Soda Washing

Soda Washing[]

Soda washing is a technique where wick material is treated with sodium carbonate (also known as washing soda and soda ash) to improve its capacity and release characteristics. It is most often used with cotton twine but may apply to other materials as well. It does not seem to improve (or hurt) the performance of t-shirt yarn.

Handling! Washing soda is a very alkaline powder. Dishwashing gloves or rubber gloves should be used when handling it, and care should be taken not to inhale any powder.

Washing soda used to be a common laundry aid in the USA but has fallen into disuse. While it may be hard to find as a laundry aid, it can generally be found wherever pool supplies are found as it is a common ph-adjusting chemical used for swimming pools. Many hardware stores stock it (among pool chemicals).

if you have difficulty finding it, it is easy to make (as discussed below).

Twine new and used and whisperer — Soda washed twine compared to unprocessed twine

Using washing soda[]

Overview. The basic technique for soda washing is:

Skein your twine (or other cotton wick material). See below for more information about skeining.
Boil the material for an hour or more to completely shrink it.
Soak the material in a washing soda/water mixture for an hour or more. It can be left safely overnight but soaks much longer than an hour do not seem to increase the effectiveness.
Unless you are dying the material (with fiber-reactive dye), you need to thoroughly remove the soda wash from the wick. Squeeze out the soda-wash. Soak the material in fresh water for a few minutes. Thoroughly rinse the wick. Repeat.

Brian Lawrence who discovered this technique adds the washing soda directly to the water that the wick was boiled in once it cools to about 150F or so. Others remove the twine from the water in which it was boiled, squeeze it to remove excess water and then perform the washing soda soak in room temperature or hot water.

The soak should be about 1 cup washing soda per 1 gallon of water which is 1 tablespoon washing soda per 1 cup water or 15 ml washing soda per 250 ml water. You can use higher concentrations, too, but it is not clear that there is any benefit. Edward has used up to 2 tbsp. washing soda per 1 cup water.

WARNING! Washing soda is very caustic. Use gloves when handling it and when you might come into contact with the soak water. Do not breathe in the washing soda powder. A dust mask is recommended.

Preparation - Skeining the Material[]

20130209 3957 twine prepped for boiling — Twine skeined and ready for boiling and soda-washing

In order to keep the material from becoming tangled during boiling and soda-washing, you need to make a loose coil and to secure it so that it does not uncoil. In the picture, the coil has been secured with zip ties, but you can use twist ties or pieces of string.

Sources[]

You can make it yourself (see below), and it can be found inexpensively at places that sell swimming pool supplies and fabric dyeing supplies. It is generally much less expensive to purchase it from a pool supply place (many hardware stores carry it) than it is to make it. When sold with pool supplies, read the ingredients labels. You want a product that is 100% sodium carbonate (or soda ash or washing soda).

It is sometimes available in supermarkets with laundry detergent; although, it is less widely available than in former times.

How to Make Washing Soda[]

To make washing soda, pour baking soda onto a cooking sheet or other shallow pan and cook for at least 1 hour at 200F or higher. Using a higher temperature speeds the process. Reports on the internet indicate that many people use temperatures of 300F to 400F.

Brian Lawrence uses 200F for at least one hour. Edward Spiegel has reported using 400F for an hour. It is important to make sure that you cook the baking soda until the transformation to washing soda is complete. The heat drives off moisture from the baking soda and cleaves the molecule.

When the conversion is done, the appearance will have changed noticeably as seen in the picture on the right (click to enlarge).In the photo, the baking soda is on the left, the washing soda is on the right. Baking soda is fluffy with a tendency to clump. The washing soda is more like fine sand or dust, with a grainy texture.

Handle the powder with gloves and be careful not to breathe in the powder.