Plywood manufacture using foamed glues

Plywood is made by continuously propelling a liquid plywood glue in unfoamed condition at a predetermined flow rate, continuously foaming the glue as it is propelled, and continuously extruding or otherwise applying the foamed glue to the surface of a plurality of wood veneers. The flow rate of the unfoamed and foamed glue is maintained substantially the same on a unit weight of liquid glue per unit time basis. The veneers then are laid up into a plywood assembly and pressed, whereupon the pressure breaks the foam and unites the veneers. The method is applicable generally to the production of laminar products by the application of a foamed liquid to a solid surface.