Oh, watch out for "brass" piano hinges, you might buy them thinking you've got something that won't rust, and then you discover it's got a freaking steel pin in it...
Make sure everything's well braced along the hinge line though, if you've got any sag it will be a bugger to open.
I remember The RoadWarrior..To understand who he was, you have to go back to another time..the world was powered by the black fuel & the desert sprouted great cities..Gone now, swept away..two mighty warrior tribes went to war & touched off a blaze which engulfed them all. Without fuel, they were nothing..thundering machines sputtered & stopped..Only those mobile enough to scavenge, brutal enough to pillage would survive. The gangs took over the highways, ready to wage war for a tank of juice
ohhh if this design sags theres gonna have to be a major probelm that and I plan to arc the cross braces a bit (not much but enough to make it slightly stronger and make water not pool on the hinge). im going to paint it all anyways so not too worried about rust.