I think we need to get a constipated mathematician ( you know they could work it out with a pencil ) to give us the guts of the matter . It would be interesting to see the pressure required to blow the top off a healthy jug I imagine would be pretty big . Has anyone studied the fracture for tell tale signs of a flaw . This could have been discussed before but my memory is shot from to much of the good gear in my younger days ! Cheers from the fractured pope