Mary Corbet

writer and founder


I learned to embroider when I was a kid, when everyone was really into cross stitch (remember the '80s?). Eventually, I migrated to surface embroidery, teaching myself with whatever I could get my hands on...read more

Contact Mary

Connect with Mary



2024 (62) 2023 (125) 2022 (136) 2021 (130) 2020 (132) 2019 (147) 2018 (146) 2017 (169) 2016 (147) 2015 (246) 2014 (294) 2013 (294) 2012 (305) 2011 (306) 2010 (316) 2009 (367) 2008 (352) 2007 (225) 2006 (139)

Fire & Thread: What’s a Burn Test?


Amazon Books

Have you ever come across a stray piece of fabric or an labeled skein or spool of thread and wondered what type of fabric or thread it was?

Sometimes, you can know just by looking. But sometimes you can’t. Especially if blends are involved, discerning a type of thread or fabric can be tricky.

To help me figure out what an unlabeled or thread might be made of, I usually resort to a burn test. A burn test involves igniting fibers to see how they burn and behave. This is something you can do at home with a few simply tools.

The more you burn test different fibers, the more you’ll get a better notion of what to look for in the burn, the ash, and the smell, to help you discern particular fiber content.

Burn test for threads and fabric

To do a burn test, it’s helpful to have a few things on hand: a small candle (tea light size works well), matches or a lighter, some tweezers, and a heat-resistant / burn resistant tray or plate. I used a spare lid of a metal tin for the burn test I did last week, but I find that the best foundation to do these things on are usually the glass candle plates used for pillar candles. They work great for burn tests, especially if you have a large one.

Besides the unlabeled pieces that you’re testing, it’s helpful to have on hand some labeled threads or fabrics that you’re certain of, as far as their fiber content is concerned.

For example, if one of your unlabeled pieces looks like linen, have a small piece of certain linen on hand so you can compare your burns. Or if you think you have a poly-cotton blend, have some polyester on hand (polyester thread is fine) and some cotton on hand.

To do a burn test on fabric, you can always test a small cut of the fabric, or you can remove some threads from the warp and the weft of the fabric. If you’re working with a blend especially, you’ll want to test both warp and weft threads in the fabric.

I like to remove threads from the fabric and test the threads. I remove enough to create a small bundle, and spread out the bundle a little, and light it.

Linen ignites fairly quickly and it burns. It ignites much like a candle wick and it burns to a soft gray ash. It has a lingering afterglow. It smells like paper or wood. When you touch the ash, it’s very soft and it dissolves into an ashy smear on your fingers.

Cotton is much like linen. I think it tends to ignite a little more quickly, the afterglow doesn’t linger as long, and it burns into a dark (black) ash that strikes me as not-as-soft as linen ash. It also smells like burning paper or wood.

Silk and wool both stink like burning hair. As you take them towards the flame, they tends to pull away or curl away from it. They both tend to go out pretty quickly. Silk resolves into a bead of ash that you can crush pretty easily. Wool resolves into a dark ash that’s charcoaly.

Polyester, nylon, and acrylic all ignite really quickly and melt. They melt into a hard bead. They don’t smell like wood or paper, and they don’t smell like hair. Mostly, they smell like chemicals or plastic. They don’t stay lit.

Chances are, you’ve probably come across unlabeled fabrics or threads before, and wondered what they were. Now you know a good way to help you discern fiber content! You can definitely google the topic of fabric burn tests and find all kinds of thorough information out there, I’m sure. As with most things, the more you familiarize yourself with the process and results, the more easily you’ll be able to quickly discern the content of your fibers.

Of course, be careful when you’re playing with fire! Use tweezers to hold your fibers (especially synthetics – they can ignite quickly and they can stick on you), and make sure you have a work space with a non-flammable surface to place things on.

I hope this information comes in handy for you!

Happy Monday!


Leave A Comment

Your email address will not be published. Required fields are marked *


(8) Comments

  1. Thanks Mary, very clear and informative! Burn testing is fun (pyromaniacal giggle :), but one other thing I think is worth mentioning is that it’s important to have good ventilation and extinguish your burns pretty quickly.

    Many synthetics when burned give off fumes that are toxic, and while a quick whiff of burning fiber for a couple of seconds is unlikely to hurt most people, it’s good to minimize the risk by having lots of fresh air in circulation.

  2. Your timing is perfect! I have been going through all my crafting things as part of my January de-stash/clean up and had come across some unlabeled fabric. I’d meant to google how to identify it later today and you saved me the trouble =). Thank you!

  3. Mary – Thank you so much for this! It’s incredibly useful information for thread and fabric. The only question I would ask is how is rayon in terms of burning? It is made of plant pulp/fiber but I think there’s a lot of processing to get it to either embroidery thread or fabric. Then there’s the question of blends but I think those could be guessed at. No worries about the rayon. I’m going to both google it and try it as I have both thread and fabric that I know are rayon. Thanks again for a great post.

  4. I sometimes do the burn test when dealing with fabrics for quilting. I tend to have a bowl of water that I drop the burning fabric into, to put it out quicker. I once had a poly fabric flick around and land on my skin. Still have the scar.

  5. Thank you for posting this.

    Husband and I are 18th century reenactors. One of the first things one learns about buying/making reproduction clothing is that it has to be a “natural” fabric – cotton, linen, wool, silk – NO polyester, acrylic or other “plastic” fabric.

    At first husband and I thought this a bit picky until we found out why. As a reenactor one is around fire a good deal of the time – whether cooking over the campfire, firing a black powder gun (musket, rifle, cannon), or working around candles/lanterns at night – fire is always something one has to be careful about – then and now.

    When making the clothing one has to use the natural fabrics as when they burn – while maybe quickly – they burn to an ash. Modern “plastic” fabrics – polyester and such will melt instead of burning to ash. While we, of course, look to have no accidents a burn from natural fabric is better than one from a plastic fabric.

    Luckily our unit has not had fire accidents other than an occasional mild finger burn while firing a gun, etc in the 30 or so years we have been members. We do a Christmas season indoor event during which I stand in front of a huge open fireplace of the time in my long petticoat (skirt) and jacket and we have candles lit all over the house and have never even had a close call to any of us catching fire. I also have substituted in a number of times firing the cannon and also have not had any accidents. Burns are fairly rare, luckily for the unit as a whole as we constantly remind members to be careful and supervise new members – and children – very carefully.

  6. Thank you for that detailed information. When I was young and pressing cotton, especially if I was fuseing interfacing for a sewing project, I thought the cotton fabric smelled like popcorn.

  7. I love a reason to burn things 🙂 I’ve done burn tests on fabric for quilting, but hadn’t thought about it for thread. Thanks!

  8. The burning/melting of polyester is actually used a lot in modern kanzashi. A lot of crafters melt the cut ribbons to prevent frays and quickly glue the edges rather than sew and whipstitch.
    After a couple projects, I can’t stand the smell and now feel ill whenever I get a whiff of burnt polyester. Give me fray stopper liquid and a needle and thread any day!

More Comments