Quilting Thread. Mettler Silk-Finish Cotton thread 40 is ideal for patchwork and quilting and is made from 100% long staple, Egyptian cotton. Silk-Finish Cotton thread 40 is slightly thicker and therefore will allow your decorative stitching to be more visible. Silk-Finish Cotton 40 is also suitable for sewing because the mercerisation process makes the thread very strong, heat resistant and has reduced shrinkage. Mettlers dyeing technology will also give your thread exceptional colourfastness. This makes it an ideal thread for quilting and topstitching, by handor machine.