Firing in the lower ranges of these temperatures 593–677 °C (1,099–1,251 °F) is called slumping. Slumping is a categorical description of an area of techniques for the formation of glass by applying heat to the point where the glass becomes plastic. The increasing fluidity of the glass with temperature causes the glass to 'slump' into the mould under the force of gravity. Glass is most commonly heated in an oven, often using glass in a sheet form and “slumping” it over a form or into a mould.

Moulds are generally made of high temperature plaster, clay coated with plaster or another release agent, graphite, sand mixed with a bonding agent, steel, or other materials. At the point where the glass has achieved the desired form the heat is quickly vented and the temperature reduced to prevent further movement of the glass and then it is stabilized at its respective annealing temperature and annealed.

2. Tack Fusing

Tack Fusing Glass refers to the effect that is obtained when two or more pieces of glass are heated to approximately 1350 to 1375 degrees F. This temperature range will result in any pieces of glass that are in contact with each other fusing together, while still allowing each piece to retain its' original shape, size and thickness.

3. Full Fusing

Several pieces of glass fused into a single finished piece of uniform thickness by heating them to somewhere between 1450 and 1475 degrees F is known as Full fusing. At these temperatures your glass will have melted enough to combine and flow together into a single piece of fused glass. This piece may be a finished piece or a starting point from which you cold work, cut or reshape the piece prior to another fusing.

Techniques

Most contemporary fusing methods involve stacking, or layering thin sheets of glass, often using different colors to create patterns or simple images. The stack is then placed inside the kiln (which is almost always electric, but can be heated by gas or wood) and then heated through a series of ramps (rapid heating cycles) and soaks (holding the temperature at a specific point) until the separate pieces begin to bond together. The longer the kiln is held at the maximum temperature the more thoroughly the stack will fuse, eventually softening and rounding the edges of the original shape.

Once the desired effect has been achieved at the maximum desired temperature, the kiln temperature will be brought down quickly through the temperature range of 815 °C (1,499 °F) to 573 °C (1,063 °F) in order to avoid devitrification. It is then allowed to cool slowly over a specified time, soaking at specified temperature ranges which are essential to the annealing process. This prevents uneven cooling and breakage and produces a strong finished product. This cooling takes place normally for a period of 10–12 hours in 3 stages.

The first stage- the rapid cool period is meant to place the glass into the upper end of the annealing range 516 °C (961 °F). The second stage- the anneal soak at 516 °C (961 °F) is meant to equalize the temperature at the core and the surface of the glass at 516 °C (961 °F) relieving the stress between those areas. The last stage, once all areas have had time to reach a consistent temperature, is the final journey to room temperature. The kiln is slowly brought down over the course of 2 hours to 371 °C (700 °F), soaked for 2 hours at 371 °C (700 °F), down again to 260 °C (500 °F) which ends the firing schedule. The glass will remain in the unopened kiln until the pyrometer reads room temperature.

Tuesday, November 24, 2009

Glass Types

Flat Glass

Flat glass is the basic material that goes into all types of glass that we see (and see through) every day: All flat glass is made in the form of flat sheets. But some of it, such as that used in automobile windshields, is reheated and sagged (curved) over moulds. It is used to make windscreens and windows for automobiles and transport, and windows and façades for houses and buildings. It is also used, in much smaller quantities, for many other applications like interior fittings and decoration, furniture, "street furniture" (like for bus stops), appliances and electronics, solar energy equipment, and others.

Annealed glass

Annealed glass is the basic flat glass product that is the first result of the float process. It is the common glass that tends to break into large, jagged shards. It is used in some end products -- often in double-glazed windows, for example. It is also the starting material that is turned into more advanced products through further processing such as laminating, toughening, coating, etc.

Laminated Glass

Laminated glass is made of two or more layers of glass with one or more "interlayer’s" of polymeric material bonded between the glass layers. Laminated glass is produced using one of two methods:
  1. Poly Vinyl Butyral (PVB) laminated glass is produced using heat and pressure to sandwich a thin layer of PVB between layers of glass. On occasion, other polymers such as Ethyl Vinyl Acetate (EVA) or Polyurethane (PU) are used. This is the most common method.
  2. For special applications, Cast in Place (CIP) laminated glass is made by pouring a resin into the space between two sheets of glass that are held parallel and very close to each other.
Laminated glass offers many advantages. Safety and security are the best-known of these -- rather than shattering on impact, laminated glass is held together by the interlayer, reducing the safety hazard associated with shattered glass fragments, as well as, to some degree, the security risks associated with easy penetration. But the interlayer also provides a way to apply several other technologies and benefits, such as coloring, sound dampening, resistance to fire, ultraviolet filtering, and other technologies that can be embedded in or with the interlayer.
Laminated glass is used extensively in building and housing products and in the automotive and transport industries.

