Polyester can be tie-dyed, but it's not the easiest process in the world. Natural materials like cotton and rayon absorb fabric dye better, and when used on polyester, the dye creates a subdued color if any -- not exactly the effect you want in a tie-dyed piece of clothing. Luckily there are specific dyes created for polyester that can be used to get the look you want, but it's not recommended for novices.
Choose Your Dye
To effectively dye man-made fabrics like polyester, nylon and acetate, you need disperse dyes, which have limited solubility in room-temperature water. These dyes are also nonionic, meaning their atoms are held together through chemical bonding. Such dyes include iDye Poly, ProSperse and KraftKolour, among others.
Turn Up the Heat
Immersion-dyeing polyester requires a much higher temperature than other fabrics -- you're going to need to boil your water on the stove before expecting any color absorption. You also usually need to add a dye carrier or color intensifier to help the color soak into the polyester, and this can release a noxious odor. The material needs to stay in the boiling dye for 1/2 to 1 hour with constant stirring for even coverage.
Brush It On
An alternative to immersion dyeing for polyester fabrics is to manually apply the color with a paint brush, sponge brush, syringe or squeeze bottle.
Wash and Tie
Once you have your disperse dye and carrier, and you're prepared to tackle the boiling and dyeing process -- or the brush or squeeze bottle application -- wash your polyester material in hot water to remove dirt, oil and sizing. Then gather random bunches in your material to get it ready for tie-dyeing, and secure each scrunched area by tying it with string or a rubber band.
If you don't need a 100 percent polyester material, you can use a poly-cotton blend. You can also use regular fabric dye with these fabric blends, but it won't produce the same vibrancy that it would if you were to use a 100 percent cotton material
Wrap the Fabric
After you've tie dyed the material, wrap it in plastic and let it sit for at least a four hours to cure -- and up to 24 hours for darker colors. The room temperature needs to be over 70 degrees for proper color fixing.
Rinse and Wash
Once the color is cured, untie the material and rinse it repeatedly in warm water. Then wash it in hot water and synthrapol, a pH-neutral industrial strength detergent used to remove any excess dye from the fabric.