An FYI in regards to using shrink tubing for either repairs or loops. I have done both and still do, but I've have noticed a few drawbacks:

1. If you use too much heat, you can cook the core of the line or melt the coating so much that it gets hard. If the coating discolors and turns brown when you shrink the tubing, you applied too much heat.

2. Misdirected heat will BURN the coating. I don't like using a lighter and use a butane soldering iron instead, putting the shrink tube NEXT to the catalytic element to shrink it.

3. I have found that the coating melts and fuses WAY better when the line is new and squeaky clean. The several attempts I have made to replace a loop on a well used line with ground in dirt have been less than satisfactory. The coating just doesn't want to melt and fuse the way it does when the line is new no matter how many times I clean it, even with a 3M pad and cleaning solutions.

YMMV