Mooshie, are you talking about wavy borders or wavy backing? There are at least 3 reasons the bottom border is wavy... 1. when we quilt on a frame, the fabric can get stretched. When you unpin, it looks wavy. Try spritzing it with water or Best Press and walking away for a bit. When its dry, if the stretching was the problem, it will tighten up...some. 2 the borders don't fit the quilt well. Do you measure before you cut? or do you just cut a long piece and then trim? Its important for the top/bottom and both sides to match each other (not the sides and top..the side to side to match...clear as mud? sorry!) If you search on the QB, you will find border tutorials. if not PM me and I will find some. and 3. as we quilt down a quilt, the quilting pulls the quilt top up, leaving you more fabric along the bottom. I used to think I was doing something wrong, but like needing extra backing, its the nature of the quilting-on-a frame beast. You might think of SID and basting the whole quilt before you actually quilt it. This way you can measure and baste as you go down the quilt. I hope this helps. I'm not a longarm expert by any means...School of hard knocks for me!