Hey people i" ve been tigging along time and using wp17 flexes forever about a month ago i had one blow up like a bullfrog whenever i opened the gas valve i figured what the heck it doesn't owe me anything so on goes a new one and two days later i fired up a new one go to do some tacking and hear and feel a slight crack noise now this one starts too leak and blacken the welds whats up with this any ideas?