What is Glass? – a query I’ve been asked many times during my lectures. The foremost aspect of glass is SILICA, which occurs naturally in extremely good abundance. The essential varieties are SAND, rose gold glass frames FLINT AND QUARTZ. When heated to a excessive sufficient temperature, they soften to form glass.
The heat from the primary atomic bomb at Los Alamos, New Mexico, turned a good deal of the floor of the desolate tract around the blast site into glass. Volcanic eruptions in which silica is gift, also can shape a dark herbal glass called OBSIDIAN.
Early glassmaking – The temperature required to soften silica (about 1800 degrees C) is higher than can be received in the primitive wooden-burning furnaces. Man-made glass most effective became viable by way of the discovery that soda ash or potash (acquired from burnt vegetable cloth) caused the silica to melt at 900-1100 ranges C.
The Mediterranean vicinity favoured soda ash and European nations potash. Natural tints in the glass are removed through the addition of nitre, manganese or arsenic. This turned into no longer a precise factor due to the fact the additions produced tints of their very own, explaining why there has been a extensive range of colors in early glass. Modern pure components imply that a consistently clear and colourless glass can be produced.
Molten glass is generally referred to as the METAL.
Additions of COPPER, COBALT, IRON, TIN and other materials produce BLUE, RED, GREEN, AMBER, WHITE OR PURPLE GLASS.
Methods of manufacture – Today, even the lowliest family has items of glass. It has turn out to be nearly customary in its use and the price range is good sized, from a much less than a pound consistent with glass, to many loads, or maybe lots of kilos, for one glass.
So how is it made? – Early glassmakers used MOULDING strategies. This lasted from about the 15th Century BC – 1St Century BC. Blowing was found during the 1st Century BC and via the 1st Century AD without a doubt every approach of manipulating and redecorating glass had been located – moulding, loose blowing, blowing right into a mould, slicing, engraving, enameling, gilding, overlaying with layers of colored glass, enclosing the decoration among layers of glass, millefiori and glass made to appear to be herbal stone. All these were practiced 2000 years in the past and feature reappeared at various times right down to the present.
Tools – The gear used in glassmaking have remained nearly unchanged for plenty centuries, especially due to the fact they’re so easy.
The essential gear are as follows:
BLOWPIPE – glass is accrued at the bulbous quit and by way of blowing down the pipe a form is produced.
CHAIR – the glass-blowers administrative center – a bench with flat fingers along which the blowpipe can be rolled to form the vessel. Confusingly, in a pitcher-works making hand-blown glass, it also refers to a crew of three or 4 guys. Thus the size of the manufacturing unit is reckoned by means of the quantity of chairs.
CLAPPERS – made from wooden and shaped instead like butter ‘pats’ – used to flatten a blob of molten glass right into a foot for a wine glass.
GADGET – a spring clip connected to an iron rod. Replaced the pontil iron in the 18th century and does now not produce a pontil mark.
MARVER – a flat iron plate, about 2-three toes square, with a smooth, extraordinarily polished surface. Molten glass has a plastic consistency and may be rolled on the marver for the duration of the blowing technique to clean and shape the glass.
PONTIL IRON – a solid steel rod. The quit is heated and applied to the bottom of the vessel being blown, to help it whilst the blowing pipe is reduce away.(while the pontil is eliminated, it produces a function mark called the PONTIL MARK on the base)