What is float glass and how is it made?

Float glass is a type of flat glass produced through a process where molten glass is floated on a bath of molten metal (typically tin) to produce a uniform and consistent thickness, flatness and surface quality. This process results in high optical clarity, making it suitable for a wide range of applications, including windows, mirrors, picture frames, tabletops, and shower enclosures. Its versatility and durability make it a popular choice for many industries and applications.

The Float Glass Process

The principal ingredients in soda-lime-silica float glass include sand, soda ash, dolomite, and limestone. The quality of the produced glass depends on the purity and grain size of the input material. The float glass production process begins with the raw materials being melted in a furnace at approximately 2,900°F or 1,600°C. The continuous strip of glass exiting the furnace is known as the “ribbon”.

Forming takes place on a tin bath. The liquid glass floats upon the tin bath at approximately 2,000°F or 1,100°C, to achieve a flat, smooth surface without polishing. On exiting the tin bath, the glass is progressively cooled in the annealing lehr, which releases stress from the glass ribbon. A uniform stress profile supports the reliability of subsequent glass cutting operations. Laser sensors or high-resolution cameras installed along the line capture production data which is evaluated by yield-optimization software to direct a robotic cutting system. The ribbon is cut into stock sheets which are then prepared for storage. The sheets are sprayed with a separation material which helps to prevent scratches and sticking as the lites are arranged into packs.

Glass is produced in standard metric thicknesses of 2, 3, 4, 5, 6, 8, 10, 12, 15, 19 and 25 mm, with 10mm being the most popular sizing in the architectural industry. Molten glass floating on tin in a nitrogen/hydrogen atmosphere will spread out to a thickness of about 6 mm and stop due to surface tension. Thinner glass is made by stretching the glass while it floats on the tin and cools. Similarly, thicker glass is pushed back and not permitted to expand as it cools on the tin.

Clear float glass is the basis for every magnificent glazing project. It can be processed in every imaginable way, and is often used as a base glass for an entire range of glass products including coatings, mirrors, back painted glass, acid etched glass etc.

Color options

Standard float glass, normally called clear float glass, has a slightly greenish appearance that is particularly visible when looking at the edges of the glass. This slightly greenish tint is due to the presence of iron in the raw materials used to produce float glass. The iron content can be reduced to produce a more neutral glass, known as “low-iron glass”, which can be a good choice for interior design, but also for architects who wish to create very crisp and clean glazed façades.

If a tint to the glass is desired, metal oxides can also be added to the raw materials to provide a grey or green tint. It will not only affect the appearance of the glass but also its visible light and solar heat transmission.

Tinted glass can be combined with low-E coatings to allow more aesthetic options of substrate/coating combinations, to further improve the solar performance of the glass, as well as selecting the right level of light transmission and transparency to help mitigate glare and maintain some privacy.

The diffuse glass and AR-coated diffuse glass produced by Yuhua have cooperated with many large commercial greenhouses in agriculture, horticulture, nurseries and experiments. We have cooperated with large greenhouse project companies such as Havecon, Van Der Hoeven, Kubo, etc. for many years. Yuhua greenhouse glass has a light transmittance of up to 99%, and haze 5/10/20/30/50/70/75 greenhouse diffuse glass is available!

Need more detailed information or a solution of greenhouse glass? Need guidance on how to choose the right glass for your greenhouse?

Consult online customer service, leave us a message or send us an email!