What exactly is lampwork?
Lampworking (also known as flameworking) is the art of melting glass in a flame to produce beads or sculptural pieces. Although the name originates from the oil lamps originally used as the heat source, modern lampworkers generally use a gas-fuelled torch. I’m currently working on a Nortel Minor torch that uses a mixture of propane and oxygen to produce a flame hot enough to melt the glass.
What sort of glass can you use?
Lampworkers can use a variety of different types of glass, but I mainly use soft (or soda-lime) glass produced in Italy, Germany or China. I buy the glass in rod form (4-5mm diameter and about 30cm long) and in a wide variety of different colours, both transparent and opaque. One of the joys (and sometimes frustrations) of lampworking is the way the chemicals used to colour the glass can react with each other in the flame, creating effects that are sometimes quite unexpected!
But how do you get a hole in it?
Beads are made on mandrels (thin steel rods) that have been dipped in a liquid clay-like mixture, called bead release, so that the molten glass doesn’t stick permanently to the steel. Mandrel and glass rod are both heated in the flame and then the molten glass is wound onto the mandrel to build up the body of the bead. The bead can then be shaped using a combination of heat, gravity and hand tools or formed in a brass press. Decoration can be applied to the surface of the bead using stringer (very thin glass lengths), frit (crushed glass pieces), enamel powder or silver foil or wire – the possibilities are almost endless!
The process of making the bead may have introduced internal stresses into the glass that could cause the bead to crack. This is because glass is a very poor conductor of heat and cools unevenly, unless cooled very slowly. To eliminate any stresses and prevent future cracking, finished beads should be annealed (soaked in a kiln at a specific temperature for a period of time) and then cooled gradually at a constant rate.
And finally …
The annealed bead is then removed from the mandrel and the hole thoroughly cleaned to remove the bead release. Voilà, one lampwork bead!