Steam bonding of solid lignocellulosic material

In a method of bonding solid materials and thereby producing a waterproof bond, comprising providing on a surface of said solid material an adhesive-free bonding material comprising at least one sugar, starch or mixture thereof, and pressing surfaces of said solid material together at an elevated temperature and for a time sufficient to effect bonding by transformation reactions of the sugar, starch or mixture thereof, and wherein the time, temperature and pressure are sufficient to produce a waterproof bond, the improvement wherein:

• said solid material is a lignocellulosic material, and during said pressing said lignocellulosic material is maintained in a sealed press and subjected to live steam to heat the interior of the solid material to about 320.degree.-420.degree. F., said live steam serving to generate natural catalysts and to activate phenolic material on surfaces of said lignocellulosic material, which phenolic material reacts under the effects of said steam with said sugar, starch or mixture thereof to produce said waterproof bond.