摘要:
A method whereby slip is applied for providing an enamel coating to interior surfaces of a tank such as a heat exchanger of a hot water boiler, electric water heater and the like fabricated beforehand as by welding. In this method, a larger amount of slip than that actually required for applying the slip coating to the interior surfaces of the tank is introduced into the tank to be applied thereto with the tank being rotated, and the excess slip which has not been applied to the surfaces is forcedly drained from the tank at a rate higher than the rate at which the slip moves relative to the enameled surfaces and which moving rate is determined by the liquid level of the slip within the tank and the size of a discharge port, so that an enamel coating of a desired thickness can be formed on the interior surfaces of the tank. In order to forcedly drain the excess slip from the tank, pneumatic pressure is supplied to the interior of the tank prior to slip application. The particle size, specific gravity and drying means for the slip are disclosed herein.