I use it all the time for STID but I don't use it in the bobbin. I match that thread to the backing. Here's what I've learned, move it away from the machine on a spool holder of some kind, play with your tension a little if you have problems. Use a small needle, 60 or 70 to prevent breakage. I use smoke on the darker fabrics and the transparent clear on lighter stuff. I get mine from CT.