The Difference Between Cotton and Poly Thread: A Hard-Hitting Interview

What's the difference between cotton and poly thread? Both are great sewing options, but each one has difference strengths and weaknesses.

Ever wonder what's the difference between cotton and poly thread? Both can be great sewing options, but they are pretty different in terms of strengths and weaknesses. Lucky for you I'm a part-time P.I. with an insatiable drive to answer quilting's toughest questions and solve our sewing mysteries.

Last week I got the chance to sit down with both Cotton and Poly Thread. At first they were hesitant to chat because of past misunderstandings, but once we broke through that barrier, Cotton and Poly opened up in an unexpected way.

The Big Question: What's the Difference Between Cotton and Poly Thread?

What's the difference between cotton and poly thread? Both can be wonderful for sewing, but each has very distinct strengths and weaknesses. | Suzy Quilts

Suzy: So tell me a little bit about your past and upbringing.

Cotton: My story is probably one you’ve heard before. I grew up in a large family surrounded by nature. As a cotton plant, I knew I would eventually get picked, but that doesn’t mean it was easy. After I was picked, I was also combed and thoroughly cleaned. Once all of the dirt and excess plant materials were stripped away, my fibers went through roller after roller generating narrower and narrower bands of thread. Ouch. Let me tell you.

Poly: Cotton, you think a few rollers were painful? In my process, I’m stretched to the limit! Sorry to interrupt, but I think my background is what gets people the most confused, so let me clear a few things up. I’m considered a “synthetic” fiber because I didn’t have a cushy, natural upbringing like Cotton. In fact, I’m extra tough because I was born and raised in a factory.

Through the process of modifying petroleum, I showed up to the thread manufacturer as hard chips, which were then spun and loosely drawn together into long polyester filaments. My filaments are then stretched to their limit – obviously my least favorite part of the process. But once I was stretched, I was cut at my weakest points so that only the absolute strongest fibers SURVIVE!

S: Poly, I’m going to have to ask you to step down off the table and stop flexing your biceps. I think we get the picture.

P: Apologies. Let me continue – the strong bands are combined to make a narrow, even, high-quality fiber. Did you hear that ladies??

S: Poly…

P: [wink] My fiber is then twisted up and stretched by machines until it’s ready to be wound onto cones. Ta-da!

Favorite Sewing Notions!

What's the difference between cotton and poly thread? Both can be wonderful for sewing, but each has very distinct strengths and weaknesses.

C: Well, before I was interrupted I was about to get to the exciting part of my story – FIRE! Once my fibers are twisted and spun to create a single thread, I’m singed over an open flame and then dunked into a special elixir called caustic soda!

P: OK OK...that’s pretty cool.

C: Oh yes. That strengthens me and makes me extra shiny before getting wound tightly around a cone.

S: Wow. It sounds like both of you have had some pretty life-changing experiences. Cotton, a rumour that’s been swirling around sewing circles is that you tend to be a little inflexible. To be blunt, some would even call you “a stiff.”

What's the difference between cotton and poly thread? Both can be wonderful for sewing, but each has very distinct strengths and weaknesses.

C: I’m glad you brought that up because that’s a rumor I’ve been wanting to address for a while. Just because I don’t like to get mixed up with spandex, rayon and other party-loving fabrics, doesn’t mean I don’t have great things to offer. As a natural fiber, I like to work with other natural fibers. Yes, I am not as stretchy as Poly, but what I lack in flexibility, I make up for in softness. Just feel me!

S: [strokes Cotton Thread] You aren’t lying. Silky soft! Now Poly, I hear you have some pretty well-rounded interests. Tell me more about that.

P: Suz, can I call you Suz? Because of my past, I’ve gotten a bit of a “bad boy” persona, but that couldn’t be further from the truth! I’m a people pleaser and love collaborating with all types of fabrics. You name it, and I’m there! Even though some would say that you should pair natural Cotton Thread with natural fabrics and me with only synthetic fabrics, that’s just not always the case. I know a lot of quilters who prefer to use me. Especially in their bobbins. I’m greeeeat in bobbins.

S: Oh yeah? Why’s that?

P: Less lint, baby! Cotton may be a bit more durable under the heat of fast sewing, but I make waaaay less lint. I’m virtually lint free! And yes, I’m a bit stretchy, but you know what that’s good for? Clothes! Clothes LOVE me! Knit tops, Nylon skirts, Jeans, oh especially Jeans. They need me.

