[71GMC_3/4T]

"The only problem with this thread is the people that did it the wrong way don't get to reply. " <-- Tom Hand

Ah, good point Tom! LOL on that one, even though it isn't funny.
My shop teacher way back in HS told us the military used to pump exhaust from a running diesel into the tank for a while before welding it. I like the dry ice idea myself. But like Tom says, take it to a shop! Otherwise fishuntr, we have to wait for your next post and worry about you...