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.
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!