Forget JBWeld. If you want to put thousands of miles on these pedals, you are going to have to address the hardness issue. If you are using them for occasional rides, just smooth down what you have.

The problem is that these pedals were never designed to be repaired. Any repair more involved than cleaning up the cups or replacing the bearings, axles & cones will require a great deal of money, as well as an imaginative machinist. I doubt there is enough material in the barrel of the pedal to hold a loose cup, even if the original were machined down to accept it. Then you have the issue of axle length, which isn't trivial. If you were a machinist (or had one who owed you a big favor), it might be worth exploring other options. However, you wouldn't have posted here if you were or had.

I hope this doesn't come across as unsympathetic. My wife has an all-Campy bike, except for the pedals which are mid-range steel Way Assautos. She likes them, and I dread the day they wear out and I have to deal with the same issue you have!