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What is Float Glass

Float Glass

Float glass is a type of glass that is made by pouring molten glass onto a bed of molten tin. This process ensures the glass spreads out evenly, reducing the likelihood of air bubbles or defects. Float glass is predominantly used in windows and windshields due to its clear, distortion-free surface. Its invention marked a significant advancement in the glass industry, allowing for the production of larger, more flawless sheets of glass, which later became the foundation for many specialized glass types. After the float glass process, these sheets can undergo further treatments to become laminated, toughened, or other types of glass.

History of Float Glass

The float glass process was invented in the 1950s by British engineer Sir Alastair Pilkington. Pilkington was looking for a way to produce large sheets of glass without the defects that were common at the time. He discovered that by floating molten glass on top of molten tin, he could create a smooth, consistent surface. This invention revolutionized the glass industry, making it possible to produce large, flawless sheets of glass that were ideal for a wide range of applications.

How is Float Glass Made

The production of float glass starts with melting standard soda-lime-silica glass ingredients in a furnace at around 1500 degrees Celsius. When the molten glass reaches the desired temperature, it’s poured onto a pool of molten tin. The tin serves as a leveling agent, ensuring the glass spreads evenly. As the glass cools, it solidifies and, once at room temperature, is cut into desired sizes.

This method yields large sheets of glass with minimal imperfections, ideal for clear applications like windows and windshields. However, it’s essential to note the environmental implications of float glass production, especially concerning energy consumption. Technological advancements are now leading to more energy-efficient production methods.

Applications of Float Glass

Float glass’s clarity, strength, and durability make it suitable for various applications. It’s the foundational medium for other glass types like laminated and toughened glass, commonly used in windows, windshields, skylights, and shower doors. Additionally, its adaptability makes it a favorite for furniture, shelves, and tabletops. With urbanization and the increasing use of glass in modern architecture, especially in developing countries, the demand for float glass in construction and interior design is on the rise.

Advantages of Float Glass

  • High clarity: Float glass has very few imperfections, allowing light to pass through it more easily, resulting in higher transparency.
  • Easily cut and modified: Float glass can be easily cut and modified to fit a variety of applications.
  • Easy to clean: Float glass has a smooth surface that is easy to clean and maintain.
  • Low cost: Float glass is cheaper than toughened and laminated glass.

Disadvantages of Float Glass

  • Safety concerns: Float glass is not an approved safety glass, meaning that it is not shatter-resistant and should not be used in applications where safety is a concern.
  • Prone to scratches: The smooth surface of float glass can scratch easily, so it is not ideal for applications where the glass will come into contact with other surfaces.

Float Glass FAQ

Float glass doesn’t meet AS1288 standards for safety glass, meaning it’s not shatter resistant. Toughened glass is float glass that has been treated to be stronger and more resistant to breakage.

While float glass is not an approved safety glass, it can be used in a variety of applications where safety is not a concern such as windows or doors which cannot be mistaken as an opening, shelves, and furniture.

Yes, float glass can be recycled. The recycling process involves crushing the glass into a fine powder and then using it to create new float glass sheets.

Float glass is available in a variety of thicknesses, from 2mm to 19mm. The most common thicknesses used in applications such as windows are 4mm, and 6mm.

Picture of Khalil Chahine
Khalil Chahine

Khalil is the owner of Splendid Window Glass Repairs and has over 8 years experience as a glazier specialising in window glass repair, replacement and installations. Khalil takes great pride in his work and prides himself on providing an excellent service to all of his customers, no matter how big or small the job may be.