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History of Glass Making

It is uncertain when glass making first began. However, the Bible does mention the rarity of glass by comparing glass to gold. Glass was used to make fake gemstones as jewelry pieces. The glass gemstones would be dyed a color that could not be found in the natural world. At times, prices of these glass gemstones were more expensive than real gemstones due to the complex process required to create them.

When glass making became a popular art form, other everyday objects were produced as out of glass such as bowls, vases, and cups. Glass blowing started in the Mediterranean and later became very popular in Venice, Italy. Venice soon became the glass capital of world. The island of Murano (about 2 miles away from Venice) is home to many glass masters. At certain workshops today, visitors are welcome to observe glass artists at work!

How Glass is Made

Have you ever seen the movie Sweet Home Alabama starring Reese Witherspoon and Josh Lucas? If you have, I am sure you have been wondering if it is truly possible to transform sand into beautiful glass vases by posting metal rods during a lightening storm.

Research has shown that when lightening strikes, there are instances when sand dunes create fulgurites. Fulgurites are natural hallow tubes of glass; with the right temperature, heat will form silica glass in the path of where the lightening hit. However, only on special occasions is the glass large enough to be molded into something like a vase. Natural glass is not necessarily as high quality as portrayed in the movie.

Aside from this natural phenomenon- glass manufacturers have another way to create high quality glass. Raw materials (silica, soda, and lime) are combined at the right temperature (at least 2,000 Celsius / 18,030 Fahrenheit). Soda (sodium carbonate) is a term for raw sand; this additional material helps lower the melting point. To prevent the glass from weathering, about 10 percent lime (limestone) is contributed. The mixing process lasts for about 24 hours.

Shaping Glass

There are several methods to shape glass: blow, press, drawn, and cast.

Blow

This method requires a blob of molten glass to be placed at the end of a hollow iron blowpipe. Air is blown through the pipe to form a pear-shaped bulb out of the molten glass at the other end. The glass bulb is rolled on an oiled slab and shaped as desired by the glass blower. Other tools are sometimes used to help shape the glass. To keep the new glass vase from rapidly cooling, it is placed in the an oven to be reheated from time to time until it is complete.

Press

With this method large quantities of molten glass are made in a large furnace and separated into smaller portions of molten glass for production. Each piece of molten glass is placed into moulds and pressed, resulting in a completed glass product which is left to cool.

Drawn

This method is used to manufacture rod or tube-shaped glass. Molten glass is drawn over a hollow cylinder or cone that has air blown through to prevent the glass from collapsing inward.

Cast

Molten glass or glass chips are placed into molds and then heated. Modern day moulds are made of wood or plaster.

Famous glass artists, such as Dale Chihuly a world famous glass blower, often display their works of glass art at exhibits world wide. Check for glass exhibits near you to see these magnificent works of art in person!