Shaping glass sheets by gravity sag bending followed by blow forming

A method of shaping at least two glass sheets to a complicated shape comprising:

• (a) preliminarily shaping said glass sheets to a preliminary shape about a single axis of bending by
• (1) supporting said at least two glass sheets over an upward facing shaping surface of an outline shaping mold,
• (2) heating said glass sheets to the glass deformation temperature until said sheets sag to form an assembly having a prebent shape conforming to said upward facing shaping surface,
• (3) cradling said assembly of prebent glass sheets in a thin flexible blanket of fiber glass cloth with the peripheral edge of the blanket wrapped over the edge of said assembly,
• (4) applying a frame-like ring to the portion of said blanket wrapped over the edge of said assembly to hold said blanket taut against said assembly and reversely folding said fiber glass cloth blanket around said ring to form a ring assembly,
• (5) positioning the ring assembly so formed over a shaping surface of compound shape of a blow forming tool,
• (6) heating the ring assembly so formed to the glass deformation temperature while mounted over said shaping surface,
• (7) enclosing said blow forming tool to form a sealed chamber containing said ring assembly, and
• (8) pressurizing said sealed chamber at a low positive pressure while maintaining said deformation temperature until said glass sheets conform to said shaping surface of said blow forming tool.