Ask a room full of quilters whether polyester thread belongs in a quilt, and you’ll start a friendly argument. Some won’t touch anything but cotton. Others reach for polyester every day without a second thought. So who’s right?

The short answer: no, good polyester thread isn’t bad for your quilts — but the myth comes from a real place, and there are still times cotton makes more sense. Let’s clear it all up.

Where the myth comes from

The “polyester will ruin your quilt” idea isn’t made up out of nowhere. Decades ago, a lot of polyester thread was coarse, stiff, and far stronger than the fabric around it. The worry was that over years of washing and handling, a rough, overly strong thread could abrade — or even “cut” — the softer cotton fibers it was sewn through.

That concern made sense for the threads of that era. The problem is that the reputation stuck, long after the thread itself changed.

What modern polyester thread is actually like

Today’s quality polyester is a different animal. A thread like Aerofil - Madeira's Polyester thread is core-spun — a strong polyester core wrapped in a smooth outer layer — which makes it fine, smooth, and gentle to sew with, not the stiff, abrasive thread of the past. It behaves beautifully in the machine and sits softly in the seam.

Here’s what good modern polyester actually brings to a quilt:

• Strength without harshness — tough enough to resist breakage, but fine and smooth, so it isn’t sawing away at your fabric.
• Low lint — keeps your machine and bobbin area cleaner than many cotton threads.
• Colorfast and durable — holds its color through washing and won’t weaken the way people fear.
• A subtle sheen and huge color range — great for stitching that you want to catch the light.

In normal quilting use, a fine, quality polyester thread is simply not going to destroy your fabric. That fear belongs to the thread of fifty years ago.

When cotton still makes sense

Being fair: this isn’t “polyester always wins.” Cotton is still a wonderful, often preferable choice, and here’s when we’d reach for it:

• Heirloom and show quilts, where many quilters like matching a natural fiber to natural fabric.
• That soft, matte, traditional look cotton gives (our Cotona- Madeira's Cotton thread line lives here).
• Personal preference — if cotton-on-cotton is your philosophy, that’s completely valid.

Thread choice is a tool decision, not a moral one. The “rule” isn’t never polyester — it’s the right thread for the project.

Where polyester is the better pick

And there are projects where polyester genuinely outperforms cotton:

• High-stress seams — bags, totes, and anything that gets yanked, stuffed, and hauled around.
• Garments — seam construction that needs to flex and hold up to wear and washing.
• Kids’ and everyday quilts — the ones that get loved hard and washed constantly.
• Any project where you want strength and low lint over a matte cotton finish.

The bottom line

Polyester thread isn’t bad for quilts — old, cheap polyester earned a bad reputation that a smooth, modern, core-spun thread like Aerofil simply doesn’t deserve. Choose cotton when you want that traditional, matte, natural-fiber feel, and reach for polyester when you want strength, durability, and low lint. Both belong in a well-stocked thread drawer.

Shop Aerofil polyester thread →

Shop Cotona cotton thread →

A quick FAQ

Will polyester thread cut my cotton fabric?
Not with a fine, quality modern thread. The “cutting” fear comes from old, coarse polyester; smooth core-spun thread like Aerofil sits gently in the seam.

Is polyester thread strong enough for quilts?
More than enough — in fact, its strength is a plus for high-stress and everyday quilts that get washed often.

Does polyester thread fade or weaken over time?
Quality polyester is colorfast and durable; it holds up to repeated washing without breaking down.

So should I use cotton or polyester?
Match the thread to the project: cotton for a soft, traditional, matte finish; polyester for strength, durability, and low lint. Neither is “wrong.”