I'm gonna make a stick of dinamite about 3 feet long and 6 inches in diameter, weve rigged a remote detonation device with one of my old cell phones. and a backup 5 min fuse. were gonna make a crater aprox. 75 wide and 8 feet deep with it. been working on ir for all of last week. just some nice sewer piping with caps at each end. we got a nice spot about 1/2 mile away on a hill to watch it from.