Doing decoupage on glass can be trickier than on other mediums because of its smooth surface, and since it is often clear and exposes mistakes. To keep decoupaged glass as perfect as possible, clean the glass thoroughly before beginning the project, use laser copies of the paper to be decoupaged to prevent color bleeding, use watered down glue, and be sure to remove any air bubbles before letting the piece to dry. Following these tips can help result in the most professional look.
It is usually easier to get the paper or other artwork to stick to the glass if the surface is clean first. For best results, clean with soap and water and then go over the piece with rubbing alcohol. Finally, dry the glass before beginning any decoupage work.
Although an original copy of the artwork can be used, it is safer to make a copy in case the image gets ruined. Using a copy from a laser printer instead of an ink-jet printer is ideal because laser printer ink does not run or smudge when wet, as ink-jet ink will.
To decoupage on glass, first arrange the images as you want them to look on your final product. If the piece is a serving dish, for instance, it is a good idea to place the images on the underside. That way, chemicals are only used on the side of the dish that food will not touch. Once the images are arranged, dip a foam brush into water, then into a mixture that is three-parts glue and one-part water. A specialty decoupage product will also work. Coat the glass with glue first, then apply the image. Do not be afraid to use too much glue, since too little will result in streaks, and any excess can be wiped away or squeezed off.
Next, adhere the image to the glass based on the original arrangement. To eliminate any air bubbles in the artwork when you decoupage on glass, simply rub the image smooth with a finger. A special implement called a rubber brayer, made to smooth bubbles, can also be purchased for this job. It resembles a small rolling pin, but is made of rubber instead of wood.
If using multiple coats of glue, each coat should be allowed to dry thoroughly before adding another layer. Once all of the layers are completely dry, a sealant or clear coat should be applied to protect the decoupage on glass. Also, when finished, the item should be washed carefully so the work is not damaged.