A process is provided for making stiff, lightweight laminate materials. At least one sheet of textured lamina having raised pointed structures is forced against a softer plain lamina so as to embed the structures therein. The pointed structures raised from grooves carved into the surface of the sheet material by means of a set of teeth carried on a knife element. The pointed structures may pierce through the softer lamina such that the protruding tips may be bent over or clinched to prevent their easy withdrawal. Two such texturized lamina may be used to sandwich and pierce through the softer lamina and are co-clinched by the other. In this way a light and stiff laminate is created.