Re: What did I do
That is a super-simple fix. I wouldn't even bother to remove the leg.
Sand the paint off ?" back from the edge of the cav plate break, (top and bottom) clamp a copper strip under it, also clamp a cut piece of 1/8 aluminum plate to the copper to leave a 3/32" gap, then tig weld from the outside to the middle, do ?" at a time alternately to limit warp stress.
The copper will allow 100% penetration, prevent oxidization, and leave a smooth bottom surface. The aluminum weld won't stick to it. Promise.
No copper strip in your junk box? Flatten a short piece of ?" copper pipe with a hammer.