Thread strength?
 

The other post about thread breaking has me nervous. The normal thread I usually use for quilting (Mettler 40 wt) was out at my LQS. The store clerk said a spool of the Aurifil wt 28/2 thread was about the same thickness as the thread I was using before so I got it and have been using it for piecing and bound my last quilt with it. So far, I haven't had a problem with it, although I was able to break it with my hands. I noticed most of you use Aurifil 50 wt. Would you continue to use this 28 wt for piecing and quilting or should I cut my losses and buy some stronger thread?

I use Mettler silk wrapped thread since I began quilting many decades ago but I have seen lots of posts from quilters who seem to be very pleased with the product. JAF sells Mettler thread but only online.

50 wt is generally a thinner thread than 28 wt. of the same ply. But you can't judge the strength of the thread by the wt. In fact thread may lose its strength with age, depending on how it is stored. We can break any thread with our hands, but some break more easily than others. If it breaks easily... and that is a relative term... then you wouldn't want to use it. Chances are that your 28 wt thread is fine, but you might want to switch to a thinner thread for piecing because it takes up less room on the bobbin (meaning fewer bobbin changes) and also uses less room in the seam, so that it may be easier to get the correct seam allowance.

Mettler thread is "silk finished", not silk wrapped. This refers to the shiny finish seen on the thread; there is no actual silk in the thread, it's 100% cotton. I wish they didn't refer to it this way to confuse so many sewists. :)

Jan in VA

I used Mettler silk-finish thread for years. Finally, I tried Aurifil 50wt 2-ply. I would never go back to Mettler. The Aurifil left *much* less lint in my machine and is just a much smoother thread. Aurifil 28/2 would be a much thicker (and I assume stronger) thread than the 50/2 I use now for both piecing and quilting, so honestly I would not worry about the thread not being strong enough.

My belief is that the thread breaking test (where you jerk the thread between your hands) is not a good predictor of how good the thread is for sewing. My favorite threads break easily when I do this. I think that test is reliable mostly for judging whether old thread has dry rot or not. In that case, a light tug would easily break the thread -- not the jerk that I gave the thread when I tested it (and which I suspect most people use when "testing" thread).

Edit: I would not use 28/2 Aurifil for piecing because of its thickness. Aurifil 50/2 works perfectly for piecing and makes my seam allowances more accurate.