Plate glass is thick, good quality glass made in huge sheets for shop windows. It’s very smooth surface is made by floating the molten glass onto a bath of molten tin. Tin melts at a lower temperature than glass, so the glass begins to set on the tin and is then passed over rollers as it finishes cooling. The larger the bath of molten tin the larger the glass that can be made.
Plate glass, flat glass or sheet glass is a type of glass, initially produced in plane form, commonly used for windows, glass doors, transparent walls, and windscreens. For modern architectural and automotive applications, the flat glass is sometimes bent after production of the plane sheet. Flat glass stands in contrast to container glass (used for bottles, jars, cups) and glass fiber (used for thermal insulation, in fiberglass composites, and optical communication).
Flat glass has a higher magnesium oxide and sodium oxide content than container glass, and lower silica, calcium oxide, and aluminum oxide content. (From the lower soluble oxide content comes the better chemical durability of container glass against water, which is required especially for storage of beverages and food). Most flat glass is soda-lime glass, produced by the float glass process (1950s). Other processes for making flat glass include:
Scratches can occur on sheet glass from accidental causes. In glass trade terminology these include “block reek” produced in polishing, “runner-cut” or “over/under grind” caused by edge grinding, or a “sleek” or hairline scratch, as well as “crush” or “rub” on the surface.
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