How Crystal Glass Is Made
Glass has been made for thousands of years and it was the ancients that began using crystals in their natural state for dishes, beads and sculpture. Early producers of crystal started to add metals to glass to change its appearance, and they found that lead made the most difference. It makes many enhancements, strength, durability and has the quality to produce a ringing sound, and perhaps the most attractive benefit is that it creates a shimmering, silvery appearance that can be enhanced even more by cutting.
History of Crystal
The most famous producers of crystal glass in Europe were the Venetians, French, Bohemians, English and Dutch. Although crystal glass was being made in Egypt and Roman times well before the European explosion. George Ravenscroft was a leading light of English manufacture in the mid 1600’s, and patented a process of making flint glass. And trying to escape tough tax duties in England many of Ravenscroft’s English colleagues moved their factories to Waterford in Ireland in the late 17th century. Other notable producers at the time were, Offefors in Sweden, Baccarat in France and Swarovski in Austria.
The Raw Materials for Glass
The basic materials for producing glass are a mix of silica-sand, potash, and red lead. There was a yellow oxide of lead that was used in the very beginning of lead crystal production, made out of red-lead oxide. Silica is produced naturally from sand obtained from beaches and in its pure form produces fantastic hexagonal crystals. Every factory concocts its own mixture, which defines the type of crystal it produces.
How to Make Crystal Glass
The manufacture of glass goes back two thousand years, but little has changed in the materials used although design has changed greatly.
- Firstly, the crystal mixture is molten in a furnace at 1,200 degrees centigrade, then the red-lead oxide is added. Depending on how this is added will directly affect the purity of the finished product. It is key to control the temperature during this process as discoloration can take place at this stage.
- It can take up to six artists to then blow the glass who all work in harmony as a team. Blocks and moulds made out of wood are used to make a basic shape. As soon as the hot glass touches the mould it starts to cool, so the artisans have seconds to produce their work.
- The glass blowers have a high level of skill, they combine breath control with physical strength to create their designs. The thickness is of ultimate importance, to suit the type of object it will become and to help the cutting
- To slow down the hardening process the blown glass is placed in an annealing oven, this stops the crystal cooling too quick and stressing the glass too much.
- The cooled glass is now in the hands of the craftsman cutter, who draws on the object first, then follows his lines with a power driven cutting wheel. After this has been done the object is polished, and this takes immense skill as one mistake can ruin the piece.
- Finally, the finished product is dipped into acid which removes any layers of dirt gathered in the engraving or on the surface.
Making crystal glass is a highly skilful operation, at any of the stages disaster can occur and the piece is worthless. There is no doubt that crystal glass is worth every penny that it costs to produce.