Product review (5 stars): Was not able to test how well it could hold up in the dishwasher.
I read many previous reviews before buying. I bought the larger size bottle. I used a dremel tool with these small diamond tipped tool bits (can buy on amazon, just search for "diamond tip bit tool" - cost under $5) to effortlessly sand down the rusted portions. I worked quickly and I had no trouble using this product. However, after I used about 100 of the caps, I flipped my rack over and realized much more of the bottom rack was rusted. It was rusted in places where I could put the Goop, but could not use the caps. The dremel made it easy to sand, however, there was so much sanding needed, I got tired of it even before I flipped over the rack and saw that the bottom was rusted too.

I finally gave up, threw the rack in the garbage (of which a new one was going to cost me about $150) and I just bought a new dishwasher. The new dishwasher's rack, I believe is either vinyl, pvc or some other material that is not metal on the inside. Cost me about $450, my old dishwasher was about 12 years old.