Glass becomes fully molten at 2,000-2,500*C, depending on the glass type. Hot glass work differs from both cold and warm glass in that the artist works directly with the molten material, using a variety of tools to hold and manipulate the molten glass, as touching and holding it directly is out of the question.
The liquid glass is shaped by pouring it into a mould, usually made of plaster of paris, and placed in a hot kiln to slowly cool over many hours as the temperature is gradually lowered. Glass is very sensitive to sudden temperature differences, as anyone who has ever tried pouring boiling water into a non-pyrex glass will know.
At its simplest, glass blowing involves dipping a blowpipe into a furnace of molten glass to gather a blob of glass at the end. The molten blob is then blown out into a bubble. The bubble can be enlarged by being dipped and re-blown multiple times. It can be stretched, twisted, flattened or re-blown into a mould to make an almost infinite variety of shapes.
Lampwork differs from glass blowing in that the artist does not start with a furnace of molten glass, but melts the tips of solid glass rods in a flame, using the molten material to create beads, pendants, paperweights and small sculptures. The term “lampwork” comes from the oil lamps – “lampe”, used by Venetian and Murano craftsmen from the 14th century onwards. Although modern lampwork artists now use gas-fired torches, they still retain a strong connection with Venice and Murano. Much of the glass used for lampworking is made in Murano, and many of the English technical terms are an Anglicised version of the original Italian. The pictures below show the lampwork process.