Abstract: Platelet assemblies are formed from bondable platelets, such as diffusion-bondable, brazable, or adhesive-bondable platelets, with void regions in the platelets to form channels or open spaces in the finished platelet assembly. To improve the response of the platelet assembly to pressure bonding as well as to post-bonding fabrication processes such as forming, machining and welding, the void regions are filled with a sacrificial material which transmits the load of the applied pressure in the same manner as the remainder of the platelet, and yet which is removable from the finished platelet assembly by either thermal or chemical liquefaction after all potentially damaging fabrication procedures have been performed on the platelet assembly.

Abstract: A bituminous roof covering material, particularly suitable for use as first layer in a multilayer roof covering system which is applied while adding heat. The material comprises a carrier provided on both sides with a bituminous layer and with a layer formed by a perforated metal foil. According to the invention, the carrier and the bituminous layers applied thereto on both sides are closed layers without perforations, and the bituminous layer interposed between the perforated layer and the carrier consists of adhesion-active bituminous material.