You dont need a tube just wrap glue ends then heat and it will shrink
The guy's that put the shrink on the boats use a tiger torch (flame)
They do sell a heat shrink tape for joining ends but non of the pros use it
If you practice it will stick to itself when you heat it.
I'm going to do one pack this weekend i'll post pics.
Not everything that can be counted counts, and not everything that counts can be counted.
- Albert Einstein