S: Thanks so much Cotton and Poly for sitting down with me and opening up. Are there any parting words you’d like to share?

C: I’d like people to know that even though I am a more expensive option, I promise to work hard, not break under pressure, and bring softness to their heirloom projects.

P: When it comes to quilting, I’m a great companion for piecing. I’m strong. I’m tough. And I don’t make a huge some other Threads.

C: Hey!

S: And there you have it, folks. Two great Threads doing their best to help you with all of your sewing needs.

Next time someone asks you what the difference between cotton and poly thread is – you'll know the answer first hand.

What's the difference between cotton and poly thread? Both can be wonderful for sewing, but each has very distinct strengths and weaknesses.

57 thoughts on “The Difference Between Cotton and Poly Thread: A Hard-Hitting Interview

  1. Nancy says:

    Well super interesting, so which is your preference for quilting Suzy? You know someone had to ask why not me? 😂

  2. Zanymouse says:

    Great interview! I noticed that the primamdonna, cotton/poly blend, must have been busy getting her hair done. Thank you for brightening my day!

  3. Judy says:

    I have one question that was not addressed. I have heard that Poly tends to cut the fabric fibers over time and makes the quilt top disintegrate. Do you know if this is true or not.

    • Suzy Quilts says:

      That sounds like a rumor…and I have a hard time believing it to be true…however, I can’t say with 100% confidence that it can’t happen. I would guess, with 90% confidence, that your poly thread will cooperate just fine.

      • Grammy Judy says:

        Thanks for the verification, I asked the same question at a favorite quilt shop and was told the same thing. I also love using the rayon variegated threads for decorative stitching and wish more were made with cotton or poly as my machine does not always like the rayon thread.

        • Christina Harrigan says:

          Have you tried Madeira Poly-Neon or Madeira Cotona thread (yes they have variegated!) I just love it and so do my machines – I use mostly BabyLock and Bernina, sometimes a Viking, Singer Featherweight, and my daughter uses them in her Kenmore.

  4. Mike says:

    I love the wit and humor you brought to the table with this post, Suzy! Definitely a fun read.

    I bought Gutermann thread starter sets in both polyester and cotton, thinking for sure I’d be a cotton boy through and through. But you know what? I go for the polyester version the most. It works really well for me. Not that the cotton thread is bad; it’s just not as “fun” for me to sew with.

    Thanks for making me smile and think today!

  5. Marty says:

    Fun ~ but wish you would also add a small comparison chart so I won’t have to make one myself for a future quick-choice read!

  6. Tonya Wohlever says:

    I love the idea of using poly in bobbins (I use all cotton now- for quilting)…but I do not prewash my fabrics- so will cotton thread on top shrink a bit while poly on bottom doesn’t…causing puckering??? This may be a rumor too. Great article!!

  7. Caroline Adams says:

    When I started quilting, poly was a bad word. Some 20 years later I still use cotton for piecing and general quilt construction and quilting. However, I do like poly for decorative stitching and applique, it has a bit of a shine to it. Do find it best to have same thread on bobbins.

  8. Carissa Small says:

    This is incredible. I sometimes get really bogged down with the information on various quilting blogs but yours is always my favorite to receive. I like your aesthetic, your humor, your beautiful modern quilts, and your informative ways. Thank you for always being awesome!!

  9. Jenna says:

    You are so imaginative. I always love reading your posts. You make reading a seemingly uninteresting topic into the funniest and easy to understand thing I have read in a long time. Lol. Thanks! Love it! I aspire to write with at least half of your wit and humour! ❤️

  10. Noe says:

    Hahahahaha! This was amazing. I’m the worst because I always just buy what’s on sale and force-fit it to whatever project I’ve cooked up! Ugh. I should probably grow up and change my ways and really THINK before I stitch. Womp womp! Thx for contributing to my evolution as a human, SQ… 😬😬😍

  11. Aimee says:

    Sew for us newbies and trying to buy it all & being budget minded, with poly definitely cheaper than cotton, do you suggest we give poly a try? What about poly/cotton? What weight for cotton is good overall to have?

  12. Irene says:

    Hahaha Suzy love this. Thanks for sitting down with these two guys to get that sorted out. I might have to give Poly a try, up to now I’m a cotton only kind of girl 🙂

  13. Karen Alexander says:

    Well, when you sew with a machine, LINT HAPPENS! I say, get over it! Sewing machine engineers understand that, and every sewing machine is designed to handle the process of delivering threads from spool and bobbin through the needle to your fabric… No problem! But do you really want to sleep with a petroleum product? I’ll take the comfort of natural cotton any day!

