Glass’ molecular structure is between solid and liquid. Some people say it’s a super cooled liquid but a lot of people don’t agree with this terminology since it’s only partially correct. The methods for creating glassware have never changed much. In every factory they make glasses following the same ancient ways using big ovens and hallow blowing metal tubes.
The main ingredient in making glass is silica sand. When you heat it along with other chemicals it turns into a syrupy liquid that you can then mold or blow into a particular shape. Add lead oxide and you have lead crystal. This is much softer than regular glass, making it easier to cut with intricate designs.
To begin the process of making glasses a craftsman starts with silica sand, which is a very pure type of sand. Then they add nickel oxide to help the silica sand melt, lead oxide, potassium carbonate, potassium nitrate and antimony to give the finished crystal its smoothness, heft and sparkle. They then compress the mix into pallets. They heat the pallets for 18 hours creating a mass of molten glass they call “the melt”. To that they add cullet, a term for excess or rejected crystal. The cullet smoothes out the melt. A blower now uses a hollow blowing iron made of tempered stainless steel to collect some of the melt. He constantly rotates the iron so the melt clings together in what is called “a gather”. The blower rolls the gather on a heat resistant table. This sparks a flame because the table is coated with bees wax to prevent the molten crystal from sticking.
The blower exhales a slow steady breath of air to create the base of the piece called “the ball”. After letting it cool for 90 seconds he dips the ball back into the furnace to coat it with another layer of molten crystal. This fortifies the ball. Now he begins shaping the ball using various wooden tools. Tools like “the divider” are used to create grooves so the ball will fit into a mold. He now inserts the ball into a steel mold. Our company has hundreds of these molds for their glassware. The craftsman coated the inside of the mold before hand with a paste of linseed oil and charcoal dust. This prevents the ball from sticking which would cause flaws in the crystal. The blower releases the ball now called “the bowl” using a foot pedal.
After cooling the bowl for one minute, another craftsman called the stemmer adds another gather to create the stem of the glass. He clips the gather with heat resistant scissors. He uses a wooden divider to shape the stem area and a metal divider to stretch the gather into the shape of the stem. The stemmer must be highly skilled. There is no mold or pattern to follow. He relies entirely on eye sight and more than that, on experience, intuition and patience. He cools the stem with layers of wet newspaper. They absorb heat well and don’t leave marks or flaws. Next, another craftsman adds more gather to create the foot of the glass. He uses a wooden tool called “the pitch” to flatten the foot. He also shapes the foot by hand with wet newspaper. Using a metal template insures the craftsman that the foot of the glass has the right dimensions. Everything is handmade so each piece may differ slightly. The piece then goes into an oven at 450 degrees Celsius. At the end of the day they switch off the oven to let the glasses gradually cool over night to room temperature. This process is vital and creates a better quality of glasses. If cooled rapidly the glasses may deform slightly or change the chemical composition by just a bit. But this is enough to not make a perfect glass.
The next day a craftsman uses a settling torch to cut the glass and remove the cap. They use an old record turn table to spin the glass around and make the cut. For precision, they smooth and bevel the rim with a diamond coated steel grinder. Another craftsman called “the cutter” marks out a grid with a water proof pen. He uses another type of turn table to steady his hand as he draws. It’s not an exact pattern, just a general guideline to create the design of the piece. The glass is then moved to a grinder where a design is cut following the pattern of the craftsman’s markings. Water cools, lubricates and cleans the area during the artistic cutting of the pattern. There are two types of cutting: wedge and flat. Wedge cutting creates the deep, intricate cuts. Flat cutting creates smoother, less angled cuts. If he uses a wedge method, this can only be done with diamond tipped wheels. Finally the cutter moves to the foot of the glass and crates artistic cuts which may span for the entire foot of the glass. As a final step an inspector does a detailed, quality check before etching the company logo.
Various other glassware products have similar production processes. Depending on the complexity of that specific glassware our company may use machines to complete several stages. For simple pieces this adds precision, it decreases its purchasing price by a significant amount and it allows delivering the order in a shorter period of time.