PURPOSE: To obtain sound lining layer having thick upper coated glass with a little baking number of times, by thermally spraying and covering upper coating glass in semimolten state on under coated glass baked on base metal, at baking upper coated lass thereon.

CONSTITUTION: At first, under coating glass is thinly melted, stuck and covered on base metal by conventional technique such as wet spray grazing method. Next thoroughly dried upper glass powder is rapidly plasma sprayed on the under coated glass cover surface. Type for supplying spraying powder to plasma jet from outer part is used, etc. for plasma spraying gun used to spraying, and upper coating glass powder is thermally sprayed as semimolten state. In this case, since sprayed surface is made uneven, after end of the spraying, it is after heat treated at operating temp. of upper glass coating execution in baking furnace to melt and soften melted and stuck upper coated glass. Thereat, since glass thickness is reduced by about half, this is precalculated and thermal spraying is continuously carried out until a prescribed thickness is attained.