Abstract: Coating a ceramic substrate on a second major surface while avoiding damage to a coating comprising a matured enamel frit previously applied to the first major surface. After coating one major surface with an enamel frit composition and maturing its frit component thereon, the substrate is oriented with its matured enamel frit coating facing downward and coated on its second major surface with one or more frit compositions that must be heated to an elevated temperature at which the previously matured frit coating would be prone to damage on contacting a solid member. This invention avoids such damage by supporting said matured frit on a gas bed in spaced relation to any solid member capable of demaging the enamel frit component during the portion of the heating and cooling cycle needed to mature the frit coating on the second major surface when the temperature of the substrate is elevated to a minimum temperature approaching that at which the previously matured frit would be prone to such damage.