Alarm Glass

This is a special laminated glass designed and manufactured for security purposes. The inter-layer is embedded with a very thin wire and then “sandwiched” between two or more sheets of glass. The wire forms an electrical circuit which activates an alarm when the glass is forced.

Reflective Glass

Reflective Glass is an ordinary float glass with a metallic coating to reduce solar heat. This special metallic coating also produces a mirror effect, preventing the subject from seeing through the glass. It is mainly used in façades. Reflective glasses are mainly manufactured by two different process such as Production Pyrolitic (On-Line) and Vacuum (magnetron) Process (off-line).

Anti-reflective Glass

This is float glass with a specially-designed coating which reflects a very low percentage of light. It offers maximum transparency and optical clarity, allowing optimum viewing through the glass at all times. The clarity of vision makes anti-reflective glass suitable for all applications where glass should be transparent such as exteriors, shop-fronts, commercial frontages and glazing where vision is important, particularly at nighttime. This glass can also be used in interiors for high quality picture framing, display cabinets, interior display windows and dividing screens.

Fire-resistant Glass

This can be classified into two categories:
  1. Heat-transmitting Glass: 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 contains flames and inflammable gas for a short period of time but does not prevent the transmission of heat to the other side of the glazing. These include wired glass and reinforced laminated glass. This type of glasses is widely used in cookware and other household equipment, and in many types of industrial gear.
  2. Fire-insulating Glass: This contains flames and inflammable gas for a longer period of time and prevents not only the transmission of flames and smoke, but also of heat to the other side of glazing
Tempered (toughened) Glass

Toughened glass is made from annealed glass treated with a thermal tempering process. A sheet of annealed glass is heated to above its "annealing point" of 600 °C; its surfaces are then rapidly cooled while the inner portion of the glass remains hotter. The different cooling rates between the surface and the inside of the glass produces different physical properties, resulting in compressive stresses in the surface balanced by tensile stresses in the body of the glass.
These counteracting stresses give toughened glass its increased mechanical resistance to breakage, and are also, when it does break, what cause it to produce regular, small, typically square fragments rather than long, dangerous shards that are far more likely to lead to injuries. Toughened glass also has an increased resistance to breakage as a result of stresses caused by different temperatures within a pane.

This type of glass is mainly intended for glass façades, sliding doors, building entrances, bath and shower enclosures and other purposes that require superior strength and safety.

Low-emission Glass

Glass that has a low-emissivity coating applied to it in order to control heat transfer through windows. Windows manufactured with low-E coatings typically cost about 10–15% more than regular windows, but they reduce energy loss by as much as 30–50%.

A low-E coating is a microscopically thin, virtually invisible, metal or metallic oxide layer deposited directly on the surface of one or more of the panes of glass. The low-E coating reduces the infrared radiation from a warm pane of glass to a cooler pane, thereby lowering the U-factor of the window. Different types of low-E coatings have been designed to allow for high solar gain, moderate solar gain, or low solar gain. A low-E coating can also reduce a window's visible transmittance unless you use one that's spectrally selective.

Window manufacturers apply low-E coatings in either soft or hard coats. Soft low-E coatings degrade when exposed to air and moisture, are easily damaged, and have a limited shelf life. Therefore, manufacturers carefully apply them in insulated multiple-pane windows. Hard low-E coatings, on the other hand, are more durable and can be used in add-on (retrofit) applications. The energy performance of hard-coat, low-E films is slightly poorer than that of soft-coat films.

Self-cleaning glass

Self-cleaning glass is a specific type of glass with a surface which keeps itself free of dirt and grime through natural processes. The first self-cleaning glass was based on a thin film titanium dioxide coating. The glass cleans itself in two stages.

The "photo catalytic" stage of the process breaks down the organic dirt on the glass using ultraviolet light (reflected from the glass)even on overcast days and makes the glass hydrophilic (normally glass is hydrophobic). During the following "hydrophilic" stage rain washes away the dirt, leaving almost no streaks, because hydrophilic glass spreads the water evenly over its surface.

Bullet-proof glass

Bullet-proof 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.

