Playing favorites is frowned upon in parenting and politics. But when it comes to embroidery, it is nearly impossible to speak with an experienced embroiderer who does not reach for their favorite general purpose embroidery thread—either made up of rayon or polyester—on a daily basis. Sure, there are colors, both personal choices and those requested by clients, that may dictate the cone you reach for, but those embroiderers who do not understand the inherent differences in rayon and polyester embroidery threads may be reaching for the wrong thread without knowing why.
There are similarities between rayon and polyester, which sometimes makes the choice tougher. Both of these all-purpose embroidery threads are 40-weight, which means that 99 percent of all stock designs you will find anywhere will run well and produce the design you are after. Both would be stitched using a 75/11 needle. Both are available in small put-ups of 1,100 yards, and large put-ups of 5,500 yards. Both rayon and polyester are available in more than 400 colors from top thread manufacturers. Both are matched to Pantone colors for accuracy in color matching. Both are designed for running at high speeds on commercial embroidery machines. Both reflect light, bringing a shine to the embroidered design. When purchased from a responsible manufacturer, both are Oeko-Tex certified to be free of harmful substances, making them safe for use on all apparel, including children’s and infant wear.
Even with these similarities, your end product should dictate which of these 40-weight threads you choose.
If your embroidery shop produces much work on uniforms, commercial linens, work wear, or children’s clothing—any items that may be tossed into heavy duty wash water when laundering—polyester embroidery thread should be your choice. Most 100 percent polyester embroidery threads are resistant to chlorine bleach that is used in commercial laundering. Even bathing suits, which are subjected to chlorine in pool water, will hold their color best when embroidered with polyester thread.
A good quality rayon thread can withstand high temperatures of wash water; from 140 degrees F for a normal household wash to 203 degrees F for heavily soiled items, as long as detergents contain no bleaching agents, peroxide, or optical brighteners. But if there is any chance that your customer is apt to use bleach, or sell to someone who does, you will be safe by embroidering with a good quality polyester thread.
The popularity of the worn look of denim would also dictate polyester for embellishment, since polyester embroidery thread is safe for stone washing. This process—which not only breaks down the fibers with large stones, but also the color with added bleach—results in the worn, soft and comfortable look that we associate with jeans.
When it comes to versatility, and the ability to problem solve, both rayon and polyester offer enough choices to border on confusion. Here again, both offer weights that make it possible to produce extremely small details and lettering. Finer 60-weight thread is a problem solver when it comes to including incredible detail, shading, or small readable letters in badges and logos, and it is available in both rayon and polyester. It is also a good choice when embroidering on fine, delicate fabrics. Think through to your end product when deciding between the two.
Beyond its 60-weight for small embroidery, rayon is also available in a 30-weight, which helps improve the time and cost of producing embroidered items with lots of fill. Since it is thicker, the 30-weight requires less density, and therefore less stitches and less thread, to fill up space in a design. Commercial embroiderers who run multiple machine heads often turn to this thicker thread for some cost cutting, since it will require some 20 percent less thread to complete.
Rayon is also available in a very thick 12-weight for decorative stitches and embroidering on heavyweight fabrics. For incredibly small detail, there is a polyester on the market that is a 75-weight. Fairly new to the industry, this super fine thread is also used for fine filigree work and to attach sequins.
Also on the market is a 100 percent polyester matte finish polyester thread which is highly colorfast in commercial laundering and when exposed to sunlight for prolonged lengths of time. The matte finish is appealing to quilters, who like the soft look of cotton combined with the strength and durability of polyester. Also, for tone-on-tone, or where a subtle appearance is desired, a matte finish polyester is a good choice.
Ease of operation
Although you will hear embroiderers tell you that polyester is the stronger of the two threads, the runnability of both is going to come down to your machine and your knowledge of running it. Polyester’s low elongation is said to eliminate looping and puckering. The lower the elongation of the thread, the less critical the timing and the more accurate each stitch.
Rayon’s tensile strength is known worldwide, making it the choice of international designers. Considered the most flexible of embroidery threads due to its softness and pliability, rayon can be stitched out in any direction and will lie flat in the most intricate of designs. It too, will run flawlessly and without thread breaks when a good quality thread is chosen.
Less abrasive than polyester thread, rayon is softer against skin and gentle on the working parts of your embroidery machine.
Effect on machines
Considering that your most costly expense is likely the embroidery machines that will run the thread, what kind of effect will each have on your equipment? For that answer, we turned to technician Bill Garvin, the president of his own BG Tech Services in Tampa, Fla. who is often invited to share his knowledge at trade shows and in trade publications.
“As far as wear and tear on a machine, as a technician I do not see more or less damage from polyester verses rayon thread. However, the poly will wear a needle a little faster than rayon. Keep in mind that it is never the tip of a needle that wears out, it’s always the eye. Either thread will eventually cut a groove in the top of the eye, causing the thread to not just break, but fray and bunch up on itself. As a rule of thumb, I usually suggest to my clients that during normal production, after the second thread break, change the needle. And keep in mind that common colors, such as white, black, red. will wear out faster.
As a synthetic material, polyester will stretch before it will break. Because of its elasticity, it will need a firmer tension than rayon on almost all machines. However, if you have properly set tensions on your machine, you should not have to adjust, going from one thread to the other. And keep in mind, about 85 percent of all tension issues are the result of a poorly maintained bobbin case.
Finally, there is an area where rayon will perform better than polyester ever can: dog collars, horse bridles, heavy fabrics, and satin or oxford style jackets. Those weaves are so tight and heavy that the polyester will catch on it at both entry and exit. When most people see the looping they will tighten the tensions on the machine to try and fix it, to counter act the stretch of the thread. My advice? Use rayon. No looping!
While personal preference will come into play with some thread choices, always be sure to let your substrate be the ultimate decision maker. While the appearance won’t be drastically different in most cases, the path to getting to your finished result will either be easy or fraught with breaks, headaches, and time spent cursing your thread. Use the chart below to help compare what thread works best for you.