Do I have to glue the back of my rug?
If you are making a wallhanging you don’t have to glue it.
If you cut it out of the frame it will most probably curl/fold together. Follow this link how to take care of this.
If you are making an actual rug for the floor you definitely should glue it.
Here is why:
With your tufting gun you are basically just shooting little pieces or loops of yarn through your tufting cloth. There is no knot or anything to hold the yarn in the fabric. That’s when the glue comes in. Without the glue your rug would loose more and more yarn over time because it will be pulled out while walking or vacuuming it. So you glue your rug to make your yarn stay in place.