It is pushing 50 dollars to fill the hole. I bought a 3″ hole saw to cut a 3″ filler but that was a mistake. The 3″ is outside diameter and I needed inside diameter. That was a 15 dollar mistake. I also ran out of co2/argon for the welder so that was another 40 bucks.
So I welded the plate in place:
Ground it down:
Added so filler:
I sprayed the whole back with epoxy primer, follow with a really thick buff layer of filler primer:
A Good day!