I just did one myself, nowhere near the advanced repair of yours :laughing: (
Nothing but High Tech around here ) I just got a tube of that high heat steel repair putty and battered it on.
Mine had rust thru at an end seam so there was no way to put a steel patch on it. The material cost 4 bucks, I really had no expectation it would work, but figured it was worth a shot, it was in a hard to reach spot, just enough room to get my hand/fingers in.
Let it set overnight and it worked great
When I was young and had no money, some of my smart arse friends called me Hillbilly, cause of my unorthodox repairs. Wood screws, duct tape and baling wire was on everything I owned

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Duct tape & bailing wire should fix most everything. )
If I had self tapping metal screws and a battery powered drill/ driver back then, I could of done miracles :laughing:
JB