Dear Glass Detective,
I have been asked to take paint off of windows. The person said someone already tried and couldn’t do it. The paint has been on for years and the sun hits the windows hard. I know I will have to scrape, but is there a product that I can use and that will not hurt the glass at all?
Thank you for contacting the Glass Detective with your question regarding methods for removing paint from glass. This is a good, but not easily answered question. You see, a great deal depends on the type of paint that has been applied to the glass.
Some paints, such as water colors used for temporary window signage and holiday decorating, come off very easily with warm soapy water and a cleaning cloth. Other painted glass surfaces such as ceramic frit (baked onto a glass surface) are actually not removable. The paint/frit has become embedded (fused) onto the glass. As you have described your situation (you said the paint has been on the glass a long time, the sun hits it and that others have tried but failed to remove it), you may not be able to do much with it. There are also some paints used by glass artists which are not removable without scratching or damaging the glass. Latex paints are not too hard and some acrylic paints also can be removed with ease.
Also, depending on how old this paint actually is, be cautious of lead. If it is a residential window from a home built prior to 1978, there is a chance the paint contains lead which can be toxic. In this case certain guidelines set forth by the Environmental Protection Agency (EPA) must be followed. Read our blog to find out more on renovating homes where lead based paint could be present.
Typically, a razor blade held at a 45 degree angle to the glass surface used carefully (wear some gloves) will work well if a proper solvent or cleaner is also used. Do not go back and forth on the glass surface with the blade. Work in one direction and keep the blade clean. There are paint removing solvents that can be found online or in your local hardware store. Read the labels carefully. Most importantly, DO NOT use wire brushes, anything abrasive (sandpaper) or any chemicals or acids that could permanently stain or etch the glass surface. Experiment in a small area before attempting to do the whole piece and BE CAREFUL. Again … if you are going to use any type of solvent, read all labels and follow all directions. Use only clean, new razor blades.
The Glass Detective hopes this information is of some value to you. Good luck!