Which of the following should not come into contact with alkaline base paint?

Aluminum should not come into contact with alkaline base paint because it can lead to a chemical reaction that deteriorates the aluminum. Alkaline environments can cause corrosion or oxidation of aluminum surfaces, ultimately compromising the integrity and performance of the metal.

In contrast, copper, steel, and plastic are less affected by alkaline paints. Copper is often used in electrical applications because of its resistance to corrosion, while steel can be treated or painted to protect it from corrosion, and plastic is resistant to many chemicals, including alkaline substances. Understanding the material compatibility is essential for ensuring the longevity and durability of the surfaces being painted.