1. Description
    2. Applications and Qualities
    3. Range of Float Glass Products

    Download: Float Glass Product Sheet
                    Technical Characteristics
                    Risk of Thermal Stress

• Mixing of raw materials: silica sand (basic ingredient), sodium carbonate (melting agent), calcium carbonate and dolomite (stabilizing elements), cullet (recycled glass) and if necessary metallic oxides (as dye for body tinted float glass)
• Melting at about 1500°C
• Glass flows out of the tank at about 1050°C and 'floats' on a liquid tin bath in the float chamber. The temperature is gradually reduced to 650°C. Under gravity, both surfaces become flat and parallel.
• Annealing: the glass has now sufficiently solidified to be transported on rollers. On the annealing line, the glass temperature is further reduced from 650°C down to about 200°C.
• Final stage: the glass ribbon is trimmed on the sides to a standard width (e.g. 321 cm) and cut to glass sheets of a desired length. The glass sheets are inspected.

When flowing out of the glass tank on the tin, the glass naturally takes a thickness of about 3- 4 mm. This thickness can be increased or decreased by changing the conveyor speed and the use of siderollers.

There are significant differences in glass quality between different float manufacturers. These quality differences can amongst others be attributed to:

• Quality and purity of the raw material
• Technology, condition of the furnace and available operational skills
• Control of the annealing process: glass tension, surface properties, variations in thickness,…
• Quality control procedures.