Glass is transparent, lustrous and brittle material made of mixture of silica or pure fine sand, soda or potash and some other ingredients. The mixture is heated in furnace above 1300 degree where it forms molten glass. It is then shaped and cooled slowly in oven as it passes on conveyor belt. This process is called annealing. It finds diverse applications in hotels.
Types of Glass
- Lead Crystal Glass: this contains lead oxide which produces a lustrous glass, soft enough to enable the outer surface to be cut away into attractive design. It is expensive and used in bowls, drinking glasses, vases, etc.
- Soda Lime Glass: this contains soda ash & limestone and is much cheaper to produce than lead crystal. It is used for general purpose—bottles, windows, pictures, mirrors, etc.
- Borosilicate Glass: this contains borax which enables the glass to withstand heat. Used for cookware and is referred to as flameproof glass.
- Silvered glass (for mirror) is made by coating one side of a glass panel with silver, followed by a coat of paint and a layer of stove enamel.
It can be classified according to usage:
- Flat Glass: is soda lime glass and used in making large flat panels.
- Sheet Glass: This needs polishing after annealing. Sheet glass used for windows is made from soda lime base. It may be textured so that light passes through but it is not transparent (Obscured glass) It may have incorporated wire in between (Obscured glass with wire).
- Float Glass: This type of glass does not require polishing after annealing. It is of better quality and finish then sheet glass.
2.Obscured Glass: It is basically a sheet glass that has a texture on one side so that visibility is restricted but the light passes through. Generally used in bathrooms.
3.Fibre Glass: It is manufactured in shape of textile fibre or as sheets of plastic. These can be moulded and are used for sanitary ware, furniture and wall panels. It is fire proof, impermeable and resistant to damage by pests, sunlight and air.
4.Hollow Glassware: Made by moulding or blowing hot glass into iron or wood casts. The moulds may have patterns which give the final object various effects.
5.Safety Glass: This kind of glass is used in places that require good safety and protection from easy and frequent damage or for security related applications.
- Obscured glass with wire: Wire is rolled into the obscured glass that holds the pieces as it gets broken.
- Toughened Glass: It is made by heating the glass to high temperature and then cooling it rapidly. As a result skin forms which if the glass breaks will cause the pieces to shatter into tiny harmless fragments.
- Laminated Glass: It consist of thin sheet of plastic sandwiched between two sheets of glass.
- Toughened Glass with lamination: Combination of the two glasses above.
6.Cut Glass: This is made by hand cutting glass articles using abrasive copper wheels that rotate at high speed. Cut glass is polished by treating the glass by acid. The grooves created emit rainbow-colored reflections. This glass is expensive and used for chandeliers, decanters, vases and quality table glassware.
Glass Cleaning:-
- Flat Glass: Dusting should be done daily by a lint free cloth. Light soiling and greasy marks should be removed using a solution of vinegar and water (1:1). Window squeegee may be used for larger areas and quick cleaning after dipping it in mild detergent solution or glass cleaners. Newspaper contains effective solvent which can be used at last to buff the glass dry.
- Hollow glassware: Textured or engraved glass is cleaned with a nylon brush. Stained vases can be cleaned using a mixture of crushed shells (as an abrasive for textured glassware like wine decanters), synthetic detergent (less alkaline) and warm water. For jars and bottles a mixture of construction sand and water can also be used to remove discoloration. To remove lime deposits caused due to hard water soak the article in distilled water for an hour, scrub with a nylon scrubber and synthetic detergent solution and rinse with water.
- Chandliers: Chandeliers are delicate, expensive and therefore difficult to maintain. Cleaning them is a laborious and time consuming process. For cleaning they are brought down and dismantled piece by piece dipped in a warm solution of mild detergent. Each piece is gently scrubbed by a nylon scrubber and rinsed in warm water. Second rinsing is done in a mixture of one teaspoon liquid ammonia in 2.5 ltrs of water. This is results in a brilliant sparkle. Alternate method is to use an upholstery shampooing machine. The machine sprays a detergent solution that cleans glass pieces by pressure and the water is collected in a basin. SOLVENT BASED CLEANER.
Maintaining glass surfaces:
- Glass surfaces are easily marked & easily damaged
- Require frequent attention & should be treated accordingly
- Damp or dry dusting with a lint free duster or scrim for glass cleaning
- Light soiling & grease marks can be removed by wiping with a solution of equal quantities of vinegar and water
- More stubborn marks can be removed using methylated spirit
- Newspaper prints contain solvent & can be used to remove soiling from windows
- Textured or engraved glass can be cleaned with a soft brush
- Glass polish can also be used, care should be taken polish is removed while buffing
- Stained decanters & vases can be cleaned with vinegar, water & potato pieces
- Use of abrasives should be avoided
- Mirror should be cleaned with damp duster, care should be taken not to dampen the backing.
