Cast aluminum is a durable metal widely used in outdoor settings, particularly for furniture and decorative items. The answer to whether cast aluminum gets hot in the sun is yes; its surface temperature can significantly exceed the surrounding air temperature. This heating is a direct consequence of the material’s inherent characteristics combined with the intensity of solar radiation.
The Thermal Properties of Cast Aluminum
Cast aluminum heats up rapidly due to two primary material science concepts: high thermal conductivity and a relatively low specific heat capacity. Aluminum is an excellent heat conductor, meaning that solar energy absorbed on the surface is quickly distributed throughout the entire object, leading to a uniform temperature increase.
Specific heat capacity refers to the amount of energy required to raise a material’s temperature by a certain degree. Cast aluminum has a lower specific heat capacity compared to materials like water or wood, requiring less solar energy to cause a significant temperature jump. This combination of properties results in the metal quickly becoming hot to the touch under direct sunlight. This high conductivity also means the metal will dissipate its heat quickly once it is moved into the shade or the sun is blocked.
External Factors Affecting Surface Temperature
The actual surface temperature of cast aluminum furniture is heavily influenced by external environmental variables. The most noticeable factor is the color and finish applied to the metal. Darker finishes, such as black or dark bronze powder coatings, absorb a greater percentage of the sun’s radiative energy. This causes their surface temperature to climb faster and reach higher peaks, sometimes exceeding 70 degrees Celsius (158 degrees Fahrenheit) under intense sun exposure.
Ambient air temperature also plays a role, as a higher starting temperature contributes to a higher final surface temperature. Furthermore, the duration and angle of sun exposure are significant. Direct, midday sun transfers the maximum amount of energy to the metal’s surface, while indirect or morning sun has a less pronounced heating effect. The proximity of the furniture to heat-retaining surfaces, such as stone patios or dark concrete, can also increase the surrounding microclimate temperature.
Practical Strategies for Managing Heat
Since cast aluminum can reach temperatures high enough to cause contact burns, especially for young children and pets, managing its surface heat is important. One effective long-term mitigation technique involves strategic placement in shaded areas. Using structures like pergolas, awnings, or large umbrellas shields the furniture from direct solar radiation, preventing heat buildup.
For furniture that must remain in the sun, utilizing accessories provides a simple barrier. Applying protective covers or using thick cushions creates an insulator between the hot metal and the skin. Choosing cushions and covers with light colors is also beneficial, as lighter fabrics reflect more solar energy, further reducing heat absorption.
In situations where the metal is already hot and needs quick, temporary cooling, spraying the surface with water from a hose is a short-term solution. This method provides immediate relief through evaporative cooling, though the effect is temporary if the furniture remains in direct sun. To prevent temperature spikes, consider moving existing dark-colored pieces into the shade or applying a lighter-colored, UV-resistant paint to the surface.