Originally Posted by
magicmoonmusings
Today I was testing my thread stash using the 'tug test' and when I tried my brand new - purchased 3 weeks ago - spool of Aurifil 50 wt I was shocked that this stuff breaks SO EASILY. I have 20 year old Valdani and Coats & Clark that are much tougher than this stuff!!
Coats & Clark threads are higher threadweight (likely 40 wt ) and possibly poly-core to 50 wt Aurifil that is all cotton. The fine-ness of Aurifil is what makes it great for piecing - it disappears into the seams. Valdani could be anything - they make a variety of threads, including a long-staple Egyptian cotton 50wt that is basically the same thing as Aurifil 50wt. Ditto Gutermann, but it's most often associated with a poly thread (Mara) which is inherently stronger than cotton.