Q. My favorite medium is acrylic paint, and I have some Plexiglas panels that Id like to try to paint on with them. Do you have any suggestions on how I should go about this?
Lionel H. Abshire
Baton Rouge, LA
A. In general, its best not to paint on nonporous materials, such as Plexiglas. However, theres a long tradition of painting on such supports as polished stone, glass, metal and, more recently, plastics. While there are some examples of well-preserved paintings on all these surfaces, the most common problem with this practice is the paint flaking off. Paint needs tooth, or something to grab on to, to make a strong bond with a surface. Ideally, paint is applied to a surface that can absorb it to some degree, which is one reason why canvas, paper, wood and gesso are such standard materials. When a surface is impermeable, like Plexiglas is, the paint has nothing to sink into.
Paints can have some natural adhesive properties, though, and the resins in acrylic paints specifically have been used to create adhesives. One way to increase the chances of getting your acrylics to stick to Plexiglas is sanding the smooth surface to give it some tooth. In the example at right, this procedure gave the paint a stronger hold, even when scratched vigorously with a fingernail. But the downside of sanding the Plexiglas, in addition to the labor it involves, is that if you value this support for its smooth surface or its transparency, both of these features will be lost. The point of sanding, after all, is to eliminate the smoothness by scratching the surface, which then clouds its appearance by scattering light. If you paint very thinly, youll surely see the texture of the sanding marks through your paint layer, and if youre interested in reverse glass painting (viewing the painting from behind) youll almost certainly alter the effect.
If its carefully handled and properly framed and stored, however, your acrylic painting on smooth Plexiglas stands a chance for durability. To this end, be sure to keep other objects from touching the paint surface. Proper framing will protect the support from repeated bending, which puts the paint layer at risk for shearing off, and a rigid frame or additional support becomes even more important with a very large sheet of Plexiglas, where the tendency to bow is higher. Framing a painting also lends it a sense of importance that deters curious onlookers from touching the art and conducting their own fingernail tests.
Finally, remember that the use of innovative or nontraditional materials may have unintended consequences, and theres no guarantee of how the painting will fare in the long term. In your case, Plexiglas simply hasnt been around long enough to know that. But while the risks of using nonporous supports are clear, so too is the beauty of those pieces painted on them that so far have survived intact.
A signature member of the National Watercolor Society, Watercolor West and the Rocky Mountain National Watermedia Society, Catherine Anderson lives in Glen Ellen, California. Visit her Web site at www.catherineanderson.net.