present invention an open type glass lined tank capacity of about 100 liters jis r4201 was fabricated and about 100 cm 2 of its glass layer on the inner wall was removed by grinding to simulate an extended damage area the damaged area then was repaired and tested in the same manner as described in example 15 according to the present invention the resulting repair exhibited no sign of cracking in the existing glass layer around the repaired area application of repair layer to a region of irregular configuration in container structure the same repair and test of example 19 was effected on the curved area of a flange 6mm in curvature radius of the tank fabricated in example 19 again no cracking was detected in the existing glass layer around the repaired area the adhesiveness of the repaired layer to the steel substrate then was tested in the same manner as example 18 and as a result no cracking was detected a repair agent is prepared by mixing and stirring at 25 u00b0 c for one hour a sol gel solution containing the ingredients listed in table 3 table 3______________________________________silicon tetraethoxide 20 g85 phosphoric acid 1 gethanol 20 gwater 1 g______________________________________ separately from the ingredients of table 3 there are provided different types of inorganic ultrafine powders having a particle size less than about 1 u03bcm in diameter including silicon carbide ultrafine powder particle diameter lt 1 u03bcm silica ultrafine powder particle diameter dozens of angstroms prepared by a gas phase process.