Sewing zip to knitting

Hi all
i am new here and urgently need some help. i am knitting a bag for my sister for christmas(i know time is running out!)and i need to put a zip in it. what is the best way to do this?should i sew it on with the yarn i am knitting with or with ordinary cotton?
please help

well i have never done it before but i would think trying to get a yarn needle, and the yarn, through the material on a zipper would be pretty difficult. have you tried to see if you can even do it with yarn?

My bet would be to go with heavy thread, also.

The directions in my finishing book call for these three steps: baste the zipper on with heavy thread, then whipstitch the edges with matching yarn, then backstitch with heavy thread over where you basted. So, a little of both. :smiley: