Sewing Machine Needles - Choosing the Right Size

In my last post I told you that I had picked up the fabrics to start a new quilt. I've actually come along a good bit on it and today I was sewing together some sashing strips to put between the blocks. The quilt uses batik and cotton and the batik is thinner than regular weight cotton. I was having some problems with the batik fabric coming through on the bobbin side of the seam. So I made a little video to show you what I was doing and what I did to correct it. Hope it helps!