The back flat arch of the chauffer in the float glass furnace often suffered from alkali erosion and local temperature changes in furnace, and the whole ring of bricks on the flat arch fell off and flank on the sides of the chauffer under the back flat arch of the chauffer collapsed completely, forming a defect about 500 mm wide and 2,000 mm long, moreover, flame penetrated from the furnace seriously. Further erosion can cause collapse of the back flat arch of the chauffer and threaten the safety of the furnace structure. With the high temperature ceramic soldering technology combining with the high temperature induction ceramic welding gun of the company, the defect was successfully repaired and the service life of the furnace was prolonged for another two years.