Glass & Enamel
The origins and evolution of glassblowing
The art of glassblowing likely began in Syria during the first century BC. For many centuries, the core techniques remained largely unchanged, until mechanisation and the introduction of compressed air revolutionised the production of everyday items like bottles, jars and tumblers. Despite these developments, the creation of unique, decorative and high-quality glass remains a skilled craft. Many of the tools used by modern glassblowers would be familiar to their medieval counterparts: paddles for heat protection and shaping, marvers for rolling, jacks and shears for cutting and forming, the blowpipe for gathering and blowing the glass, and the punty rod for shaping the vessel's opening.
High-temperature equipment in glass workshops
A modern glassblowing workshop typically features three high-temperature zones. The melting furnace, where raw materials are converted into molten glass, reaches temperatures around 1150°C (2100°F). Once a gob of glass is gathered on the blowpipe, it begins to cool. To maintain workability, the glass is reheated in a glory hole-an insulated, refractory-lined chamber that keeps the material malleable while attached to the blowpipe or punty rod. Once the piece is completed, it is transferred to an annealing kiln or lehr, where it cools gradually to room temperature. This slow process prevents stress fractures or deformation and may take several hours depending on the thickness of the glass.
Glass composition and colouration
Glass is primarily composed of silicon dioxide. Additional metal oxides are introduced to modify its properties. Sodium dioxide increases viscosity and mechanical strength, while lead oxide enhances brilliance. Cobalt produces the deep blue associated with Bristol glass, chromium results in green hues, and both copper and silver contribute a range of colours. These oxides are also used in the production of enamel to create decorative effects. These oxides are also used in the production of enamel- a thin layer of glass fused to metal- to create decorative colour effects.
The development and applications of enamel
Enamelling- the fusion of coloured glass to metal- likely dates back to the earliest days of glassmaking, when it was used to create jewellery, cups, bowls and other finely crafted decorative objects. While historically enamelling began on precious metals like gold, silver and copper- especially for jewellery and artefacts- it later expanded to base metals such as cast iron, steel, aluminium, and even mild steel. It was not until the early 19th century that enamel was applied to iron cookware. The durable, easy to clean and attractive bright finish quickly gained popularity among manufacturers, advertisers and the emerging middle classes as enamelling spread to ranges, cookers, bathtubs and household appliances. While it may be a less popular finish in the modern kitchen, enamel remains essential in industrial contexts, from laboratory vessels and architectural signage to protective wall coatings in high-traffic environments.
In addition to glassblowing and enamelling, other hot glass techniques like glass slumping offer further creative possibilities. For tips on shaping artistic forms through kiln slumping, read our blog article on glass slumping.