Liquid Electrical Tape for Deans

I have used the liq elec tape - I use a 100' ext cord for the leaf blower/edger and from the days when I had a elec mower I nicked it in a few spots. Thats seems to be the perfect use for that stuff - made for a great repair. But it does not store well or for long either.

I make sure I push the shrink down on deans as they shrink, but I still get the gaps as many times as not. They've never caused probs and I've never done anything about them either. I