A few years back I decided to replace some of the through hulls and seacocks that came with my boat, Finnsailor 38, built in 1978. Well, it turned out probably to be a waste of time, but I still did it. The bronze through hulls and seacocks were all fine, and as strong as the day they were put in, and they were all bedded with some sort of green colored silicone. I don't know if that was the original color or the caulk had turned green after all these years, but it looked, felt, and acted like recently applied silicone. No, it didn't have the bonding tenacity of 5200, but I could see no reason why that caulk wasn't as good as new.