How Glass Windows Are Made

While gazing out of a perfectly smooth, clear glass window, have you ever wondered how it was created? Many people don't realize that the beautiful windows they use every day in their homes, cars and office buildings went through an incredible process to reach the size and shape they are in now.

Let's start with the process of creating glass, and then move to how that glass becomes the windows you see every day.

How Glass Is Made

Glass windows are manufactured in a factory, undergoing an intense process where temperatures reach up to 1500 degrees Celsius. Here's what happens:

• Glass-making materials are combined. This includes sand, soda ash, dolomite, limestone and salt cake.
• These materials are mixed together with surplus glass and heated in a furnace to 1500 degrees Celsius. Furnaces can hold more than 1200 tons of glass.
• The glass melts, and will then be brought to a temperature of 1200 degrees Celsius.
• The glass is fed into a bath of molten tin. Tin is ideal for the glass-making procedure because it mixes perfectly with the glass.
• The glass floats onto the tin surface, transforming into a sheet. The temperature is reduced, and the sheet is lifted onto rollers. The differences in flow speed and roller speed create glass sheets of different thicknesses and widths.
• The glass is cooled and reheated slowly to increase strength and prevent shattering. Or it is tempered, meaning it is reheated and chilled with sudden blasts of cold air.
• The glass may be glazed and coated with insulated window glazes, heat absorbing tints, or other coatings.

How Windows Are Made

Now that the glass has been created, how does it become the window in your home? Here's what happens at a window-manufacturing plant:

• Dimensions are entered to fit a particular window. The glass is cut by machines to fit the desired size.
• The glass is cleaned with a high-pressure cleaner.
• Panes of glass are sealed together.
• Pieces of frame are cut and welded together.
• The frame and glass are assembled.

As you can see, the process of making windows is complex and requires intricate machinery and experienced technicians.