I did the por-15 on my fuel tank about 2yrs ago. Has held up so far. Had some good size pin holes that i filled in with JB weld then did the whole por-15. I also only bought the cycle gas tank repair kit, just to try and save some cash. It did cover the whole tank though. You pretty much just clean the tank with their cleaners and pour the sealer in the tank, slosh it around and try to get a good cover on the inside of tank. Then pour the excess sealer back out and let it dry. It took a good weekend, just because I let the cleaners sit in the tank for a while. I had a good amount of rust in the tank it kept on clogging my fuel filter, then the tank started leaking. Now I just have to find that 'o' ring for the fuel level sender.