Luckily it's a pinhole slow leak that takes hours to notice
My first thought was to go to the drugstore and grab a syringe. Draw some 2 part glue into it, and inject it right to the back. Then go over top with some form of regular patch, as awkward as it is.
So I ended up getting a syringe. Used a big needle . The small ones won't draw thick glue. This essentially forms a mushroom of glue internally.
Cut a template with paper first . Test fit it while inflated to maintain it's final shape. Transfer the template to the final material.
Cleaned 4 times with MEK . Applied 3 thick layers of glue. Activate with heat . Applied the patch while inflated. Pressed . Patch won't move. Deflated the tube and put the tube on a round surface. I used a small kettlebell to mimic the inflated shape. Pressed again as hard as physically possible . Cleaned with MEK . Let the glue fully cure.
