It is no secret that glassblowing is an art that has been in existence for thousands of years. Many people will agree that it takes a special type of talent to be able to successfully make anything. But what many people do not know is how glass blowing actually works.
There are two major methods of glass blowing. These two methods are called free blowing and mold blowing. Free blowing is still commonly used, especially for those who practice glassblowing for artistic purposes. Mold blowing is the method that is most commonly used due to its ability to be used for mass production.
Free blowing has been in common use since about the 1st century B.C. and was the predominant method that was used by glass blowers up until current times. It is fairly easy to understand how this method is done even it is not quite so simple to do. The glass blower uses a blowpipe in this method. The glass blower will blow short puffs of air into the blowpipe which will enter the molten part of the glass at the other end that is called the gather. From there they will inflate the glass and work it into the desired shape. This is done by rotating the blowpipe, swinging the blowpipe and controlling the temperature of the glass while they are blowing the glass. This method produces many different things from vases to cups and even window glass.
The mold blowing method is newer than the free method of glass blowing by a few hundred years or so. The difference between this method and the free blowing method is the use of either wooden or metal molds. The glass blower blows through the blowpipe while the molten glass is laid in the mold. There are two types of molds which are the single-piece mold and the multi-piece mold. The different molds give the final shape to the glass and will allow the glass to be shaped into nearly anything that can be imagined by the glass blower. This particular method is thought to take less skill than the free blowing method because the final design is not dependent upon what the glass blower can produce but largely upon what the mold looks like.
While the two methods do have several differences in the final production of the glass piece, there are some similarities. For example, the glass that is being worked with has a temperature that is in the range of 1600 and 1900 degrees. There are also three furnaces that are used throughout the glassblowing process. The first is just called the furnace and is what holds the molten glass. The next furnace is called the glory hole. This furnace is used to reheat the glass as needed while it is being worked on. The next and final furnace is called the lehr or the annealer. This one is extremely important and is used to slowly cool the glass over a period of hours or days depending on what the piece is. This furnace is so important because if the glass is not slowly cooled, it can develop cracks or even completely shatter.
The process of glassblowing is extremely complicated and takes quite a bit of skill. This skill is something that would take years to fully learn and is something that can be continually refined. This particular skill has not changed drastically since it was developed and it appears that the current method of glass blowing is the method that will be handed down to the following generations of glass blowers.