Welcome sak45acp. Good first post. How about introducing yourself?

We have made the cardboard box oven and used it extensively at camp. It lasted for about eight months of monthly use until an small undetected tear in the foil caused the box to catch on fire. We put the fire out and finished cooking, then retired the box.

A couple of differences with our design...

We used a propane burner at the base instead of charcoal. That coupled with a thermometer allowed us to set very precise temperature controls and make adjustments on the fly.

We made everything from desserts to hot dogs to a huge roast. It worked great. And the oven was strong. We used a scavenged broken chair as the base of the oven. That way, the bottom was raised making it easy for the propane connections and temperature adjustments.

A couple of important tips. Elmers glue is the BEST glue for these types of projects. Apparently it is safe and heat friendly. Second, use a diffuser above the heat source to avoid burnt bottoms of whatever you are cooking. We installed aluminum racks in our oven held in place with the ever handy paper clip (drill the rack with a SAK awl, and thread the clip through as a stopper). And we used a large metal tray as the diffuser.

It was amazing how well it worked. I will see if I can find some pictures of it in action.