Rusty corrugated flank

[Birdhouse]

So.
I discovered that the corrugated section between the actual rub rails on the left side ahead of the rear wheel is rusted to lace.

It looks like 2 adjacent windows had a long term leak. There was a very old repair in the area then it got worse.

I hit it with a wire cup brush on the angle grinder and it turned out about 3x as bad as it looked. A bunch of spots that barely looked like freckles blew out.

It would be easy to cut it out and slap a chunk from another bus on the hole and close it up. Too bad the busses I pulled the rear crown and some odds from have already been scrapped....

Lol.
Do I smear bondo in this thing like my grandpa did to the saguaro cactus to plug the woodpecker holes or is there a better idea?

Anybody wanna cut a chunk out of a junk bus and throw it in the mail?

Thanks yall

[Birdhouse]

Well I found out I was mistaken
The herd has been thinned from. 5 to 2 but he still has junk to cut on. Hooray

Funny shaped patch, here I come