  14. CeCeC says:

    I began my quilting venture as a cotton “purist.” After sitting for hours picking out popped quilting stitches on a 3 year old lap size quilt (little used, if I may add) that I had quilted with a premium well-loved cotton thread, I will forevermore use polyester thread for quilting. May have been a fluke, but I will never risk that again!!

  15. Sue says:

    Oh my gosh, I just asked this question in one of my Facebook groups.. I am piecing a quilt top, i am ok using poly thread ain’t i? I have 2 cones of this thread and wanted to use it up….love this interview….thanks for sharing…

  16. Rondalyn says:

    What a great way to take a slightly dry topic and turn it into an interesting and informational topic that will stick in everyone’s mind without much effort. Thank you.

  17. Sheela says:

    I came across yours lovely site by chance because I was looking up on what was the difference on types of thread as I hv always used Poly thread and never cotton even though I hv cotton in my sewing box they are left unopened 😯 much to my dismay after 25year . So ,I would say
    Thank you very very much for that lovely lovely write up ,Suzi on the “interview with Cotton and Poly” it gives me a bit of confidence that my work with ‘Poly’ has been a good choice after all. I did a quilt for my daughter about 20 years ago the only thing that us coming undone is one of the stitching at the ends which looks like the material is wearing. It is a very thin material not quite built for quilting standards these days. It was a choice of my eldest daughter who wanted to give to my youngest. It has embroidery work on it as well. So I will be doing, some repair work on it soon to make sure it doesnt come apart. All the threads I hv used in my life has been Gutermann thread.

  18. Melanie Ezmirly says:

    Hi. Just starting to quilt…ok, right now just in the process of gathering fabric, then will take the plunge. But, much of the thread I’ve had for years is poly or a cotton-poly blend: your interview didn’t go into blends: what do you think? I’ve been doing a lot of reading about quilting – books – and the general concensus seems to be: use cotton thread if you’re quilting with cotton fabric…please clarify: ok to use a cotton/poly blend while sewing quilty with cotton? Thanks!

    • Suzy Quilts says:

      Great question! I consider 100% poly and poly blend threads to be interchangeable when quilting and they are both completely fine for piecing. You could use them for machine quilting, but I think you will find 100% cotton thread to feel softer after a few washes.

  19. Michele Alford says:

    I sew garments, not quilts, and have just switched to cotton thread. The more I read about micro plastics, the less I want to have anything to do with polyester. It is estimated that more than a third of the micro plastics in the ocean are due to the leaching of polyester and other synthetic fibers when laundered. Yikes!!!

  20. Morgan Wood says:

    Fantastic. If teachers everywhere taught like you do, it would be more enjoyable and we’d all be smarter! Thanks for this post. I’m a bit sheepish that a year into quilting… and TONS of YouTube videos on various blocks and techniques… I’m JUST learning about choosing the proper thread and needles. Yikes. Maybe *I’m* not always the problem! Cheers 😉

  21. Georgia says:

    Great article of the ‘Threads’, informative and funny.

    Hey Suz, which can be used to make bowl cozies, cotton or polyester thread, with cotton fabric?

    • Suzy Williams says:

      Thank you 🙂 Since you’re using cotton fabric you could go either way. If you plan on being super dooper tough on them, poly might be the way to go, but honestly a nice 40 or 30 wt. cotton thread would also do just fine.

  22. Bernice says:

    If using bowl cozies in the microwave you have to use 100% cotton thread or they will catch fire if you use polyester thread to sew them with. 👍

  23. Kathy says:

    Of all the articles I have read about the difference between P and C this is the one that I will always reminder. Great job.

  24. Carrie Wikander says:

    In defense of cotton, I bought all these popular and beautiful poly threads that had a beautiful sheen on them and they frayed and broke all the time, no matter what needles I used. I ended up giving them away and going back to all cotton. That’s why I’m on team cotton.

  25. Shae Campos says:

    You are hilarious! This is a great informative article too! You always seem to have the exact tips I need every Tuesday. 🥳

  26. LindaBelle says:

    My Mom (a 30+ yr quilter) noticed that she had to redo multiple bindings on quilts done in poly-thread, but not for cotton thread.

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