When it comes to decorating surfaces like glass and porcelain, acrylic paint is an excellent choice. Flexible and waterproof, this polymer-based paint is easy and safe to work with and will provide vivid color to your projects. In order to get the most out of painting glass with acrylic paint, it's important to follow a few basic rules and guidelines in selection of paint, preparation, and application of color to glass surfaces.
Glass-Specific Paints
Though you will likely have good luck painting on glass with any kind of good-quality acrylic paint, for certain projects you may want to consider acrylic paint designed for use on glass. For example, if you plan to paint dishes or other items that will experience regular use and washing (including dishwasher cleaning), these paints are designed to be extra durable. Glass paints are also the best option if you want a transparent, stained-glass look, as standard acrylic paint will be opaque. Glass paints and painting kits are commonly available in craft stores.
Preparing Glass
Before you paint on any glass surface, you must properly prepare the glass. This means making sure that the glass is fully clean and dry. Work in the most dust-free environment you can find. Both dust and water will interfere with the adhesion of the paint. For the same reason, be sure to dry your glass surface with an absorbent but lint-free towel, such as a dish towel.
Paint Thickness
When working with a non-porous surface such as glass, it's important to keep your paint from becoming too thick. Though acrylic paint is highly adhesive, mixing it with too much water can be problematic since it will not be absorbed by glass as it would be by paper or fabric. For this reason, start with paint at its thickest, just as it comes from the tube. Don't dilute your paint until you're certain you need to, and add the smallest amounts of water at a time to make sure you don't go overboard. Keep excess water out of your paint-brush tips as you work by blotting them against a paper towel or rag after washing them between color applications.
Also, if using an opaque acrylic on clear glass, pay attention to how thickly you apply the paint; applying it in very thin coats will cause the paint to appear somewhat translucent once it has dried. This is easily fixed by applying a second coat of paint, but it's easier if you avoid the problem on the first try.
Gravity
When painting any glass that's intended to be hung up, such as a mirror or window, it is best to lay the glass flat while painting. This will ensure that the paint stays where you put it rather than dripping down the glass. If the surface you're painting cannot be moved and must be painted while hanging up, it is even more important to work with thick paint that won't run. If the paint you are working with for such a project is too thin, you can counteract this somewhat by painting with a sponge or cloth-tipped brush that will absorb moisture. You can also keep a rag on hand; watch for paint drips and wipe them off as they occur.
