i took 2 pieces of plywood (hardboard) one 6mm and the other 8mm.(for the back 6 mm is enough.for the table 8mm is very strong.12mm have a big extension cause of the thickness.(from my choice iam satisfied)i used as a pattern the old piece from the door and marked the points of the existing holes..after i took some aluminum rivets with internal thread (there are also in stainless steel but they are too hard for drilling if needs to the future to take them off)the riveter is too expensive so i used one bolt ,one washer ,one grover.keep with one spanner the nut and turn the bolt with another spanner expanded the rivet
i installed the rivets to the holes of the door as u can see here after and M6 bolts usedto the thread of rivets.http://www.youtube.com/watch?v=svQXAVP_gss
used i big hinge (made from soft metal for flexibility and bronze covered) for sharing all the force equal and with screw eyes join the 2 pieces.for more strength used sikaflex 291 and M4 bolts with nuts every 20 cm(if the screw eyes because of the thickness of the wood destroy the holes and the wooden thread the bolts with the washers and the nuts keep the construction safe)the 2 pieces of marine rope is strong enough to keep the 2 pieces of wood in 90 degrees angle as u see with the 20 kg nice girl load.and 2 small lights 12v make beautiful my nights..