Unlike animal and plant fibers such as wool or cotton, acrylic yarn is synthetic and does not absorb dye easily. One way to successfully change the color of acrylic yarn is to use light-colored yarn and a special dye called disperse dye. While disperse dye will change the color of light acrylic yarn, the result is always a pale to medium tint.
Disperse dye can be purchased online; note that it is not the same as the universal dyes you typically find in the craft store.
Spread newspapers or a plastic covering on the work surface to protect it from staining. Put on rubber gloves to protect your hands from the dye.
Disperse dye can stain countertops, so be sure to cover the entire surface and have paper towels nearby for spills.
Remove any dirt, oil or other residue from the yarn by soaking it in hot water along with 1/2 teaspoon of soda ash and 1/2 teaspoon of liquid detergent.
Dissolve the disperse dye in 1 cup of water, adding 1/4 teaspoon of dye for a pale color and 3/4 teaspoon of dye for a medium color. Allow the mixture to cool to room temperature; then stir to further dissolve the dye.
Kitchen utensils used for dyeing should never be used for food preparation.
To remove any remaining powder from the dye, strain the dye mixture through an old pair of nylon stockings by stretching the stockings over a bowl and pouring the dye into the bowl. Repeat one time. Discard the stockings.
Fill a large pot with 2 1/2 gallons of water and use the meat thermometer to heat the water to 100 to 105 degrees Fahrenheit.
Once the water is at the correct temperature, add the strained dye, 1 teaspoon of detergent and 1 1/4 teaspoon of vinegar to the dye bath. Stir.
Add the yarn to the dye bath, ensuring all the fibers are submerged in the water.
Stir the dye bath constantly. At the same time and over the next half-hour, slowly increase the temperature to a boil.
Leave the yarn in the boiling dye bath for approximately 40 to 60 minutes, stirring and checking every few minutes to ensure that the entire skein of yarn is submerged.
Remove the dye bath from the heat and allow it to cool to below 150 degrees Fahrenheit.
Run cool water into the dye bath to complete the cooling process. Remove the yarn from the bath and rinse it under cool water until the water runs clear.
Allow the yarn to dry completely overnight.
If dyeing the acrylic yarn does not produce the color you desire, you can also try painting your acrylic yarn with acrylic paint.
Immediately wipe the stovetop clean using paper towels to avoid staining.