surfaces of thermally conductive substrates are covered with thermoplastic polymers , particularly certain fluorocarbon polymers by bonding said polymeric materials directly to surfaces of said substrates . adhesives , etchants , or the like are not used as bonding elements . the process involves treating the surfaces to make them wettable by water and then cleaning the surfaces , if necessary , followed by heating the substrate to a temperature at which the polymer melts , gels or softens , then placing the polymeric material into contact with the prepared surfaces and applying pressure on the polymeric material to force it into fusing and bonding contact with the heated surface and then cooling the substrate to a temperature below the softening point of the polymer . the products produced are preferably rolls . in their covered form as produced by this invention they are useful as processing rolls in office copier &# 39 ; s fusing systems , rolls used in food cooking processes , and the like .