The edge quality of float glass plays an important role in the manufacture of automotive windshields as well as in tempering of sidelites and backlites. It is controlled by scoring tool, rate of scoring, type and amount of coolant used and handling of the edge. An effective method for quantifying the edge quality is to measure its strength in 4-point bending using a specially designed fixture that stresses the entire surface of the edge. This paper presents edge strength data for 4mm thick float glass as a function of different coolants including water. A sample size of 10 specimens was used to obtain statistically significant data to help study the effects of different coolants. All of the fracture ofrigins were found on the edges and were analysed for mirror/mist boundary.
