This is a great technique to use if all the beads in your piece have large holes. It will not work at all if even one bead has a small hole as their is no way to get that bead on. You can use any thread you want - I use cotton tatting thread, but yarn or any other string would work equally as well. This is a very strong cord that I can't imagine ever breaking. I've made hundreds of necklaces with this style and never had one break before.