I Love Shiny Things...

 



My First Brazilian Embroidery

My favorite shiny thing is glossy thread, and the glossiest thread bar none, is rayon. Over the course of my stitching career, I've taken several classes and workshops in Brazilian embroidery. I love the brilliant colors and the way the thread lays but above all I love the glossy shine over the finished project. When I was new to Brazilian embroidery, it felt unique to me, not because the stitches were different, but because every thread used is rayon. Threads come in varying weights; from very fine to very heavy. All traditional stitches and techniques are the same only the thread, and how you treat it, are different.

The big difference I found is how rayon thread should be prepped before stitching. The first thing that's required, once you've gathered up your supplies, is to get "rid of" or "tame" the hard-to-remove memory. All viscose threads have a built-in "memory" and it's stubborn. The curling and twisting is quite visible the minute you take it out of the package. So, what do you do to get that thread to untwist?  Steam. Steam is the easiest and quickest way to straighten the thread without getting it "wet" and that's nice because you can stitch right after straightening without having to wait for the thread to dry [another way to straighten rayon thread is to dampen it]. Boil the water and as soon as the kettle or pot is hot enough and the steam begins to billow up, the pot is ready to straighten the thread. Simply take out and unwind the skein of thread as you pass it through the steam. Amazingly, the thread begins to unwind and become straight. Don't rewind it, just loosely gather it up in a neatened circle while you stitch.  If it starts to curl back up, simply pass it through the steam again and voila, problem is solved. The other necessity when using rayon threads is making sure that you split the thread with your needle when ending your stitching, as you take your thread to the back. On the back of your work, it's a good practice to use a teeny, tiny bit of of Fray Check on the thread tails [and the tails only] when tying off. Make sure not to get any of the Fray Check on your foundation fabric. It doesn't come out and it will age with a yellowish tinge.

Now, that being said, I have quite a few friends that have also taken a fancy to rayon thread and have begun using it in their smocking and heirloom sewing, either by hand or machine embroidery. My caution is this: although rayon begins as a natural cellulose product from wood, the processes required in order to develop it into a fiber are caustic and not conducive to the whole idea of heirloom sewing, which is to create garments that can and will be passed from generation to generation looking as if they were just made. If you are going to create an embroidered piece to frame and then hang, this fiber is wonderful and suitable for that, but, it is not suitable, in my opinion, for heirloom sewing. There are so many chemicals used to break down and create rayon thread that at the end of the process it doesn't resemble anything "natural". Processed wood cellulose has been treated or bathed in lignin, caustic soda, carbon disulfide and sulfuric acid. If you're protective of your scrap booking and refuse to use products containing lignin because you know what it will do to your photos, can you imagine what lignin, not to mention residual sulfuric acid, will do to your cotton heirlooms? Exactly. No matter how much I love this thread, I will not use it in my heirloom sewing and especially not in my smocking. Just one gal's opinion.

Below is a mini-education on how wood cellulose is processed to produce rayon thread.

Regular rayon (or viscose) is the most widely produced form of rayon. This method of rayon production has been utilized since the early 1900s and it has the ability to produce either filament or staple fibers. The process is as follows:

1. Cellulose: Production begins with processed cellulose
2. Immersion: The cellulose is dissolved in caustic soda: (C₆H₁₀O₅)_n + nNaOH → (C₆H₉O₄ONa)_n + nH₂O
3. Pressing: The solution is then pressed between rollers to remove excess liquid
4. White Crumb: The pressed sheets are crumbled or shredded to produce what is known as "white crumb"
5. Aging: The "white crumb" is aged through exposure to oxygen
6. Xanthation: The aged "white crumb" is mixed with carbon disulfide in a process known as Xanthation, the aged alkali cellulose crumbs are placed in vats and are allowed to react with carbon disulfide under controlled temperature (20 to 30 °C) to form cellulose xanthate: (C₆H₉O₄ONa)_n + nCS₂ → (C₆H₉O₄O-SC-SNa)_n
7. Yellow Crumb: Xanthation changes the chemical makeup of the cellulose mixture and the resulting product is now called "yellow crumb"
8. Viscose: The "yellow crumb" is dissolved in a caustic solution to form viscose
9. Ripening: The viscose is set to stand for a period of time, allowing it to ripen: (C₆H₉O₄O-SC-SNa)_n + nH₂O → (C₆H₁₀O₅)_n + nCS₂ + nNaOH
10. Filtering: After ripening, the viscose is filtered to remove any undissolved particles
11. Degassing: Any bubbles of air are pressed from the viscose in a degassing process
12. Extruding: The viscose solution is extruded through a spinneret, which resembles a shower head with many small holes
13. Acid Bath: As the viscose exits the spinneret, it lands in a bath of sulfuric acid, resulting in the formation of rayon filaments: (C₆H₉O₄O-SC-SNa)_n + ½nH₂SO₄ → (C₆H₁₀O₅)_n + nCS₂ + ½nNa₂SO₄
14. Drawing: The rayon filaments are stretched, known as drawing, to straighten out the fibers
15. Washing: The fibers are then washed to remove any residual chemicals
16. Cutting: If filament fibers are desired the process ends here. The filaments are cut down when producing staple fibers^[1]

High wet modulus rayon (HWM) is a modified version of viscose that has a greater strength when wet. It also has the ability to be mercerized like cotton. HWM rayons are also known as "polynosic"^{[clarification needed]} or can be identified by the trade name Modal.^[9]

High-tenacity rayon is another modified version of viscose that has almost twice the strength of HWM. This type of rayon is typically used for industrial purposes such as tire cord.^[9]

Cupramonium rayon has properties similar to viscose but during production, the cellulose is combined with copper and ammonia (Schweizer's reagent). Due to the environmental effects of this production method, cupramonium rayon is no longer produced in the United States.^[9]