If its any consolation, I did the exact same fin (1 from left of upright) trying to get the flywheel off my sunbeam - I was thinking about reattaching and put a little glob of selleys knead it epoxy steel weld,
It stuck to the crack and is like concrete - probably more or less made up for weight loss
Took it out today, gave it a light wash and clean - started first pull after 2 months