How Long Can Toothpaste on Rearview Mirrors Repel Rainwater?
2 Answers
Applying toothpaste on rearview mirrors can repel rainwater for about one to two hours. The effectiveness of toothpaste in preventing rain and other rain prevention methods are as follows: Effectiveness of Toothpaste in Preventing Rain: Toothpaste applied to rearview mirrors can repel rain because it disrupts the surface tension of water. When water hits the mirror, it forms a thin film, maintaining the clarity of the mirror and effectively preventing fogging. Other Rain Prevention Methods: In addition to applying toothpaste, waterproof films can be installed on rearview mirrors. These films have excellent hydrophobic properties, effectively preventing rainwater from adhering. High-quality films not only repel water but also offer anti-fog, anti-dust, and anti-fingerprint functions, ensuring the mirror remains clear.
I once tried applying toothpaste to the rearview mirror on a rainy day, having heard it could prevent water droplets from sticking. The result showed that toothpaste did help water beads roll off quickly, but the effect was short-lived, lasting only through one or two rainfalls or about a day. This is because the fluoride in toothpaste forms a temporary hydrophobic layer, which gets washed away quickly by rain and sunlight, especially during heavy rain or high-speed driving. I recommend not relying on this method to avoid the danger of blurred vision. It’s more practical to keep a dedicated rain-repellent spray in the car, or temporarily use a diluted solution of dish soap and water as a quick fix. Remember to clean the rearview mirror surface regularly to avoid toothpaste residue affecting visibility—after all, driving safety comes first.
