well i bought a ball of the # crochet cotton that Patrice mentioned. I really thinks that's it. I haven't had enough time to play with it but I tried it in the bobbin and ir worked and looked just fine. Tried it thru the needle and it kinda wadded up on the bottom, had regular thread in bobbin. I figured if I used it on top and bobbin it would be too heavy but I may try it or learn to quilt from the bottom!