Piano hinges are strong and availiable in many shapes and sizes. Also a variety of materials, in your case they can be had in aluminum or SS. I bought a 48" long heavy duty SS piano hinge for my side x side...not cheap at 54 bucks but very heavy duty and rust free. You would probably be fine with an aluminum one. Lots of different fasteners out there, when you get the design figured out, do your fastener research, lots to choose from !!! Also remember that piano hinges can be cut to whatever length is needed, no need to figure an exact length. Lots of good ideas posted here, let us know what your finnished project looks like !!