Wet-Finishing 101: Detergents
As weavers, we all know wet-finishing is a vital and important part of the weaving process. During wet-finishing, fibers move around, “bloom,” and in the case of wools, they can also felt or full. To get the best outcome for your cloth, you need to make sure the water temperature, agitation level, and soap or detergent are the best for your fabric—but how do you know?
First off, you’ll know exactly what to do if you take Laura Fry’s amazing course Wet-Finishing for Weavers. Laura literally wrote the book on wet-finishing handwovens and is considered the foremost expert on wet-finishing in the world (kind of a niche title but still very impressive). In the meantime, though, I thought it would be helpful to define some of the most common detergents you’ll see recommended in Handwoven and for other textile projects.
1. Synthrapol and Professional Textile Detergent:
Synthrapol has been around for years, and the Professional Textile Detergent (PTD) is a newer product made by Dharma Trading Company. While there are some differences in chemical makeup, the two can be used interchangeably. These detergents are designed to efficiently remove excess dye from fabric as well as to keep that dye from settling back into the fabric and, say, staining a white yarn blue. (You will find the PTD in our Finishing Kit for Weavers.)
2. Orvus WA Paste:
Typically referred to simply as Orvus Paste, this is often the detergent of choice listed for silk projects, but it can be used on almost any fiber. It’s also the detergent recommended most often by conservators and other people who work with historical textiles. Originally designed as a horse shampoo, it can usually be found at farm supply and feed stores, usually in very large quantities.
3. No-rinse washes:
There are several brands out there with no-rinse products—the most well-known are Eucalan and Soak—as well as many tutorials on how to make your own if you’re so inclined. True to their name, these washes allow you to wash or wet-finish a fabric without having to rinse any excess detergent out afterwards. You simply add the appropriate amount of product to water and let the fabric soak in it for a specific amount of time. Once that time is elapsed, you can remove the fabric and let it dry.
4. “Mild” detergents:
In Handwoven’s finishing instructions, it’s common to see “wash in mild detergent,” but what does that mean? Any of the three types of detergents listed above can count as mild detergents. Most mild dish soaps, including what’s often called “blue Dawn,” are actually detergents. Laundry detergents with minimal ingredients (no dyes or fragrances) or those marketed as being for delicate fabrics, baby clothing, or people with sensitive skin are also mild.
What About Soap?
What you don’t see listed above are any true soaps. Even though we often use the terms soap and detergent interchangeably in the United States, there is a difference between the two. Soap is simply some sort of oil or fat plus an alkali or base. To understand why this makes soap bad for textiles you’ve got to understand the basic chemistry. Most soaps are sodium stearate which is great at getting rid of dirt and oil. Unfortunately, sodium stearate can react with minerals found in water—especially hard water—to become calcium stearate or magnesium stearate. You might know this better as soap scum. While soap is great for cleaning many things—I’m a huge fan of castile and goat’s milk soap myself—it’s not great for textiles because it will leave that film on the fibers.
I won’t go into the complexities of the chemistry of a detergent here, but know that detergents contain ingredients to prevent this ionic exchange from happening. This is why most shampoos are actually detergents, as are “dish soaps.”
A Clean Finish
So there you have it! If you’ve ever looked at finishing instructions in an issue of Handwoven and wondered what on earth all those terms mean and how they differ from one another, now you know! And to learn more about the ins and outs and whats and whys of wet-finishing, make sure to check out Laura Fry’s course!
Happy Weaving (and Washing),
Featured Image: While soap can be beautiful and often smells wonderful, it’s not the best choice for wet-finishing handwovens. PHOTO BY VIKTOR FORGACS ON UNSPLASH