In situ repair of delaminated float bath bottom refractory

A method of repairing a cavity in the bottom of a glass float forming chamber containing molten metal comprising:

• limiting the glass flow in the chamber to eliminate glass overlying said cavity, opening an access into the chamber above the level of the molten metal, inserting through said access and into the molten metal a repair block which comprises a material selected from the group consisting of tungsten, molybdenum, tantalum, and alloys and ceramic refractory combinations thereof such that the aggregate repair block has a higher specific gravity than the molten metal in the chamber, the repair block being of a size adapted to fit within the cavity without substantially projecting above the elevation of the chamber bottom, and moving the repair block into the cavity, whereby further growth of the cavity is inhibited.