Yes, I melted the end of the Spectra cord from BP with a lighter. You are right, it tends to melt back and not fuse together as easily, but you should be able to get something good enough to keep it from unraveling.

As a side effect, you may get a bit of a 'ball' of melted stuff. If that isn't acceptable you'll probably have to try a different approach. Maybe wipe it against a hot object like a soldering iron or something.

-john