Many years ago. Foam is easier than cork, but not as desirable. Cork comes in smaller 'disks' that, when done, need to be sanded to shape & smoothness. Both need to know the diameter of the rod's shaft so you can push on and glue. That's about all I can remember. (At the time, 51 years ago, I owned my own sports shop and had wholesale catalogs to choose what I needed at cheap prices.)