Soda Ash, also known as sodium carbonate, is a workhorse in the dye studio. It may be used in small amounts to alter the ph of a madder dye bath which causes it to redden, or used for scouring cellulose fibers. It is also an easy way to raise the pH of an indigo vat. In addition, it is a mild base that increases the pH of an indigo vat or adds alkalinity to a dyebath to modify its shade.
- When balancing an indigo vat, plan on using between 250-500 grams (8-16 ounces) of Soda Ash.
SCOURING SILK FIBERS
Silk yarn and yardage is generally sold already well scoured; if it is very soft and white, then the sticky protein called sericin has already been removed. However, if you are working with silk noil, raw tussah yardage or silk yarns that feel stiff, then scouring them will help improve color yield and quality in the dyed goods.
CALCULATING THE AMOUNTS
Soda Ash: Use 2% or 1/2 teaspoon of soda ash per 100 grams of fiber.
Vinegar: Use 5% or 1 teaspoon of white vinegar to neutralize the fibers after scouring.
WHAT YOU WILL NEED
- 100 grams of silk fiber
- 1/2 teaspoon of soda ash
- A container to dissolve the soda ash
- A large stainless steel dye pot, large enough to hold your fibers with plenty of room to move around
- A large stainless spoon or tongs
- Heat source
Wet out the soda ash first with a little cold water, and then gradually add boiling water to dissolve.
Fill a dye pot with enough room temperature water so the fibers move easily and place on a heating source. Add the wet fiber to the dye pot and slowly bring the temperature to 160°F, rotating the fibers gently.
Hold at 160°F for 30 minutes.
Remove fibers from the dye pot (be careful as it is very hot), rinse in cool water, extract excess water and proceed to mordanting. If the scour water is very dark colored, you may need to scour a second time to remove all of the impurities from the fibers. Repeat the steps, above.
At the final rinse, add 1 teaspoon of white (distilled) vinegar to the rinse water and let the fiber soak in the vinegar water for 20 minutes. Remove, rinse in cool water, and proceed to mordanting.