Hi there Mike.
Last year I got an old awning and it's rail of an old late 60's tent trailer.
I used Butyl Tape between the aluminum rail and the fiberglass body of my 74 Boler
So far it has worked great with no leaks
, and I don't anticipate any leaks
in the near future. Butyl Tape stays soft and tacky forever!!!
Here is a picture of my outside light
I also installed using Butyl Tape. You can see how it oozes out and provides the perfect seal.
For those of you who have installed an awning rail before, did you use putty tape or silicon? And, how has it held up for you? I am in the process of installing mine and could use your help.