Polymer clay contains no natural clay minerals. It is made from a PVC base with liquid plasticisers, which makes it possible to mould and sculpt it just like a natural clay. Polymer clay is extremely strong when baked, with most items being able to withstand being dropped. Although polymer clay is available in a wide range of colours, some projects may benefit from additional finishes in the form of painted features that are added by hand. Other finishes, such as antiquing or adding metallic effects are possible with other painting techniques and materials.
Acrylic paints are available in art or craft stores. Acrylic paint for craft use is less expensive than artist-quality acrylic paint, but both are suitable for use with polymer clay. Use acrylic paint after baking the clay as the water content in the paint can bubble in the oven. Crackle effects, however, are created by painting raw clay with acrylic paint and then stretching it through a pasta machine before baking. Create an antique effect with acrylic paint by applying the paint and then wiping it off with a paper towel while it's still wet. Some of the paint will cling in the crevices and any cracks in the clay, giving the item an old and worn look.
Oil paints can take a long time to dry completely, sometimes up to 6 months, so are not suitable for crackling techniques on polymer clay. Use linseed-based oil paints to tint liquid clay or create marbling effects by mixing oil paint into raw polymer clay. Experiment to see how long your oils take to dry before you commit to using oils on a finished clay project.
Use metallic powders to give Polymer clay a gold, silver or bronzed appearance. Paint metallic powder onto areas of clay, with a fingertip or a cotton swab, either before or after firing. Knead it into clay to give a shimmery effect or used it as a mould release. The clay needs to be glazed or varnished after firing to prevent the powder from rubbing off.
Inks, Dyes and Dimensional Paints
Many of the inks and dyes used in rubber-stamping crafts are suitable for use with polymer clay. If using alcohol-based inks to colour uncured clay, allow the alcohol to evaporate before baking it. The pigment inks used in rubber stamp ink pads can be used on polymer clay before baking. Dab it on directly from the stamp pad, or use a brush or small pad to transfer the colour to the clay. Accentuate textured clay projects with dimensional craft paints by sponging the paint onto the surface of the clay then wiping off the excess before baking it as normal.