Even though the ribs are connected by a wire through their ends, they only conduct intermittently. Solder a wire to the center shaft and then to the rest of the ribs. Steel solders easily if you wire brush it first and then add some flux. The aluminum sheet is held onto the wood with hot glue. However the glue doesn't stick well because the aluminum sucks the heat away so fast. Use something like silicone or some screws into the wood.