Method for the manufacture of porcelain coated metal boards having interconnections between the top and bottom surfaces

Claim 1

An improved method for the manufacture of porcelain coated metal boards of the type having a connector extending through the board from the face to the reverse surface thereof, said method comprising the steps of: (a) providing a metal core for said board; (b) forming an aperture through said core at the position wherein said connector is to be provided, said aperture being formed in a predetermined size and of a configuration which is larger than that of said connector; (c) positioning said connector within said aperture in a spaced apart relationship from the edges of the aperture with the terminal ends of the connector extending beyond the opposite surfaces of the metal core a distance sufficient to at least extend to the face and reverse surfaces of the hereafter to be applied porcelain coating; (d) inserting a fusible glass frit into the space between the connector and the edge of the aperture, said predetermined size and configuration of the aperture being such that adequate space is provided for the insertion of a sealing effective amount of a fusible glass frit into said space; (e) heating the assembly of the metal core, connector and fusible glass frit to at least the sintering point whereby the glass frit fuses and seals said connector in the spaced relationship to the metal core; (f) applying a uniform thickness coating of porcelain frit to the face and reverse surfaces of the metal core and thereafter firing said porcelain; whereby a porcelain coated metal board is obtained having substantially flat surfaces and having a connector extending between the face and reverse surfaces thereof.