Thursday, November 3, 2016

5% Dye Concentrates


Most of the time when I dye a lot of fabric, I work with 5% dye concentrates rather than with dye powers. To make 5% dye concentrates (or dye stocks), you mix 5 grams of dye powder with 100 milliliters of water. If you want more dye stock than 100 ml., you would increase both the dye powder and the water, but keep the proportions the same. For example, if you want 250 ml. of dye stock (roughly one American cup), you would mix 12.5 grams of dye powder with 250 ml. of water.

There are a couple of methods for making dye concentrates. The first involves using urea water to dissolve the dye powder, and the second involves using urea granules along with the dye power. Urea is a chemical that helps the dye powder dissolve more easily.

Be sure to wear a mask and gloves when working with dye powder and other chemicals. Either work in a dye mixing box or in a sink, lined with damp paper towels, below the level of your face. (For more information on this method of working in a sink, see my earlier blog post in which I describe this method of measuring dye powder.)

A well-used cardboard mixing box







Dye being weighed in a sink, below face level. Here the dye is measured into a cup, not a bottle
Method 1
Put your dye mixing container (usually a wide-mouthed bottle with a tight fitting lid) directly on the scale, and tare the scale to zero. Use a spoon to take the dye powder out the dye container, and tap the spoon containing the dye powder directly into the dye mixing container until you reach the required weight. Warm the urea water in a microwave to about 95-105 degrees F (35-40C). Pour the correct amount of urea water into the bottle, and shake well. Make sure the bottle has a tight fitting lid. As you pour the urea water into the bottle, pour some of it over the spoon to get off the last bits of dye powder. Shake the bottle well until the dye is fully dissolved.

This method assumes that you have urea water on hand. Urea water is made by dissolving urea granules in water in a 10% ratio. That means that you use 10 grams of urea for each 100 milliliters of water. If you want to make one gallon of urea water, dissolve 400 grams of urea in 4 liters (roughly one gallon) of hot water (120 degree F or 49 degrees C). Shake until well dissolved. You can keep urea water for many months. If it begins to smell like ammonia, discard it.

Method 2
This is the easier method for mixing dye concentrate. Put your dye mixing container (usually a wide-mouthed bottle with a tight fitting lid) directly on the scale, and tare the scale to zero. Use a spoon to take the dye powder out of the dye container, and tap the spoon containing the dye powder directly into the dye mixing container until you reach the required weight. After measuring the correct amount of dye, add a small amount of urea granules to the dye powder. I usually use half a tablespoon of urea granules if I am making 1 cup (250 ml) of dye stock. The exact amount doesn’t matter, though err on the light side since you can always add more urea. Add the correct amount of warm water (95 to 105 degrees F or 35-40 degrees C) and shake the bottle well until the dye powder is fully dissolved.

When the dye powder is dissolved, the dye concentrate will be translucent, and you will not see any undissolved dye particles in it.

Partially mixed dye 



 
Fully mixed dye which is now translucent








2 comments:

  1. Do you use salt in your dyeing? Benn and Morgan mix up a paste with dye powder and water and then add strong salt solution. So I keep 2 soda ash buckets, one with salt and one without, depending on whether I am going for tray dyeing or low water immersion dyeing.

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  2. Yes, I do use salt. I keep 10% salt stock in my studio and I add it to my dye bucket in the correct amount as I prepare the dye bath. The workbook part of my book, Dyeing Alchemy, does all the calculations I need for the water, salt stock, dye concentrate, and soda ash stock, depending on the initial weight of fabric and my desired depth of shade. Most of the time, I add the soda ash stock to the dye bath after about 15 minutes of dyeing the fabric with dye, water and salt stock. I then leave the fabric in the dye bucket for at least another hour.

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