piano hinge is the very best
X2
we use piano hinge on our helis in certain areas where wt. vs. strength are a factor. that hinge pin is as hard as a whores heart, hard to drill and dents vise teeth and anvil edges. since its just a dog box, acft grade piano hinge and pins will work fine, but you can't weld it, u gotta shoot rivets instead. solids are better, but since your going into tubing, countersink blinds be required. if u got acft grade rivets, the chance of replacing them are very low unles the rivet puller SUCKS, but most standard off the shelf pullers will pull fine for what you'll need it for. if you choose to go with acft grade hinges made from hardened aluminum, primer both materials first and let them dry. dissimilar metals i.e. steel to aluminum will cause sever corrosion, especially when left to the elements, so a good primer coating it key to ANY dissimilar metal attachment
