If it was an FPE you wouldn't need the 2 x 4Parts were melting and dripping out the dead front but the breaker wasn't tripped! Been a while but I suspect it was a FPE....
I really wonder about that statement. An ammo box has a rubber gasket around the top and the top clamps down so tight that an air tight seal has to be broken like a coffee can. If you have a .50 cal can and you have a high pressure day, you may need something to break the seal with.By the way, a show on discovery said duct tape is really duck tape, developed by the army to seal ammo boxes for WWII, from water intrusion "like a duck's back".