How to Identify Fabric Fiber Content with a Fabric Burn Test?
If you find yourself at the very first stages of fabric sourcing, you might have trouble identifying the fibers that make up your fabric. That’s when a fabric burn test can be really useful.
Maybe you bought a garment or found some fabric, and you’d like to source something similar? It’s sometimes possible to find details about fabric content printed on the clothing or fabric label. But what if this isn’t specified?
In this article, you will find out why identifying fabric fiber is important, what the fabric burn test can tell us and how to conduct a burn test in order to identify the fibers that make up your fabric.
Why is identifying fabric fiber important?
1. It Aids Communication With Fabric Suppliers
Understanding fabric fiber or fabric content is essential when you’re communicating with fabric suppliers.
For example, did you know that polyester is quick drying and suitable for almost any kind of printing? Or that nylon is softer than polyester but a bad choice for digital print?
Every fabric composition has its own characteristics. And you’ll save a lot of time with your fabric supplier if you already know what fabric fiber content you’re looking for.
2. Fabric Content Affects Fabric Price
Most things come down to money. We can probably all agree on that. When you know what fiber content you need for your fabric, you’ll get a clearer idea of price range. This will make budgeting much easier.
3. You Know What You’re Getting
When you don’t know how to identify fabric content, unscrupulous fabric suppliers can take advantage of your inexperience. We like to assume that everyone is honest. But it’s always best to err on the side of caution.
What can the burn test tell us?
The primary purpose of the burn test is to determine if the fabric swatch is made of natural or synthetic fibers. The flame, smoke, odor and ash all help us to identify the fabric being burned.
However, there are some limitations to the burn test. We can only identify the fabric fiber when the fiber is 100% pure. If a number of different fibers or yarns are blended together, it is hard to distinguish the individual elements.
In addition, if the fabric swatch has undergone a post-finishing process, this might also affect the test result.
How to Identify Fabric Fiber With the Fabric Burn Test (For Weft Knitted Fabric)?
Before we start, take a moment to check your surroundings.
- Conduct the burn test in a draught-free environment so you can keep the flame under control more easily.
- Make sure you don’t have anything especially flammable close by.
- Some materials, like polyester and nylon, will melt and even drip when they are burned. So please do the test on a fire-resistant surface or use a piece of aluminium foil to protect your table.
- Keep hair and clothes tucked away while you are doing the burn test.
How to Conduct the Burn Test
Before we burn the fabric, we need to prepare it. We don’t recommend that you burn the whole fabric swatch because if there’s more than one kind of fiber contained within it, the results of the burn test won’t be accurate.
So first, we need to extract the fiber or the yarn from the fabric swatch.
1. Cut the fabric swatch into a small 3-4cm square.
2. Pull fibers from the fabric swatch. Separate fibers that look different from one another. Keep pulling the yarn from the fabric swatch until you can twist each set of fibers into a small fiber ball.
3. Use a tweezer to hold one end of the fiber ball. Hold and light a lighter with the other hand. Move the flame slowly towards the fiber to ignite it.
Observe the way the fiber reacts when the flame moves close to it, while it burns and after the flame moves away. Also note the smell of the residue and the residue itself.
Fabric Burn Test Results
Generally, natural fiber is easily flammable. The flame doesn’t sputter. There’s a papery smell after burning. And the ashes are easy to crush.
Synthetic fiber will shrink quickly when the flame approaches. It will melt and burn slowly. There will be an unpleasant smell. And the residue will look and feel like a hard bead.
Cotton ignites and burns quickly. The flame is round, calm and yellow. The smoke is white. After removing the flame, the fiber will continue to burn. The odor is like burning paper. The ash is dark gray and can be crushed into a powder easily.
Rayon ignites and burns quickly. The flame is round, calm and yellow. There is no smoke. After removing the flame, the fiber will continue to burn. The odor is like burning paper. There won’t be a lot of ash. The ash that does remain will be light gray in color.
Acrylic shrinks quickly when the flame approaches. The flame sputters and the smoke is black. After removing the flame, the fiber will continue to burn. The ash is yellow-brown, hard and of an irregular shape.
Polyester shrinks quickly when the flame approaches. It then melts and burns slowly. The smoke is black. After removing the flame, the fiber will not continue to burn. It has a chemical odor, similar to burned plastic. The residue forms into round, hard, melted black beads.
Nylon shrinks quickly when the flame approaches. It then melts and burns slowly. There will be small bubbles when burning. The smoke is black. After removing the flame, the fiber will not continue to burn. It has a celery-like, chemical odor. The residue forms into round, hard, melted black beads.
Actual burn test result
The simple compare chart of burn test results
|Cotton||easily flammable, round flame||white||papery smell||dark gray, can be easily crushed|
|Rayon||easily flammable, round flame||white||papery smell||light gray|
|Acrylic||shrinks quickly, melts and burns slowly||black||chemical smell||yellow-brown, hard, irregular shape|
|Polyester||shrinks quickly, melts and burns slowly||black||chemical smell||round, hard, melted black beads|
|Nylon||shrinks quickly, melts and burns slowly||black||celery-like smell||round, hard, melted black beads|