For a personalized bathing suit, dyeing is an enjoyable and attractive option. A swimsuit can be dyed one solid color or tie-dyed in a variety of bright or pastel colors. It's important to use color-fast dye and color-fast fabrics to avoid running colors. Choose the right fabric for a swimsuit that can be dyed. For the easiest dyeing, choose a swimsuit that is mostly cotton. Dye outdoors or cover floors and counters with plastic before dyeing to avoid unwanted stains.
Wet the swimsuit. Soak it with warm water so that it is completely wet.
Mix the dye in a plastic or stainless steel container. Using a porcelain sink will dye the sink, and the stains do not come out. For fabric-reactive dyes in powder form, use 3 gallons of warm water, 1 to 4 tsp. of dye and 2 cups of salt. Stir until salt and dye dissolve.
Place the swimsuit in the dye bath. Submerge the suit completely and stir periodically. It should be in the bath for 20 minutes.
Dissolve soda ash. In a separate metal container, dissolve 1/4 cup soda ash in 1 cup of water. After the swimsuit has been in the dye for 20 minutes, add the soda ash mixture.
Soak the bathing suit for 50 minutes. Again, stir the mixture periodically to get even color throughout the swimsuit.
Remove the swimsuit and rinse. After the water runs clear, wash, rinse and dry the swimsuit according to the fabric care instructions.