Dennis, while flat bar may work. Angle is way stronger/stiffer due to the 90 deg web. I don't recommend flat bar. A big piece of flat, thick stock did work for you but a bar must be angle. Something like 2 x 2 x 1/8 thk. Channel or square will also work. The size and thickness depend on what this problem is. If it's a double wave warped panel or some other change in metallurgy, my bets are off.
We still know nothing about this sheet metal phenomenon, and the size of the oil can, because Coolwhip has left the building.
