I have had two quilts that the quilting thread broke after years of use. One I used something called "star" cotton thread on, it was supposed to be for quilting. The other quilt I believe was king tut varieated thread. Both of these quilts were used and washed. One had dogs jumping up on it. I now use Superior threads so fine for the bobbin in most of my quilting on the long arm...when I first started out on the longarm, I used OMNI. I have a good supply of that and am debating with myself over what I can use that up for. It is a a good poly thread with a matt finish but it is thicker than the so fine. I would like to use it up...I am not a great quilter so need to find some "busy" quilts to use it up on. umm...I have the big cones of it so each cone will make a few quilts.