Expansion joint left during brick-laying of the horse-shoe flame glass furnace was oversized and failed to join the silicon bricks tightly after furnace heating up, causing fire inside the furnace hearth penetrating into the small pool, and burnt the low-melting materials in the fire- block wall, which fell into glass metal and formed a number of black “bumps” on the surface of glass plates and seriously affected the quality of glass. Using the ceramic welding technology of the company, the expansion seams on block fire wall were welded tightly and the problem was solved.