Thank you for posting this! Just Sunday, I took a spool of white 100% polyester thread and filled a bobbin and used it to sew some blocks together on a baby quilt I am making. I was worried about the tension issue with cotton on the top and poly on the back but the stitching is perfect. I thought that was the only thing I needed to worry about. I got several spools in a box when I bought my serger and was just going to use them up. Now I will remove that bobbin from my machine and get rid of the poly thread!!!