A method of forming a hollow article includes injecting a first molding material into a first mold cavity at a first injection pressure to form a first molded shell and injecting a second molding material into a second mold cavity at a second injection pressure to form a second molded shell. The first molded shell has a first peripheral edge, and the second molded shell has a second peripheral edge. The method includes positioning the first shell and second shell into facing relation with the first and second peripheral edges in a third cavity, and injecting a third molding material into the third cavity at a third injection pressure to bond together the first and second shells along the first and second peripheral edges to form the hollow article. The third injection pressure is less than the first injection pressure by at least about 3.5 bar.