Scouring your Fabric (Soaking Method)

Welcome back to season two of Plants to Dye For! Last year we learned about the history of dyeing with plants, how to prepare plant-based fabric, and how to dye it (see Plants to Dye For: Wrap Up). It was satisfying to see the white dish towels dyed to beautiful shades of brown and yellow using weld extract, walnut hulls and onion skins (and frustrating when the towels that were dyed with red cabbage faded from beautiful blue to dingy white). This year we'll try a few more projects.

Today I'm trying out another scouring technique, which is to soak the fabric over night in boiling water and scouring agents. I'm also trying out the idea of pre-scouring a larger quantity of dish towels. Fabric preparation is so important, but takes time. My plan is to separate the practical process from the creative process, by preparing a stockpile of scoured fabric for when the creative mood strikes! In this project I scoured 14 dish towels, most of which were used in the red cabbage project last year (see Dye Project: Red Cabbage). I also threw in an old cotton T-shirt just for fun.



I processed two batches of fabric, each weighing a little over a pound. The weights and measurements are not exact for the scouring process, but are provided as a guideline. I used Synthrapol and soda ash for the scouring agents. Synthrapol is comprised of water, isopropanol alcohol, and detergent. The detergent molecules surround impurities on the fiber, and water rinses them away. Soda ash (sodium carbonate) neutralizes the pH making it easier for dye to bond to fibers.

Scouring agents - Synthrapol and soda ash

The basic process for this technique:

1. Prewash the fabric. 
2. Soak the fabric overnight in boiling water and scouring agents. 
3. Rinse the fabric in cold water, then wash in the washing machine.

For equipment I used a large plastic bucket from the hardware store, and boiled about three gallons of water in the microwave using a one quart Pyrex measuring cup, and on the stove top using the tea kettle. I worked in the kitchen, since no fumes are generated, but used rubber gloves when handling the fabric, since soda ash is caustic. I also used a wooden paint stick from the hardware store for incorporating the scouring agents, and rotating the fabric periodically while soaking.

Large plastic bucket for soaking fabric

First, prewash the fabric in the washing machine with one teaspoon Synthrapol. Since I'm reusing the dish towels that I dyed with cabbage last year, I'm using Synthrapol to remove all traces of dye and impurities from that project. If you are processing new fabric, you could use detergent.

Then add the three gallons of boiling water to a bucket, and stir in:

• 1 tsp Synthrapol 
• 4 tsp soda ash

Add the dish towels (and T-shirt) and soak overnight. Stir periodically to rotate the fabric. After about half an hour, the water starts turning brown with impurities.

The satisfying brown indicates impurities are being removed from the fiber

 The next day, rinse the fabric in cold water, and squeeze out excess water. Wash the towels in the washing machine (no detergent). Optionally add an extra rinse cycle.

Air-dry the scoured fabric, then store for future use

At this point you can immerse the wet fabric into your mordant, brightener, or dye bath, or you can air-dry the fabric, and store it until needed. Label it so you know how it was scoured. Since I'm experimenting with doing these processes in batches, I air-dried the fabric, labeled it, and put it away until I'm ready for the next process. We'll delve into these processes in later posts.