Glass is a satisfying medium for your paint projects. Hand-painted wine or margarita glasses make a great housewarming gift. But you don't want to give your new neighbour a glass that can't be run through the dishwasher. When painting on glass you want to make sure that you have performed all of the necessary steps to make sure that the paint is both heat- and water-resistant. Properly preparing the surface will make your paint job look better and last longer.
Thoroughly clean the glass using an ammonia-based cleaner. A perfectly clean surface will help the paint adhere through abuse from high temperatures.
Dampen a piece of fine-grit sandpaper. Dip the glass in water. Gently rub the glass with the wet sandpaper. Wet sanding will reduce the amount of dust and will also keep the glass from being visibly scratched. Rinse the glasses with clean water. Allow the glass to dry.
Apply glass conditioner to the glass. Glass conditioner is used on boat and car windows as well as your glass cooktop to strengthen the glass and fill in minor imperfections. In this application, the conditioner works like a primer coat, sinking into the grooves in the glass and bonding with the paint to make it more durable. Use a clean rag to rub a thin layer of conditioner onto the glass surface. Allow the conditioner to dry.
Use a sponge or brush to apply enamel paint to the glass in your choice of designs. You can paint freehand or use a stencil, depending on your level of artistic talent. Multiple thin coats of paint will withstand heat better than one thick coat. Plan to apply up to six thin coats of paint for best results. Choose an enamel paint formulated for glass that is food-, microwave- and dishwasher-safe. Delta Creative Perm Enamel is a good choice for painting glass. Allow the paint to dry completely.
Apply a layer of glaze over the paint to further protect the paint from heat. Use a clean paintbrush to apply the glaze. Apply one thin coat of glaze. Allow the glaze to dry.
Set the glasses aside in a safe place and let them cure for 10 days. After 10 days the glasses will be dishwasher- and microwave-safe.