Product review (3 stars): Pretty good.
If you think the donut spare tire is a permanent fix you will like this stuff.  This will delay having to purchase a new rack, but it won't make your old one look like new.  It takes 3 or more coats for good coverage so plan on a day of fettling.  It doesn't smooth out when cured so spend extra time making it pretty when applying. It's a small bottle, but contains a lot of goo.