Why Add Gasoline When Painting?
3 Answers
Because paint is a viscous oily pigment that is flammable when wet, insoluble in water, slightly soluble in fats, and soluble in alcohols, aldehydes, ethers, benzene, and alkanes, while being highly soluble in gasoline, kerosene, and diesel. Therefore, paint can be washed off with gasoline. Below is relevant information: Decorative Functions of Paint: Color, gloss, patterns, and smoothness. Applying paint to objects of different materials can result in vibrant and colorful appearances, playing a role in beautifying the human living environment and making a significant contribution to both material and spiritual life. Gasoline: Gasoline is a volatile, flammable hydrocarbon mixture liquid obtained from the distillation and cracking of petroleum, used as fuel. It appears as a transparent liquid, is combustible, with a distillation range of 30 to 220 degrees Celsius, and mainly consists of C5 to C12 aliphatic hydrocarbons and cycloalkanes.
Using gasoline to thin paint is actually an old practice. Gasoline can dissolve the resin in oil-based paint, making the paint thinner and easier to apply. Back in the day, experienced mechanics in repair shops often did this since gasoline was cheap and readily available. However, gasoline evaporates too quickly—before the paint even dries properly—leading to issues like bubbling and cracking in the coating. It can also corrode plastic parts. Nowadays, specialized thinners are used instead. For example, turpentine is used for alkyd paint, and lacquer thinner (banana oil) for nitrocellulose paint. These dry more evenly and don’t damage the car. Most importantly, they’re much safer—gasoline can ignite with just a spark. I witnessed a paint-mixing bucket catch fire when I was younger.
Adding gasoline to paint is quite risky. The reason gasoline can be used as a thinner is mainly because both gasoline and paint are organic compounds, which can dissolve each other, making the paint smoother to apply. However, the issue is that gasoline has a very low flash point—it can evaporate at temperatures as low as -20°C, filling the entire workshop with flammable vapors during spraying. When I worked at an auto repair shop, a worker tried to save money by using gasoline to thin paint. A spark from a grinder ignited the entire bucket of paint, nearly blowing up the paint booth. Nowadays, professional shops use dedicated thinners. Although they are more expensive, they are much safer and don’t have such a pungent odor.
