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FAQs
Everything you have always wanted to know about glass
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What are the main components of glass? In what ratio are the main components mixed?
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about 60 parts sand = 24%
about 180 parts potassium carbonate = 74%
about 5 parts lime/chalk = 2%
according to one of the first formulations handed down from Assyria (about 640 BC)
Additives, metals and rare earths are used to obtain colouring and other properties
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How is glass produced?
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Glass is melted in vats with fireproof cladding, which are heated by oil, gas or electricity, and then
a) drawn, rolled (flat glass)
b) pressed, blown (hollow glass)
and, if necessary, subjected to further processing:
a) coated
b) imprinted
c) polished
d) drilled
e) faceted
f) frosted
g) tempered/pre-stressed
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How is coloured glass made?
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Glass that is coloured throughout can be produced by adding colouring materials, subsequent coloured coating or transparent imprinting is also possible.
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How is opal glass made?
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Opal glass is made by frosting clear glass, or made as frosted translucent glass or as clear glass with white screen printing.
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At what temperatures does glass begin to melt?
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Depending on the type of glass and on the glass batch composition the melting temperature is between approximately 1000 °C and 1600 °C (1832 °F and 2912 °F).
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When was glass first produced?
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Historically, glass production is known to have existed in ancient Egypt around 8000 BC, as well as in Mesopotamia and Mycenaea, China and Northern Tyrol.
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Why does glass protect against UV rays?
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Special glass or vaporised glass has a blocking filter in the UV range, which reduces or blocks the penetration of UV rays.
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How many different types of glass are available from SCHOTT?
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SCHOTT manufactures over 50,000 different articles with over 400 types of glass.
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How is glass cut?
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Glass is
a) mechanically scored with a diamond cutting wheel and then broken along the scored edge (flat glass)
b) thermally heated with a pointed gas flame at the desired edge and then quenched with a cold water spray, so that an exact breaking edge is created, which is thermally polished (hollow glass)
c) or by laser beam which precisely heats a specific line on the glass followed by a cold jet of air or an air/liquid mixture. These thermally induced tensions cause a precise fissuring of the glass. The result are cutting edges of the highest quality.
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In which areas are fibre optics used?
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- Traffic control technology (e.g., as traffic light signal transmitters)
- Medicine (e.g., as endoscopes)
- Biology (as cold light sources)
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Why are fibre optics particularly safe and particularly protective (e.g., for items in display cases)?
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Cold light through fibre optic lighting offers the advantage that valuable items in display cases are not heated and thus do not oxidise, dry out or turn yellow.
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How are ceramics produced from glass?
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A glass specially mixed with nucleus formers and melted for ceramisation is ceramised in a time/temperature process, at the end of which a mixed glass/crystal structure is created, which has the desired qualities, e.g., of a cooking surface.
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How long does glass need to cool?
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To prevent stresses in the material, glass has to be brought slowly to the ambient temperature. This is done in a time-controlled cooling oven. Depending on the quantity/type of glass, this "cooling time" - which actually is a controlled "heating reduction" - lies in the range of hours to months.
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What is the temperature of the cooling ovens?
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At the start of the process, "cooling ovens" have a temperature level corresponding to the production temperature/forming temperature, and at the end of the process, that of the ambient temperature. This is an individual temperature/time profile dependent on the product/type of glass.
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What is cast glass?
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Cast glass designates a family of glass produced in a casting production process. It includes raw glass, figured glass, horticultural cast glass, wire-reinforced glass and wire-reinforced figured glass. It is also possible to produce coloured cast glass.
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What is flashed opal glass and what is it used for?
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Clear flat glass, which is coated and melted together with a thin opal glass (white) during drawing, is called flashed opal glass. Covers for lighting units for glare-free lighting, display cases and indicator glasses in instruments are only some of the applications.
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What do we mean by the term processed flat glass?
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Processed flat glass is float glass, which subsequently can be:
· cut
· drilled
· edge-trimmed
· faceted
· imprinted
· coated
· pre-stressed/tempered
· sandwich-glued/jointed
and thus can satisfy the various additional requirements.
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How are mirrors produced?
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Mirrors are produced by coating the rear side of flat glass with:
· silver
· copper
· or other reflecting materials.
The reflecting layer is additionally protected and lacquered with a coating.
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How can glass be coated?
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The coating of glass surfaces, in accordance with state-of-the-art processes, ensures even the most complex coating. This plays a great part in glass lenses for eyeglasses, display window glass, decorative glass.
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Contact
SCHOTT UK Ltd
Sales Office Drummond Road Astonfields Industrial Estate Stafford ST16 3EL United Kingdom
 | +44 (0)1785 223166 |
 | +44 (0)1785 223522 |
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