Compression seals prevent leakage between two objects under pressure. They fill in irregularities and prevent gases or fluids from escaping. Materials like asbestos are no longer used in the US. The best gasket thickness compensates for surface irregularities and is compressible. Overtightening can ruin sealing qualities, especially for metal gaskets like cylinder head gaskets. Auto manufacturers post the correct torque pressure to avoid overtightening.
A compression seal is a preformed piece of material designed to fit between two objects and prevent leakage under pressure. Commonly located between two surfaces that are bolted together, a compression gasket fills in the irregularities between the mating surfaces. Typically, it also prevents gases or fluids from escaping through tiny spaces or openings where surfaces are not perfectly smooth and seamless. Compression gaskets are commonly made from materials such as rubber, neoprene, graphite, silicone, felt, metal, or plastic.
At one time, compression gaskets were often made from materials that contained asbestos. Because asbestos has been shown to contribute to the deadly lung disease of asbestosis, materials that contain asbestos are no longer used in the manufacture of gaskets of any kind in the United States (USA). Asbestos materials are still used in the manufacture of gaskets, however, in other parts of the world.
A properly functioning compression gasket generally should not be made of material that is too thick. Generally, a thicker gasket is more likely to allow leakage through the pores of the gasket. The best gasket thickness is thick enough to compensate for any surface irregularities and still be compressible.
While some types of gasket materials cannot be overtightened, primarily elastomer or rubber-based materials, other gasket materials, such as metal or Teflon®, can be overtightened, which can ruin their sealing qualities. Metal compression gaskets typically need to have the ability to bounce back or expand in order to function properly. If overtightened, a metal compression gasket will lose this recoverability and be unable to provide a seal.
A perfect example of the need for proper clamping pressure on a metal gasket is the cylinder head gasket installed on the engine in virtually all vehicles. Designed to provide a seal between the engine block and cylinder head, the cylinder head gasket is commonly made from metal. Auto manufacturers usually post the correct torque pressure a mechanic should apply to the bolts that hold the engine together. This helps mechanics replace the head gaskets on an engine without overtightening the bolts, which can ruin the gasket.
Protect your devices with Threat Protection by NordVPN
