Which material is rarely used as an exhaust vent for oil combustion gases due to their temperature?

Aluminum is rarely used as an exhaust vent for oil combustion gases primarily due to its lower melting point compared to other materials. Oil combustion can produce high temperatures that could easily surpass the limits of aluminum, leading to risks such as warping, melting, or even failure of the vent system.

In contrast, materials like galvanized steel and steel are commonly used in this application because they can withstand higher temperatures without deteriorating. Copper, while also durable and capable of handling heat, is not a standard choice for exhaust vents due to factors like cost and the potential for corrosive reactions with certain combustion gases. Therefore, the use of aluminum for exhaust venting in oil combustion applications poses significant risks, making it an unsuitable choice.