How to Check Fabric Composition?
A fabric’s fiber composition is the percentage by weight of each fiber making up that fabric.
If you have a fabric swatch in hand with an unknown fiber composition, it will be nigh impossible to order more fabric of the same type. Where would you even start with a google search? After reading this article, you will no longer need to rely on your fabric supplier to check the fiber composition for you. In this article, you will learn the following:
- Why is a fabric’s fiber composition so important?
- How to check the fiber composition of knitted fabrics.
When is it important to know a fabric’s fiber composition?
1. When sourcing fabric
A fabric’s fiber composition is the very first thing that you should know to start sourcing fabric. Your fabric supplier will be able to acquire a more accurate match to your desired fabric, if you can tell them the fabric’s fiber composition.
2. When you want to double check the composition of the fabric you ordered
You want what you’ve paid. We assume that everyone is honest, but you never know, and you want your customer to receive what they’ve paid for as well.
3. A fabric’s fiber composition is essential for labeling
If you are importing or exporting fabrics or garments, then the tariffs on those imports and exports is greatly affected by the fiber composition. Furthermore, most countries require a fiber composition label to be attached to all finished products.
How to check the fabric composition of knitted fabrics?
Please prepare the following tools:
- A scissors
- A precision digital scale
- A pen
- A piece of paper for note-taking.
1. Cut a small piece off of the fabric swatch
We only need a small piece of fabric for the test. Occasionally, the fabric is quite expensive, so we only take what we need from the swatch. Cut a square from the swatch that is about 3-4 cm on one side, if the swatch is already quite small, then there is no need to cut it!
2. Pull the fiber from the square piece
Orient the fabric square vertically. (The knitting pattern should appear to have vertical lines) Then pull some yarn from the edge. Keep pulling the yarn until you get the full length of one yarn, from one side to another. It may take some time. Be patient.
3. Separate the yarns into different piles
Separate the yarns that look or feel different to you in different piles. Remember which type of yarn was the last to be pulled from the fabric, then try to get at least 10 of each type of yarn and the very last yarn you pull out should be of the same type that came last initially. This is to allow you to get an accurate representation of the fabric’s fiber composition.
4. Weigh each pile of yarn
Put the piles of each type of yarn on the scale and write down the weights.
5. Do the math
Add up the total weight of all the yarns. Then use the following formula to calculate the fiber composition percentages:
(The weight of one yarn pile ÷ the total weight of all the yarns) x 100% = Fiber percentage
In this case, the total weight of the black yarn pile and the grey yarn pile is 0.035g + 0.045g = 0.08g.
The fiber composition percentage of the black yarn pile will be (0.035 ÷ 0.08) x 100% = 43.75%
The fiber composition percentage of the grey yarn pile will be (0.045 ÷ 0.08) x 100% = 56.25%
6. Identify yarn material
You can perform a simple burn test to identify the material makeup of the yarns. We have an article that explains how to conduct a burn test: how to identify fabric fiber content by burn test.
- If your fabric swatch is stretchy, it might contain spandex (elastane). Sometimes it is difficult to pull spandex yarns from the fabric. Other types of yarn can also get stuck by the spandex. It will take some time to get the full length of a spandex yarn. If the spandex yarn cannot be entirely pulled out, the result will not be accurate. In this case, we suggest you send us the fabric so we can analyze it for you.
- Please note that it is normal for the final result to be slightly different than the percentages shown on the label.