Recently I was commissioned to turn a wrap skirt into a pillow cover. My customer advised that the wrap skirt was given to her as a gift from Thailand and that it might be silk but she wasn't sure about it. Once I was done with sewing her the pillow, I had some left over scraps and decided to do a burn test. A burn test is the most common and well-known test conducted by factories and home-sewer to identify one fabric from the other.
Along with the supposed silk fabric strip, I cut out some more: crepe, wool, rayon, cotton and linen.
Crepe is a twisted weave fabric with a pebbly appearance that doesn’t wrinkle or crease easily. While wool and polyester crepes are the most common, silk, rayon and occasionally cotton crepes are also available. This fabric can be very flattering on the body and is suitable for tailored trousers, straight skirts, jackets, full skirts or semi-fitted dresses.
As a hobby seamstress, I think it is important to know what you are working with. Only then, you can pick the right pattern for your fabric, choose the right needle, use the right temperature on your iron and know how to treat it.
If ever you wish to try out a burn test, please do this outside and keep a bucket of water close by. Be mindful that we are dealing with an open flame and be careful! To conduct a burn test yourself, you would require:
the respective fabric
a flame-proof container like ash-tray or BBQ grate and a metal container like a bucket or sink where the water can be quite handy
If you cannot use your sink, a non-plastic pitcher or bucket
Matches or another source of flame
Cut a strip of fabric, I cut mine about 2-3" wide and 6-7" long. Carefully place the piece of fabric over the fireproof container while igniting one of the edges.
While it burns, pay attention to the flame, the odor and the ash colour. Here are some findings when I burnt my fabric stripes:
Polyester (Crepe) Fabric Burn Test
Flame: orange with black smoke and drips.
Behaviour: The fabric melts rather than burns.
Odor: smells like plastic
Residue: hard black coloured bubbles/beads which won't crush. The ash is hard once cooled.
Other noticeable remarks: fuses and shrink away from flame, when pulled of the surface, gooe-like texture.
Then I burnt the supposed silk and it reacted exactly the same way as the crepe which meant that it wasn't genuine silk. Keep reading for more behaviour of silk under flame. Next up wool.
Wool Fabric Burn Test
Flame: burns slow with small flickering flame, sizzles and smoulders. When flame is taken away, no real flame remains.
Odor: smell of burning hair
Residue: Grey-Blackish light Ash that crushes easily
Rayon Fabric Burn Test
Flame: Light Orange flames, burns evenly, no smoke, burns quickly without afterglow
Odor: smell of burning leaves or paper
Residue: Black feather-light ash
Other noticeable remarks: burns like paper
Linen Fabric Burn Test
Flame: Light Orange flames, burns slower than Rayon
Odor: light smell of paper and grass
Residue: very little feathery grey ash