Lots of people use the heat-shrink connection and tell me that they have no problems at all. They shrink using an incandescent light bulb. I do the nail-knot thing and tie a perfection loop about 2-3 inches past the nail knot -- just as described.

I have found that superglue makes a very hard knot. I use knot glue that I bought at a local shop to secure the knots. It will be hard if it's over-applied as well.

Keep that super-glue out of reach of children! My number 2 son once super-glued both eyelids shut at about age 7. One of the many times I had him at the emergency room. We laugh now, but not at the time.