There is the possibility of finding a section of tubing that is a tight interference fit on the existing flywheel and then heating it up and shrink fitting it onto the outer rim of your compromised flywheel. Such a fix might well last a very long time .... or not.
One of the problems with spot repairs with something like JB Weld is that it will almost certainly throw the flywheel out of balance, which is important.
I'm actually with Dennis here .... why not just replace the flywheel and be done with it!?!?