Superior Threads
 

I purchased Superior thread Bottom Line for use in my bobbin. I sew on 100% cotton and wonder what would be a good top thread for quilt piecing. Botton Line is WT 60, very fine. I generally use a WT 40 thread on top for piecing but wonder if that will create a tension problem. I only use polyester or rayon for piecing and am interested in your recommendation.
Thank you!

first, i would recommend you switch to cotton thread for piecing, too.
i have read that rayon thread will not stand up as well to frequent washing.
some brands of poly are ok for piecing, but some could cause more wear and tear on cotton fabric.
(expect lots of backlash against that statement from devotees of poly thread. lol)
50wt is good cotton. 60wt is better, although usually more expensive.

My favorite thread for piecing is Aurofil 50wt. Have you considered using Bottom Line for the top thread also? I don’t see why that would be a problem.

Here's a backlash! I've used primarily Dual Duty, a cotton covered poly thread for most of the last 40 years. I've heard all along about "oh that's bad, you must use cotton!" No, you don't need to. In fact, I can show you my first quilts that show that no, the evil polyester did not saw through my fabric. I can show you my collection of wooden spools, on most of which the cotton is rotten and can no longer be used. If it can rot on the spool folks, it can rot in your seams.

I started using the Superior prewound bobbins for quilting on a long arm and loved them for several reasons. For one, we couldn't wind a decent bobbin on the Pfaff to save our lives. I love the extra amount of length in the thinner threads/prewound spools. I have used pretty much all possible combinations of various threads (Dual Duty, King Tut, Coats Machine Quilting, etc. etc.) with Bottom Line and always had good results but I always do a test sample first and adjust what needs to be adjusted.

I am currently using Bottom Line (I bought the huge cone of white), and will be trying my top quilting with this too with a pair of preemie donations quilts I have to quilt down. I no longer have access to the long arm I was using, but I was given a modern Bernina 820 with the warning that it was a bit fussy with threads but it liked Aurifil. I like Aurifil too and we are doing just fine.

I have paired Superior's Bottom Line in the bobbin with So Fine! in my top thread without any issues. I will admit to doing this only twice, so my quilts haven't gotten a lifetime of wear, however, my Bernina absolutely loved the thread. And I loved having less lint. The only snag I came up against is the thread is a bit more slippery, so I tended to backstitch my seams. But, all things considered, I'd use Poly again for piecing in a heartbeat.

The utility quilts I make for the kids are quilted and pieced with poly thread in bobbin and cotton thread in top, vice versa , or the same in both. They have been washed and used a lot and no problems with broken threads or pulled apart seams. I use Superior, Aurifil, Wonderfil, and Glide.

I use BottomLine top and bottom for piecing. It takes up less room in the seam, which makes it easier for me to piece more accurately.

I use BottomLine in the bobbin for most of my quilting. I use whatever gives me the effect I am looking for on top. I have used Aurifil, various brands of metallics, invisible polyester, Isacord, Floriani, and my favorites SoFine and King Tut. I just make sure to check the tension balance on a sandwich scrap before I start and adjust as needed. You limit yourself too much if you only use one yep of thread.

So fine top and bottom works beautiful, no back lash also so fine in top and bottom line for bobbin great tension.
--Recently was given cone of glide thread by fil tec with matching pre wound bobbin This is beautiful thread bobbin has magnetic core so far no problems again beautiful stitches.
I was also given their cotton thread with matching pre filled bobbin by fil- tec called Magna Quilt which is my preference however very hard to find.

I use SoFine #50 in the top. I find no problems with piecing or quilting with a poly or poly blend. I often use Coats Duel Purpose for piecing and always for attaching binding by hand. On the long arm I prefer a poly, SoFine being my "go-to", but also Permacore and Glide. I carry some cones for people that think only cotton can be used--but most are #30 or 40 weight and linty.