Red Seal Industrial Mechanic (Millwright) Practice Exam

Which of the following materials is most commonly used for making gaskets?

1. Metal

2. Rubber, cork, or paper

3. Plastic

4. Glass

The correct answer is: Rubber, cork, or paper

The most commonly used materials for making gaskets are rubber, cork, or paper. These materials are favored due to their excellent sealing properties, flexibility, and ability to compress under pressure, which helps form a tight seal between two surfaces. Rubber gaskets are particularly valued for their resilience and durability, making them ideal for various applications, including sealing in engines and piping systems. Cork is often used because of its compressibility and resistance to wear, while paper gaskets are typically utilized in lower-pressure applications, like in small engines or appliances. Metal, while used in some specialized gaskets, is generally not as effective for standard applications due to its rigidity and potential to deform under pressure. Plastic is also used, but it's less common than the other materials mentioned, particularly in high-temperature and high-pressure scenarios. Glass is not a suitable material for making gaskets, as it lacks the necessary flexibility and sealing capabilities. Thus, the combination of rubber, cork, and paper makes option B the most appropriate choice for common gasket-making materials.