A method of forming a garage door panel comprising:
- a. forming a flat rectangular section of metal having a top longitudinal side, a bottom longitudinal side, a first transverse end and a second transverse end, a front surface and a rear surface into a pre-formed garage door metal section by creating at least one decorative portion on the front surface, bending the top longitudinal side into a top portion with a male retaining member extending from the first transverse end to the second transverse end, and bending the bottom longitudinal side including a bottom portion with a female receiving member extending from the first transverse end to the second transverse end;
- b. placing the pre-formed metal section front surface down onto a conveyor apparatus with the conveyor apparatus moving the pre-formed metal section in a longitudinal direction from the second transverse end to the first transverse end, a pair of fixed spray nozzles above the rear surface separately respectively spraying liquid isocyanate and liquid polyol resin to form two-component mixture onto said rear surface of said pre-formed metal section and spread across the rear surface from top section to bottom section, the two-component mixture of liquid isocyanate and liquid polyol resin spread onto said rear surface of said pre-formed metal section hardens into a polyurethane foam section in less than ninety (90) seconds;
- c. forming a combination insert including a polystyrene section having a front surface and a rear surface and separately forming a twin wall polypropylene section having a front surface and a rear surface, the front surface of the twin wall polypropylene section adhered to the rear surface of the polystyrene section;
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- d. during this ninety (90) seconds while the liquid isocyanate and liquid polyol resin mix to create the polyurethane foam section, placing the combination insert with the front surface of the polystyrene section placed onto the liquid isocyanate and polyol glycol with the combination insert retained by the polyvinyl foam and the combination insert slid into and under a longitudinal top interior edge and the interior of top section up to but not past a beginning of male engaging member and a longitudinal interior bottom edge is pressed away from its location spaced apart from the rear surface of the metal section and the combination insert is slid under said longitudinal interior bottom edge and under the bottom section but not as far as female receiving member, the twin wall polypropylene surface being a rear exterior surface of the garage door panel.