Air-twist Glass Stem

Air-twist Glass Stem - (Glass) Air twist stems were an English glass-making development that dates from the 1730s and followed in the 1740s by the opaque white enamel twist. Air twist stems are made by incorporating bubbles of air into a gather or mass of hot glass, which is then quickly twisted and pulled, the elongated bubbles thus forming corkscrew air lines inside the stem. In later examples the stem was made separately, still on the principle of the extended air bubble, being cut from long lengths; later again, from about 1750, a molded process brought with it much greater uniformity in the spiral and allowed for compound twists of considerable variety. When it cools slightly the whole mass is taken out of the mould and reheated and covered with another coating of clear glass. This is drawn out and twisted until it reaches the required thickness.