Testing dennim to see if 100% cotten

[ike]

I have 10yds of this fabric it .008 thick. The label on the purchase ticket says denim. I have read on some posts that you can burn a small part of it and the results will tell me if it is 100% cotton. Please direct me to or tell me what I should look for when a small piece is burned. Thanks

 

[coloradoclyde]

If you burn or char the material, no part of the remains should be hard or crusty....it also should not curl up when heated....These are signs of synthetic materials.
Turning it into char cloth for fire starting is actually a very good indicator of quality, as synthetic fiber will not take a spark from a flint.

Dismantling the fabric into it's individual warp and weft fibers and then burning them individually, will also indicate synthetic fibers.... if they curl, melt, etc....they are synthetic.

 

[ike]

Thanks so much for the help. I burned a piece before I posted the question and it burned with very little residue and did not curl.

 

[coloradoclyde]

I would also add that I have used cotton "denim" with a small percentage of synthetic fibers without any problem......That said, every situation is unique....

Do a test firing and check you fired patches...