Acrylic paint, once dried, forms a plastic-like layer that adheres well to most surfaces, including fabric. However, if you want to make sure the acrylic paint doesn't wash off your shirt, you can follow these steps:
Preparation: Before painting on the shirt, wash and dry it to remove any sizing or residues that might interfere with the paint's adhesion.
Fabric Medium: Mix acrylic paint with a fabric medium specifically designed for acrylic paints. Fabric medium helps to make the paint more flexible and durable on fabric, preventing it from cracking or peeling. Follow the instructions on the fabric medium product for the correct mixing ratios.
Acrylic Paint Quality: Use high-quality acrylic paints. Cheaper, low-quality paints might not adhere as well to the fabric or might not last after washing.
Apply Thin Layers: Apply thin layers of paint instead of thick globs. Thin layers dry faster and adhere better to the fabric.
Heat Setting: After the paint has dried completely, heat-set it using an iron. Place a piece of cloth or parchment paper over the painted area and iron it on the appropriate setting for the fabric. This process helps to further bond the paint to the fabric.
Wait Before Washing: Give the paint enough time to cure and bond to the fabric before washing the shirt. Ideally, wait at least 24 to 48 hours before washing.
Hand Wash or Gentle Cycle: When washing the shirt, turn it inside out, use cold water, and choose a gentle cycle. Hand washing is even gentler on the fabric and helps prolong the life of the painted design.
Avoid Bleach and Harsh Detergents: Bleach and harsh detergents can deteriorate the paint, so it's best to avoid them when washing the shirt.
Keep in mind that even with these precautions, acrylic paint on fabric may eventually show signs of wear over time, especially if washed frequently. For best results, consider using a shirt that you don't mind dedicating solely to artistic purposes.