The threads stripped out of the drain plug on my Hamburger oil pan in my 70 Dart race car. I drained the oil out all week, and decided to weld a 1/2-20 nut. I just finished welding, when I guess was a combination of race oil and fuel fumes blew out the drain hole with a bang and coated my welding helmet. Couldn't see out of it , and could not get from under the car fast enough. It did work, but I would not suggest welding in the car