Abstract: A method and apparatus for leveling a batch of pulverulent constituents in making a vitreous cellular material. A screen structure having at least one substantially flat screen layer is impressed down into and through at least a portion of the batch of pulverulent constituents. The screen structure is vibrated horizontally in a circular orbital motion while impressing the screen structure down into and through at least a portion of the batch of pulverulent constituents.

Abstract: A mortar composition for use in bonding cellular glass bodies includes a mixture, as expressed by percentage weight, of finely powdered reactive glass, such as cellular glass powder, in the range of between about 26 to 48 percent, inert aggregate filler in the range of between about 26 and 61 percent, and a silica sol binder in the range of between about 13 and 26 percent. The cellular glass powder has substantially the same composition as the cellular glass bodies being bonded. The inert aggregate filler preferably comprises round grained silica sand having a particle size wherein substantially all of the particles pass through a U.S. Standard #35 Screen and coarse cellular glass particles wherein substantially all the particles pass through a U.S. Standard #35 Screen. The ratio of finely powdered reactive glass to sol binder is maintained between about 1.8 to 1 and 2.0 to 1. By controlling the particle size of the finely ground cellular glass powder, the sol demand is substantially minimized.