The hottest summer ever
Strange phenomenon detected
Vehicle bonnet bulged
Summer is in full swing, and the heat is unrelenting. Some forecasters predict that this could be the hottest summer on record. Indeed, several countries are already reporting damage due to unusual temperature spikes.
In a related phenomenon, bulging vehicle hoods have been spotted in various parts of the world, including some regions of China, sparking widespread curiosity online. It raises the question: Can extreme heat cause an iron plate to deform significantly? We investigated to find out what was happening.
Many were caught in China
It occurs only on wrapped vehicles
According to Chinese social media such as Weibo, this phenomenon began to be observed around mid-April 2024. A BMW 5 Series owner posted a photo of his vehicle with the bonnet swollen into a round dome, saying, “I was just leaving home when I saw my vehicle like this.” He was confused, saying, “I’m afraid that it will explode if I touch it even slightly.” And he asked, “What should I do?”
This strange sight was recently captured in other parts of China and spread worldwide. According to local media reports, this phenomenon occurred in Hubei Province, China, and the wrapping film is said to have swelled due to abnormally high temperatures. There is no need to worry about vehicles in original condition. Still, expansion may occur in vehicles that have been covered with a separate film or that have been subjected to a process commonly referred to as wrapping.
Phenomena caused by chemical reactions
Vehicles that have just been wrapped are at risk
Wrapping is a tuning process that applies a flexible film with a color or pattern to the car body, and it is not difficult to see wrapped vehicles. In the case of wrapping, it has the advantage that the construction period is shorter than full painting and that the film can be peeled off at any time to return it to its original state. The cost is cheaper than painting, making it popular among those who want to change their car color with less burden. So, what is the principle behind forming such a large air layer underneath the film firmly attached to the car body?
According to industry officials, soapy water is first sprinkled on the car body surface to facilitate the attachment of the film during wrapping work. At this time, glycerin is sometimes mixed to delay the drying time of the soapy water, but it is said that this ingredient can be problematic. When the vehicle surface gets hot, glycerin vaporizes between the adhesive surfaces, increasing the volume by up to 1,500 times. The glycerin component is removed in vehicles that have been wrapped for a certain period. Still, this phenomenon may occur in cars that have been recently wrapped, depending on the temperature.
It is also used for film removal
How to prevent swelling?
Once a vehicle wrap has swelled, it is beyond saving. The film has stretched past its elastic limit and lost its adhesive strength, making it impossible to reattach appropriately. Unfortunately, the only solution is to replace it, which can be costly—potentially running into thousands of dollars. When customers want to remove a wrap, some companies resort to drilling a small hole in the film and injecting high-temperature compressed air to peel it off the car body. Re-wrapping, although expensive, becomes inevitable.
Therefore, if you are seriously planning to wrap your vehicle, avoiding the summer season as much as possible would be wise. If you have already done the wrapping without knowing this, the best way is to park in a cool place where you can avoid sunlight, such as a shady spot in a parking lot or an underground parking lot, for a while.
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