Did it blow out?
Not yet, that's why I was waiting to put the pictures, just to make sure whether it works or not.
The hole in the rear is huge, and as it is not "flat", the aluminum didn't seal perfectly at some spots. That's where the foil has come unstuck, due to the hot air blowing out. If the rest of the aluminum resist, I will leave it that way, or probably I will just seal them with a little more epoxi.