Glass blowing has two main techniques free blowing and mold blowing. Both begin with raw glass materials heated to approximately 2,400 degrees Fahrenheit. The exact mix of raw materials used in glass making varies based on the type of glass being produced;the composition is typically a mixture of fine white sand,silica, limestone, soda ash and other chemicals to color the glass. The differentiation between the two glass blowing techniques occurs after the raw material is heated.
Free blowing is the oldest glass blowing technique, dating back to the first century BC and changing very little since. In free blowing, the molten raw glass making materials are placed on the tip of a hollow metal blowpipe. The craftsman blows small puffs of air into the pipe and turns the pipe according to the effects he wants to achieve. This method gives the artist the greatest amount of artistic control.
Mold blowing begins when the molten material is placed into a metal or wooden mold and then blown to expand to fit the mold. This type of glass blowing is the most common way to create functional everyday glass pieces. It is also the preferred way to achieve uniformity in design and detail.