Body-tinted glass

Body-tinted glass is a normal float-clear glass into whose melt colorants are added for tinting and solar-radiation absorption properties. This reduces heat penetration in buildings. Coloured glass is an important architectural element for the exterior appearance of façades. Body-tinted Glass is also used in interior decoration.

Production is the same as in float glass production. The only variation is the colorants mixed at the beginning with the standard raw materials. Different additives may produce differently colored glasses.

Sand Blasted Glass

This is produced by spraying sand at high velocities over the surface of the glass. This gives the glass a translucent surface, which is usually rougher than that obtained by etching. During sandblasting, only the areas that are to remain transparent are masked for protection. The depth and degree of the translucency of the sand-blasted finishing vary with the force and type of sand used. Sand-blasted glass can be used in numerous interior design applications in both residential and commercial settings: doors, shower screens, partitions and interior screens, furniture, etc.

Acid-etched Glass

It is produced by acid etching one side of float glass. Acid-etched glass has a distinctive, uniformly smooth and satin-like appearance. Acid-etched glass admits light while providing softening and vision control. It can be used in both residential and commercial settings (doors, shower screens, furniture, wall paneling, etc.).

Wire glass

Wired glass is a product in which a wire mesh has been inserted during production. It has an impact resistance similar to that of normal glass, but in case of breakage, the mesh retains the pieces of glass. This product is traditionally accepted as low-cost fire glass. In the production of wire glass, a steel wire mesh is sandwiched between two separate ribbons of semi-molten glass, and then passed through a pair of metal rollers which squeeze the "sandwich of glass and wire" together.

Stained glass

The term stained glass can refer to the material of colored glass or the craft of working with it. Although traditionally made in flat panels and used as windows, the creations of modern stained glass artists also include three-dimensional structures and sculpture.

"Stained glass" has been applied almost exclusively to the windows of churches, cathedrals, chapels, and other significant buildings.

Fiber glass

Fiberglass, (also called fibreglass and glass fiber), is material made from extremely fine fibers of glass. It is used as a reinforcing agent for many polymer products; the resulting composite material, properly known as fiber-reinforced polymer (FRP) or glass-reinforced plastic (GRP), is called "fiberglass" in popular usage.

Bent Glass

This is a normal glass that is curved with a special process. It can be used for external sites such as facades, shop fronts and panoramic lifts. This glass is also commonly used for internal sites for showcases, shower doors and refrigerator cabinets

Patterned Glass

This glass does not have a perfectly-smooth surface but rather has different patterns impressed on it. The most common method for producing patterned glass is to pass heated glass (usually just after it exits the furnace where it is made) between rollers whose surfaces contain the negative relief of the desired pattern(s). The depth, size and shape of the patterns largely determine the magnitude and direction of reflection. Patterned glass usually transmits only slightly less light than clear glass. It can be used for a variety of applications such as interior design and decorations, furniture, windows and street furniture.

Enamelled Glass

This is tempered or heat-strengthened glass, one face of which is covered, either partially or totally, with mineral pigments. In addition to its decorative function, enameled glass is also a solar ray controller. Enamelled glass is used for glazing and for cladding facades and roofs. It can be assembled into laminated glass or glazed insulation

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.

Soda Glass

Soda Glass is the cheapest & most common glass. It is prepared by fusing soda ash, sand, limestone. It is also called soft glass. It fuses at comparatively low temperatures. The major disadvantage of using this glass is that it is brittle & breaks easily. It cracks when subjected to sudden changes of temperature. Soda glass is used for the manufacture of window glass, glass mirrors, common glassware etc. it is easily attacked by chemicals.

Hard Glass

Hard Glass is obtained by fusing potassium carbonate & limestone. It is used for making hard glass apparatus. It is more resistant to the action of acids.

Lead Crystal Glass

Lead Crystal Glass is made from potassium carbonate, lead oxide & sand. Lead glass has high refractive index. It, therefore, sparkles & is used for making expensive glass ware. The surface of lead glass objects is often cut into decorative patterns to reflect light. Cut glass show extraordinary sparkle.

Pyrex Glass

It is made by fusing a mixture of sand, lime, borax (Na2B4O7.10H2O) & alkali carbonates. It has good chemical laboratory apparatus, ampoules, pharmaceutical containers, etc. In home, it is familiar with oven ware.

Optical Glass

It is specially made so as to be free of strains & defects. It is used for making lenses for spectacles, microscopes, cameras, telescopes & other optical instruments.

Colored Structural Glass

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

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

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.

Photochromic 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.