1
Cover your work surface with plastic or paper to preserve the surface. Use plastic gloves to protect the tumbler from oils on your hands or wash your hands to remove any oils.
2
Wash the tumbler both inside and out with a soap detergent used for grease removal. Clean the tumbler with rubbing alcohol to remove any remaining oil on the tumbler and dry completely.
3
Spray the tumbler with a plastic primer to help the acrylic paint adhere to the plastic. Allow the spray to dry for a few minutes and wipe off any excess.
4
Sketch a design on the tumbler with a fine point permanent marker. Use a marker close to the color of the tumbler to avoid lines showing when the painting is complete.
5
Paint the sketch with acrylic paints, starting with color you want to feature. Use a dry, clean, synthetic acrylic brush for each new color. Brush the paint on smoothly and evenly for a consistent finish. If applying paint on top of another color, allow the original color to dry completely to avoid smudging. Clean the paint brushes immediately with soap and water to avoid paint clumping on the brushes.
6
Add detail to the sketch, using permanent markers. Allow the painting to dry completely.
7
Spray a clear coat sealer on the tumbler and let it dry. Repeat this process two more times, allowing the sealer to dry between applications