I like to use a little microballoon in my epoxy for hinges. I also use two hour epoxy. I set the surfaces so that I can just allow the epoxy to run into the hole after I lay it into the little trough I cut for the pinned portion of the hinge. I go from hinge slot to hinge slot adding a little bit as it soaks in. Then I place the hinges in and attach the surfaces and lay the piece flat so that the epoxy niether runs into the wing or out of the slots.

The microballon seems to allow the epoxy to get a better grip on the imperfections of the hinge. I have never lost a hinge this way.

Mark