Wednesday, 9 March 2011

History: Wound Glass Beads

The earliest bead making civilisations produced beads using the wound method, indeed it is one of the first ways in which glass beads were made. Ancient cultures, such as the Egyptians, heated a crucible of glass into which they dipped a mandrel. This technique is sometimes referred to as furnace winding, because the glass was first heated in a furnace. To form the shape of the bead the mandrel was rotated to allow the molten glass to move and create a rounded shape. The bead could be shaped whilst still on the mandrel (i.e. using tools to create a shape other than a sphere – for example a cylinder - is known as ‘marvering’), it could also be decorated with the addition of other glass applied to the surface of the bead.

Lamp winding (most modern lampwork beads are based on this method) is a more contemporary technique.

A cane of glass is heated in the flame of a small hand held /table mounted lamp. The glass is wound around a mandrel as before, but there is more control allowing for more ornate or complex decoration. Generally, this method was not used much before 1750 (at least by the Venetians). The beautiful contemporary black lampworked glass bead above was made by hand and flame by Studio Marcy.

Of beads produced today, furnace wound beads often originate from India. They are cheap to make, as they can be made from glass scraps, and they are relatively quick to produce. The grouping below are all Indian made lampwork or furnace glass beads - they are large in scale, ranging from 20mm to 40mm hole-to-hole length with hole diameters of 3-4mm. The beads have been shaped by hand tools rather then moulded.

The mandrel used for furnace wound beads is generally an iron rod, because iron loses its heat faster than the glass allowing the bead to be removed from the rod. The oxidised iron leaves a deposit of iron oxide on the inside of the bead hole. Lamp wound beads also exhibit a deposit, usually a white residue, within their hole, the result of the ‘release’ applied to the mandrel to allow the bead to be easily removed from the metal rod. The bead shown below is a Japanese Cherry Brand lampworked bead from post-war Japan. The basic wound glass lampworked core has been shaped with metal snips. The hole opening shows the remains of the white coloured release used.

Murano bead makers use copper mandrels that they remove from their beads by means of an acid bath – hence, one way you can determine whether a bead is genuinely of Venetian origin is to look for a clean hole, for this method of removing the mandrel from the bead leaves no trace on the bead.

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