Cranberry,  After thinking about my post for making disposable aluminum ovens, I decided to go look at my old Boy Scout stuff and re-examin the construction.  I was a little off on the details!
Anyway, this is how we made them:  2 square disposable baking pans, 1 round disposable pie pan, 1 bolt (2" long), 2 washers, and 1 nut.  You make the oven top by poking a hole in the center of the pie pan and square baking pan.  Fasten the 2 pans together bottom to bottom with the bolt, washer, pans, washer, and nut.  The round pie pan holds the coals as the lid for your oven.  Place on top of the other square pan to bake.  You can open the top of the oven with a pliers by grabbing the end of the bolt to check what you're baking.  I just got a little confused with my other dutch oven invention.  The dutch oven frozen pizza baker.  But that's another story.