Take your zipper, I made mine with a 12 inch one but you can use it any length that you want.

With some fabric scissor, cut the fabric off the zipper, just leaving the teeth.

Now, pull all the extra fabric with your fingers to clean it up.

Then take your lighter and burn the rest of what is left on the zipper, careful with this specially if you are using a plastic zipper.You don't want to burn it all. If its a metal, let it cool before touching it.

Now take you some of this and put the on to the end. If the zipper its too wide you can burn it a little and mold it by touching while its till hot. Dip your fingers in water before touching it.

Now put the necklace closing, by getting you metal tongs and squeeze then closed.

Next, put the lock you desire. Secure it in place, making sure it wont fall out.

And hazaaa! You have a zipper necklace!!

(Mine had a little accident, because I was distracted and burn it, it did broke and I had to reattached it by melting it and gluing them together.)