You have a decal you want to remove from your car windshield. What you should do depends on the temperature, the sticker adhesive, and the decal’s materials. Learning a little bit about the materials can help you decide what to do, when you want to .
Stickers use a glue called a pressure sensitive adhesives (PSAs) to adhere it to the window. It’s called “pressure sensitive” because the bond is made by pressing the sticker onto the glass.
PSAs are generally made from rubber or silicone, and made sticky by adding a tackifier. The tackifier is usually a resin, solvent, or a special silicone solvent. These has these characteristics:
- Soften with heat. Gets brittle with cold.
- The glue softens when more tackifier is added, or something mixes with tackifier and softens it.
- The bonds hold harder if you pull it quickly.
If the Day is Cool, Scrape it Off
If it’s a cool day, the adhesive might be more brittle. You can try to scrape it off with a razor blade. Use the single bladed kind, in a holder.
If the Day is Warm, try to Peel it Off
Pick at one corner of the sticker, until you lift a piece big enough to pull on. Pull it slowly, because the adhesive may grip harder if you pull faster.
You can soften the adhesive more by using a hair dryer to heat up the area. Some adhesives, particularly the silicone ones, are designed to release when it’s heated.
Windows stickers are typically made of plastic or vinyl. Typically, the adhesive is silicone-based. These may respond to vinegar.
Some silicone glues are made sticky with acetic acid, aka vinegar. Try using a little vinegar on a cotton ball to loosen the adhesive. Rub it along the edge of the sticker, and see if it lifts up more easily.
If it does, you have found a good solvent. If it doesn’t, it may be rubber-based glue.
In this case, you need something like pine sap remover. There are other solvents, like citrus based ones, but pine sap remover is designed for use on car and won’t damage the finish.
Experiment with the pine sap remover, and if it works along the edge, you’ve found your solvent.
One you know the solvent, cut up the sticker by cutting a few lines across its face, with a razor blade. Then, using a rag or cotton ball, rub the fluid over the lines.
Let it sit a few minutes, and repeat. You’re getting the stuff to soak underneath the sticker.
Keep trying to pull up the sticker. If it doesn’t relent, soak it some more, and wait. The liquid has to get sucked up by the adhesive to work, and that takes time.