A method of forming a polyurethane article wherein first and second components of a polyurethane system are sprayed into an unconfined space above a mold. The first and second components are sprayed together to mix initially in the space above the mold and then are deposited in the mold on an in-mold coating that was previously applied to the mold. The two components of the polyurethane system and in-mold coating are subsequently removed from the mold as a flexible polyurethane skin. The skin may then be placed in a second mold along with a reinforcement. Structural polyurethane foam may then be injected to the second mold where it bonds to the reinforcement and the skin to form a finished polyurethane article having a flexible skin adhered to its surface. A post-mix spray nozzle assembly is provided with a central nozzle forming a first hollow conical spray pattern and a coaxially aligned annular nozzle forming a second hollow conical spray pattern. The first and second hollow conical spray patterns intersect in space remote from the nozzle and form a hollow circular spray pattern.