When i worked as a weldor i was asked to go and
sonic the bottom of a big Diesel tank that leaked.
And see how big part of it that was rusty.
It sonic full 6mm everywere till i found a sheetmetal
screw
![Shocked :o](http://fepower.net/simplemachinesforum/Smileys/default/shocked.gif)
. Somebody had drilled a small hole and
used a sheetmetal screw to plug it and voila they had
their private gas station. Just bring a philips screwdriver
and a bucket