If the parts are still fitting together, use a slow epoxy (30 minute or slower) and cover the areas to be reinforced/reglued with a thin coat. Now take your heat gun and gently heat the area to the point where you see the epoxy suddenly thin down and seep into every crack and joint. At this point it penetrates into every nook and cranny and, due to the heat, will set up in less than an hour. Leave it set up overnight to let it gain full strength. Even 5 minute epoxy does not retain full strength until after it has set for 12 hours or more. The times printed on the container mean "time to be tack free" not time to fully cure.