Yeah, that's proven to be false. Old wives tale.

piecing quilts and sometimes bags. but I also use poly for piecing as well, depends on the project but I mostly piece quilts with cotton unless I am doing heavy machine embroidery ofver seams then I will use so fine. I like poly for FMQ but I will use cotton but only king tut for FMQ

I normally piece with cotton and quilt with poly since I like the shine. I just got some non-shiny poly and it looks like cotton and works for piecing.

It just makes sense to me to use cotton thread on cotton fabric and polyester thread on synthetic fabrics. If you've ever sewn a hem on polyester pants, with cotton thread, it lasts about 3 months before the poly rubs right through it. I had 2 wedding quilts (from 1984) where the polyester thread cut through the seams. So I only use cotton on my quilts.

Think about your question. For hundreds of years there was mostly cotton (linen cam in too, but for embellishment and not quilting. I learned to use cotton and that is what I use.

I'm one of the people that uses only cotton thread. If at all possible I like to use 50 wt. to piece with too.

I only use cotton thread in my quilts. I use polyester or cotton in making bags, clothes, and home decor items, but since learning to quilt I have a larger stash of cotton thread than polyester.

I'm curious, if you use polyester thread in your quilt, do you worry about ironing at high heat?

I think a lot of the cotton vs. cotton/poly hangs around from the 'olden' days. A lot of the same ideas for cotton only fabric vs. cotton/poly fabric. There were very valid reasons when we washed things in very hot water and there was a very big problem with shrinking. Also, the quilts were made to last forever and be passed down. Today, most people wash most things in either warm or cool water so shrinkage is much less and as sad as it is, our quilts are not going to be kept forever. So, many of the old rules don't really apply today. I think it is more a personal preference and how you were taught that is the biggest influence today. The only time that I plan on using all cotton everything is when I make a quilt for an infant. Because I know this will be washed in very hot water, will probably have many staining stuff on it and may even need additives in the wash water. Poly tends to hold onto stains. Like I always tell my students - it is your quilt, you decide what you prefer to use. Olden days crazy quilts had bits of velvet, lace, cotton, feed sacks, satin, everything they could find in them and they are still around!

I am another that uses whatever she has in her thread cabinet. I think that cotton thread is just fine for quilting.

Wow! I haven't OWNED polyester pants since 1978!