Enamel paint is a high-gloss oil-based paint that is typically used on hard, non-porous surfaces such as metal, whereas acrylic paint is a chemical-based paint that is best used on porous and outdoor surfaces due to its ability to expand and contract with rising and falling temperatures. Emulsified polymers give acrylic paint its flexibility. These flexible bonds make acrylic paint ideal for painting on non-porous surfaces as well as porous, because air is what allows the polymers in the paint to maintain their bonds.
Acrylic paint also wears much faster than enamel paint. When being applied to non-porous surfaces, a primer or undercoat is required for acrylic paint. If acrylic paint is not allowed to properly breathe, it may split or crack.
Enamel's slower drying process is the direct result of its oil base. Although enamel paints are slower to dry than acrylic paint, they stand up to handling and high traffic very well and are easy to clean. The stability of enamel makes it a favorite of model builders. Although enamel is not traditionally considered an artist's paint, several famous artists have successfully incorporated enamel into their works. Pablo Picasso, for example, created works of art using a commercial-grade enamel paint.