Soda Ash & Urea

SODA ASH:
If you pre-soak your tee shirts in soda ash, it helps to retain the dye.

Prepare your soda ash mixture in a tub or sink. For every gallon (3.79 l) of water, mix in 1 cup (236.5 ml) of soda ash, also known as sodium carbonate.

UREA:

Wear your dust mask & gloves! Measure urea and warm water into a container, an old pitcher works well. Use the chart below for amounts. Paste up your dye with the urea water (see below), then add rest of water and stir ‘till thoroughly dissolved. Pour into squeeze bottles with afunnel. An already wet, tied up adult tee will absorb about 4 oz of liquid dye, depending on how much you apply. Use this as a guide to help you decide how much to mix up. Check the name of each color on the label of the jar, some colors need more dye, they are marked with an * or ** by the name.

• Dharma Trading Company Soda Ash & other chemicals
• Tulip One Step Fashion Dye Soda Ash
• Soda Ash Dye Fixer
• Urea 

BAKING SODA ALTERNATIVE:
If you don't have any soda ash, you can convert baking soda by baking it:

If you cannot buy sodium carbonate anywhere (an unlikely problem in most countries), you can make your own sodium carbonate by heating sodium bicarbonate. Baking soda can be converted to soda ash by temperatures above 50°C (122°F), whether by steaming, boiling, or baking. To convert a quantity of baking soda to soda ash in your oven, place it in a glass baking dish and heat it, uncovered, for an hour at 400°F (200°C).

or use the microwave:
heat a small amout in the microwave for about 10 seconds for the same effect.

or follow these instructions http://www.ehow.com/how_8128014_use-soda-ash-fixer-solution.html

• Pour one gallon of warm water into a large microwave-safe container. 
•  2 Add 3 cups of baking soda per gallon of warm water to the container. Stir the mixture well with a wooden spoon to mix in the solution; it may not dissolve, as the water temperature has to be very hot to dissolve baking soda. 
•  3 Add the garments you wish to dye. Microwave the solution and garments for 10 minutes to increase the temperature and dissolve the baking soda into the garments, creating the same effect that the soda ash would have at room temperature.