I got my first can of PlastiDip the other day, knowing that I will find cool uses for it. I got a paper clip and gently painted the cracked portions of my iPhone cord with this stuff, overlapping some. It seems to dry completely in a couple hours.
There also seems to be a little shrinkage that occurs when it does dry. This didn't bother me any. I just applied a little extra. One the one end I had to give it two coats.
It does come in several different colors. I think white is one of them. And while that might have looked a little cleaner on this project my main concern was functionality. And I already had the black. Heck, maybe this color-coding of the ends will help distinguish the cable as mine and not someone else's.