Determining Fiber Content
by Jean Lotz
Many times I find an old piece of fabric that looks promising. I try to use natural fabrics for my dolls, and so I need to be able to determine what the fiber content is.
I was told that some older sewing books dealt with this issue and it might be wise to check in the basic information sections of Vogue, Singer and a few other how-to sewing books.
Many years ago a dear lady, the manager of a local fine fabric store, showed me how to determine fabric content by burning a small swatch of the fabric. By studying the rate it burns, the color of the flame, the smell of the smoke and the structure of the burned cloth, some people can even guess the content and relative percentage of natural versus man-made materials used in a fabric.
I built a small library of burned fabric samples. Some from known fabric and others from mystery material. I burn only the corner from a small 2" square swatch. I kept notes on how the burned area felt by touch, the rate of burn and the burning smell. Now I can compare burned out mystery swatches to my known fiber content burn samples. For example: if I want to check if a piece of material is truly silk, I burn a corner of a small swatch and compare it to my known sample of burned silk.
To keep all of these burned fabric samples neat and readily available, I store them in a set of 8x10 plastic slide storage sheets. The slide windows are the perfect size to hold each burned swatch along with any notes that I made on a small piece of paper. Don't I sound so efficient? I also keep track of the material that I have in storage by keeping a swatch of each piece of material and its fiber content in another set of these slide holders. Of course then I have to try to find the corresponding larger piece of material - wish me luck! This is where my efficiency ends!
Fabric Burning and Testing Method:
I take a 2" square piece of my fabric and burn a corner. I always burn swatches near a sink so I can stop the flames quickly if they are out of control.
Results to look for:
- Cotton burns quickly and the scorched area stays smooth.
- Cotton/polyester burns relatively fast and the scorched area is lumpy and bumpy. You can get to the point of telling the approximate percentage of polyester in it by the amount the fabric curls and melts rather than burns.
- Silk burns quickly and smells funny like burning hair to me.
- Wool also stinks when it burns.
- Linen burns with a particular smell and the weave is still obvious.
I asked a friend, Kenneth Loyal Smith (a professional textile conservator), for more information on determining fiber content and he adds:
- In the textile field the term "bast" means any fiber from a plant source. Linen, abba, pina, ramey, etc. are all bast while "protein" fibers are all from animals: silk, wool, human hair, etc.
- Hair/silk/wool are protein fibers and all smell the same when burned.
- Another test for linen is to put it in water and see if the fibers swell quickly. Since linen is a "bast" or vegetable fiber, they swell a lot, especially when older. Also, linen has always been difficult to dye. If the fabric has been dyed, it is most likely cotton. If it was printed on, again it was most likely cotton.
- There are some wonderful older reference books - out of print textile books. The ones dated prior to 1920 and after 1870 deal with all the "newly invented" synthetic fibers and dyes. Yes, there were synthetics then. Rayon was one.