My main work consists of baby clothing and such and I’ve been told to use polyester threads because the color won’t bleed. Being relatively new to embroidery, I bought a tonne of stuff that are maybe not to useful for my niche like dozens and dozens of rayon threads! (At least I thought they were useless) Not wanting to waste all those beautiful rayon threads, yesterday I did an experiment. I embroidered vertical bars all different colors and all rayon threads on a white cloth and then laundered it several times. The result? no bleeding! Hmmm so how come I keep getting told rayon threads bleed!?
Rayon threads today are much different than they were in the past. Rayon did used to bleed believe or not, especially the cheap brands which I will not mention. The ones I experienced bleeding were essentially the dark colored ones like red and burgundy. Now, I have never experienced a single rayon thread bleed.
The improvement I guess is due to advancement in technology and different processes. However there are still advantages and disadvantages between polyester and rayon. When colorfastness is a concern, polyester thread should be used. For example, use polyester for work uniforms, baby bibs and other items that will be washed more than regularly in hot water with harsh detergent. Although rayon threads today do not bleed when washed normally with detergent, rayon does fade over time. Also, rayon should not be bleached! Take the fabric you’re experimenting with and wash it again, but this time add bleach. You’ll find out why people recommend polyester thread to you for baby clothing. You see, polyester can withstand bleach no problem, and as you know, baby clothing are often washed and bleached. Rayon can’t handle bleach at all.