101: The Burn Test

What to do when you’ve forgotten what fibre that fabric hidden away in your stash since goodness knows when is made of?

Or maybe you bought  an unidentified remnant off the markdown table. 

Perhaps you’re like me, and don’t trust your source. (I’m looking at you, Fashion Fabrics Club)

The best way to test what fibre makes up your mystery fabric is to do a burn test. By the way – this is what’s called a a ‘destructive test’ – you’ll have to sacrifice a small square of your fabric to get the answer you require. Nothing burned, nothing gained.

Silk is actually a protein, and smells a bit like burning hair when put to the flame. It burns very quickly, but the slightest touch of a breeze and the flame is put out. I wasn’t quick enough to get a photo of this burning, but burnt silk hardens and leaves black beads that crush very easily between your fingers: 

Also a protein based fibre, it should smell similar to burning silk. When put to the flame, it will take a little while to catch alight, the flame burns small (you can just see it below) and like silk, is self extinguishing too. The burnt part stays connected to the piece, but can be broken off and crushed.

From the plant fibre family, cotton will catch alight quick smart with a yellow flame, smelling like burning paper and having an afterglow when you take the flame away. I wasn’t quite quick enough to get this all in the frame, but you get the idea. The singed but not burnt cotton fragments will be browned, a bit like toast thats been overcooked, whilst the ash will look soft, fluttery and disintegrate on touch. Heavier weighted cotton like the blue fabric piece singe more and produce less fluttery ash:

Also from the plant fibre family (the flax plant), linen burns slooowly with a yellow flame similarly to cotton but which is slower on the uptake. Definitely the easiest burning specimen to photograph. The dead give away? The burnt fibres will keep their woven shape:

These are easy to spot – synthetics are effectively plastic in a fibrous form, so when put near heat they will shrink away from it, melt, bubble or drip. Have you ever seen a plastic bag near a flame before? It’s pretty similar. 

Being a natural fibre aficionado myself, I’ve burnt my way through my stash trying to find something that is 100% synthetic and visually represents this. But everything synthetic I have is a blend and predominantly natural fibre, so goes up in flames in the same fashion as the main fibre, but burns a LOT faster and the residue is a lot harder, more bead like.

The most distinguishing factor was the smell – acrid.

Perhaps at some point in the future when I purchase a fabric that does this well, I’ll do an update. 

I hope this was as useful to you as it was fun making it :)



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