A fabric burn test can help you discover if a fabric is 100% cotton or made from other fibers. That knowledge is important for quilters who swap fabrics with others, and for anyone who wants to be sure of proper care instructions for their finished quilts and other projects.
But I Always Buy All-Cotton Fabrics
Do you ever buy fabrics on eBay or at estate sales and flea markets? What about your non-quilting friends, do they ever offer to give you excess fabrics? Have you received fabrics in a swap that you're not sure about?
Unless you absolutely recognize fabrics as quilting cottons, there's no way of knowing their fiber content without performing a few tests.
An easy way to help identify fabric content is to perform a fabric burn test. The test helps you determine if a fabric is 100-percent cotton, or something else. Be sure to perform the burn test outside on a day that's not windy, or in a well ventilated area inside, away from flammable items.
Fabric Burn Test Supplies
- The fabric(s) you want to test
- A flameproof container with walls -- try a large ashtray
- Long matches or another source of a small flame
- Long tweezers or a hemostat
Perform the Burn Test
- Cut small swatches of each fabric you want to test. Two-inch squares are fine.
- Place a swatch in your fireproof container and ignite a corner of the fabric.
- Pay attention to the odor of the smoke.
- Cotton smells like burning paper.
- An odor similar to burning hair or feathers indicates wool or silk fibers, but silk doesn't always burn as easily as wool.
- A darkish plume of smoke that smells like chemicals or burning plastic probably means the fabric is a cotton/polyester blend.
- Examine the ashes after they've cooled.
- Cotton ashes are soft and fine. They turn to dust when touched.
- Black, brittle remnants that crush between your fingers indicate wool fibers.
- Hard lumps are the remains of melted synthetic fibers.
- Take one more step. Unravel a clump of threads from another small swatch of the fabric. Hold the clump with tweezers (over your flameproof container) and slowly move a small flame towards the clump.
- Cotton fibers ignite as the flame draws near.
- Synthetic fibers curl away from the heat and tend to melt.
To see exactly how each type of fabric reacts, do experimental burn tests on fabrics you know are made from cotton, cotton/polyester blends, wool and other fibers.
Fabrics Sometimes Mistaken for Cotton
- Linen is similar to cotton but burns more slowly.
- Rayon still burns after the flame is removed, and although it has an odor similar to cotton or paper, it does not have an afterglow after removing it from the flame. Cotton produces an afterglow.
If You Don't Think the Fabric is Cotton
Most of us make the majority of our quilts with 100-percent cotton fabrics, but there's no rule that says you must sew with one type of fabric or another. Go ahead and use a fabric if you like it, but do try to determine what type of fabric it is so that you'll know how to care for the quilt when it's finished.
One bit of advice, most quilt block and fabric swaps do require that you use all-cotton fabrics. Reserve fabrics made from other materials for your own use or for swaps that allow variations.