Dyeing polyester is possible at home and requires using the immersion process. It can take some time, patience and careful skills. The key is to make sure the water is as heated as it needs to be and that you are using the most sufficient products in order to dye the fabric. If you are a beginner with dyeing fabric, it is best to start with cotton first and then work your way up to polyester.
Make sure you have a well-ventilated area before you begin dyeing the polyester. Put on the latex or rubber gloves to protect your hands. Wash the polyester fabric in the 5 gallon pot on the stove. Once the water starts to warm up, add a small handful of soda ash and 3ml Synthrapol per pound of fabric. Let the fabric boil in this mixture for about 10 minutes in order to remove dirt and oils from the polyester.
Remove the polyester from the pot and set aside. Next, in a separate pot, boil 1 cup of water and then add the dye to the water. The amount of dye you add depends on the brand of dye and colour. For example, for light colours, dissolve 1.3 gm in the water; for dark shades, dissolve 8 to 15 gm. In another separate small pot, place 2 to 3 tbsp of the dye carrier in 1 cup of boiling water.
Set the 5 gallon steel pot back on the hob. For every 2.5 gallons of boiling water, add 2.5ml Synthrapol, 10 tsp white vinegar, the diluted dye carrier from the second pot in Step 2 and the dye. Add them in this order. Stir the water completely before adding each ingredient with the utensils.
Place the polyester into this large pot, and make sure it is brought to a boil while stirring. Simmer about 35 to 40 minutes (this all depends on what shade you want the polyester to be). Sift the utensil around in the pot, shifting the fabric so dye gets to all angles.
Bring a second pot of water to boil while your polyester fabric is simmering. It just needs to be large enough to hold enough water to cover the fabric. After the fabric is finished, immediately transfer the fabric to this second boiling pot of water. This is to help remove the chemical odours from the polyester.
Drain the 5 gallon pot with the dyed water carefully into a sink. Rinse out the pot, and refill it with water. Bring it to boil again and add 3ml Synthrapol. Transfer the polyester back to this pot and stir for about 10 minutes. Remove the fabric, and rinse in hot water in the sink.
Dry the polyester as usual, whether it is a line dry or in the machine dryer.
Never use an aluminium pot to dye fabrics in.