If the theory is that hydraulic friction created the hole then the metal either side is going to be thin. Good luck brazing a screen door. BTDT on a 356 where the panels were so thin from the obvious rust that the weldable metal was a long way from the target. Typical of metal panels.
This is a pipe, I know. So whey not cut it in two at the hole and take a look? You could cut out a section and fit a new one. I have seen 90º bends for sale in just about any metal and diameter. If you get lucky you can get an ID that fits snugly over the OD of the pipe. If not then it can be expanded.
https://www.youtube.com/results?search_query=how+to+expand+a+tube+with+no+ tools
Interesting article about hydraulic friction
(actually the article reached with mispelling was better
)