We get mordant questions all the time at Botanical Colors so why not create Mordant Monday??? Got mordanting questions? Email [email protected]
YOU ASKED: I’m confused about the different types of aluminum mordants. I want to do some dyeing of fabric (silk, cotton) and also some wool. Do I need to use different aluminum mordants for these different fibers? I was told that I needed aluminum acetate for plant fibers and aluminum sulfate for protein fibers. Is that true? I have alum sulfate and would love to use it for both if that is workable.
KATHY ANSWERED: Mordanting provides lots of options using mineral mordants (alum-based and iron-based), tannins, and also plants that accumulate aluminum in their roots or leaves, so it can get complicated quickly. Some mordants work well with one type of fiber, but most mordants will work with all fiber types with some minor modifications. On top of that, there are some dyes that don’t require a mordant adding to the complexity of remembering and sorting things out.
You can use aluminum sulfate for both types of fibers. Follow the protein mordant instructions for aluminum sulfate and the tannin-alum instructions for cellulose fibers. Both methods use alum sulfate, or, if you have it, aluminum potassium sulfate. Both of these preparations are commonly called “alum.” I’ve linked both sets of instructions.
My advice is to find the mordants and processes that work for you and your artwork and then get good with those. If you decide to stick with aluminum sulfate, you will get excellent results on both animal (protein) fibers and plant (cellulose fibers) if you use their respective mordant processes.
YOU ASKED: I have a 60% hemp and 40% silk fabric, what would be the best way to mordant this fabric for natural dyeing?
KATHY ANSWERED: I tend to mordant for cellulose fibers when I have a cellulose and protein blend. Check your fabric to see if it requires scouring. Often blends do not need a scour as they are already thoroughly processed to create the blend and a light wash should be sufficient. Your mordant choices are tannin-alum, aluminum acetate and aluminum triformate.
YOU ASKED: I know that aluminum triformate can be made and used over time. However, what would happen if I put some silk scarves and bamboo socks in and forgot about it? Like for a week? Is all okay or do I need to scour and start over.
KATHY ANSWERED: This is exactly how I use aluminum triformate. I throw things in there and use them over the course of a few weeks and get really good results. As long as the fibers aren’t getting moldy, you should be fine and make sure the fabric is completely covered by the mordant and you don’t get bubbles in the fabric. You don’t need to re-mordant, just remember to rinse the fibers before proceeding to the dye pot.
YOU ASKED: I’ve mordanted both silk and cotton fabric for use later. Should I wet the fabric with water or mordant before eco dyeing with flowers and leaves? And can I use the spent mordant water as my steaming water?
KATHY ANSWERED: We recommend that you dampen the fabric prior to moving to the dye process, so yes, you should dampen and squeeze out the excess water. Regarding the mordant water: I believe that you can but mordant baths may be reused several times so you may want to save the mordant bath for future mordanting. It’s my understanding that steam baths use a very small amount of water if you are able to use another water source. Rain water?
YOU ASKED: I’m so thrilled to use aluminum triformate for mordanting my yarn! It stays softer and less felted. And I love not dealing with hot pots… any chance you have some more cold water magic for scouring?
KATHY ANSWERED: If you are doing a simple wash of already scoured wool, a lukewarm soak and rinse might do the trick. However, if you are trying to clean raw wool, I’ve always used a hot water scour. I have heard that some cultures will use Fuller’s Earth or other absorbent clay and sprinkle it over the wool and leave in the sun so the lanolin is absorbed, but I have never tried it. I also just heard about a traditional technique where greasy raw wool fleece is left to ferment and the combination of lanolin, sheepy stuff, and water creates a “soap” suint that consumes the dirt and lanolin. This is not the kind of soap you would use as a body wash, BTW. The combination takes time and is very “aromatic” but saves on water and resources if you live in a sunny location. The water can be reused to clean more greasy wool, saving water and energy.
Using plain water, sun’s heat, time, and a tub with a lid does work on submerged dirty raw wool fleece over a couple of weeks. Suint (largely sheep’s perspiration and dirt) is water soluble, comes with the fleece, and is the key to forming the “soap” in the covered tub. Dissolved suint remains in the water and makes the solution more effective each time another dirty raw wool fleece is submerged in it. The smell of the fleece goes away after a thorough rinse with water followed by drying. After that, the smell doesn’t return when the wool fleece is rewetted as for dyeing or washing with detergent to remove lanolin (also known as wool grease or wool fat). Incidentally, because the “soap” solution in the tub never attains the 110°F (44°C) melting point of lanolin, it remains in the fleece unless deliberately removed by scouring and heat. It is the lanolin remaining in the fleece that provides the grease that spinning in the grease is based on. Once you have spun this kind of greasy wool, you’ll never go back to spinning wool fleece that is dirty and smelly from suint. See Spin-Off Magazine, https://spinoffmagazine.com/wool-basics-what-is-grease/
Thank you, Glenna! This is so interesting because we ended up doing something like this out of desperation when working with a wool cooperative that didn’t have access to a lot of fuel for boiling pots of water and hot water scouring. We ended up soaking the fibers for a couple of days so we didn’t use their precious energy resources and the wool came out much cleaner. It wasn’t the full suint process but it definitely helped. Although I’ve avoided raw fleeces in the past, now I’m fascinated with this idea. Thank you for sharing the the reference and the thoughtful comment! Kathy