Can anyone tell me how to tell if thread is polyester or rayon? I recently found some Robison Anton King spools at our local thrift store. They were a great price and still in original sealed wrappers. I have gone to the RA site to check colours but that was not helpful. I am thinking that these were discontinued..... The trouble is the tag does not specify rayon or polyester. Any ideas will be much appreciated.

After a while, you may be able to tell the difference by look. However, the newer poly threads are beginning to give the same shine as rayon. So, if I think I won't be able to tell by sight, I use a Sharpie to write P or R inside the bottom of the cone.

The burn test works well for fabrics too. If you get melted beads and ashes, you have a cotton/poly blend. Wool will disolve in chrorine bleach. So, if you want to know if something is poly or wool, put a piece in some bleach and see if it dissolves.

1 comment

by chenille 28 Jul 2018

Now that is good to know, thanks!

Regardless , I love RA thread. Buy it and be happy. Kay

1 comment

by chenille 28 Jul 2018

Oh I did! I took all they had....8 5500yd. king cones, 4 different colours! Doing the happy dance!!

Burn test is definitive. The fact that they were still in wrappers may just mean they came from someone's estate. P.S. Numbers run differently for RA rayon and RA polyester, too.

1 comment

by chenille 27 Jul 2018

Thanks!

.Polyester thread will melt while rayon thread will burn...
Here is a video on using the burn test to help determine what the make up of threads/fabrics are...Polyester thread will melt while rayon thread will burn...

https://www.youtube.com/watch?v=k...

1 comment

by chenille 27 Jul 2018

Super video, thanks!