I use Superior Threads So Fine 50 wt for all my piecing. I only use beige and gray, so I have big cones of each. Polyester so hardly any lint, but it stitches like a cotton.

Aruifil and I like to buy the big cones in a neutral color makes my life easier.

Lately wonderfil but really anything mostly cotton. I quilt with the polyesters bit don’t piece with it.

BottomLine
 

I was looking at their thread BottomLine and they recommend using a low iron. When piecing I use a very hot iron, so their statement is worrying me. I normally piece with an all-purpose polyester and have never had any problems, so maybe I am over thinking this.

I use Aurafil 50 wt with my Juki TL18 QVP, although it works with pretty much any thread. My wife's Janome 9400 is a different story, but we've found that Superior So Fine works pretty good for piecing and Isocore for quilting.

Me too! A lot of my quilts have small pieces and I think BL, which is a fine 60 wt thread, helps with accurate seams.

My two cents, you are overthinking it. :) I've used BL for years and have used a very hot iron with no detrimental effects at all.

I generally piece with gray Aurofil 50wt. that I buy in cones, check out the prices at Bear Creek online, I have found them to be the most reasonable. But I have also pieced a quilt using Wonderfil's Decobob on top and bottom and really liked the results of using such a thin 80 wt. thread. I went to an "infommercial" thread class at a local quilt shop that has begun carrying the line and saw examples of using both Decobob and Invisifil which is 100 wt. for piecing and quilting. The difference in the feel and weight of the pieces was amazing! When I run out of my cones, I will probably switch to the Wonderfil. The Decobob is a cotton wrapped polyester. So far, I have just sent my quilts out to be quilted so I can't speak to what I might like to use to quilt, but again, I was impressed with the drape of heavily quilted pieces using the Invisifil.

I was looking for 60 weight thread and spoke to them at Superior Threads. They said not to use Bottom Line thread in seams if you like to press your seams as you go, which I do. The poly thread does not hold up well when pressing with high heat like we do with cotton fabric. I found Presencia thread at Red Rock Threads online. It is 100% long stable 60 weight cotton. It does come in 50 weight so check closely if you order. I like the 60 weight. It does make a difference in the bulk of your seams.

I didn't realize that was the recommendation. I use a hot iron with no problems so far.

When I started quilting I had a large selection of partial spools from garment sewing. It was a mix of 100% cotton, 100% poly and also blends. I asked a quilter if I could use these for piecing and they said no problem. I will say that when I ran out it was recommended that I use Aurifil 50wt and I wouldn’t use anything else now. I am able to purchase from my LQS and it is fine but strong....there may be something better but for me it’s one of those if it ain’t broke don’t fix it situations!