Cork is a natural, impermeable and buoyant material harvested for commercial use primarily from the cork oak native to southwest Europe and northwest Africa. Probably best known as the barrier between the wine buff and a bottle’s contents, cork makes comparatively inexpensive, lightweight oil-resistant seals. Its noise and vibration reduction properties are beneficial in diverse environments. Gaskets are manufactured using rubber-bonded cork. The size of the granules and the bonding agents used will determine the type of gasket and its temperature and pressure ratings but, due to its ability to resist oil, cork gaskets are commonly seen in the automotive industry. Other uses include door and window insulation and air and refrigeration compressors.

What is felt? Wool! When compressed to a uniform density, wool becomes felt although synthetic resources such as nylon can also be used either instead of or combined with wool. Felt provides a surprisingly resilient, compliant gasket material.

Under pressure, wool fibres move together and become entangled; unlike woven fabrics, therefore, felt doesn’t fray or unravel. It is most often used to reduce noise or vibration. The higher the felt’s density, the more effective it will prove. Due to its strength and insulation and flame retardant properties, felt is a frequent feature in filtration, polishing and fluid reservoirs.

Due to its carcinogenic properties, asbestos has been wholly banned since 1999 in the UK, although some forms were prohibited as early as 1985. Its extreme effectiveness as a gasket material, especially at high temperatures, left a substantial deficit. 

Fittingly, non-asbestos or asbestos-free gaskets fill the void their hazardous predecessors left behind, performing similar functions without the accompanying harm. 

They are typically formed from fibreglass, aramid fibre, Kevlar, mineral fibre or carbon and, in the same way asbestos came in multiple grades and could be combined with various rubber compounds, so do non-asbestos materials. Optimum material specification will depend on size, temperature, pressure, speed and medium requirements.

How can paper gaskets work? Fundamentally because they’re made from various flexible, robust materials none of which is paper. Paper gaskets are so called because their manufacturing process is comparable to the method by which paper machines take pulp and use it to form sheets of paper. It is also know as gasket sheeting.

Often made from treated cellulose fibre, paper gaskets or sheets enable components to be cut in high volumes quickly and cost effectively. They’re widely used in low temperature and medium pressure environments and have very good oil, fuel, water, alcohol and grease resistance. Their chemical resistance is poor.

Common applications include:

• Oil, fuel and water pumps 

• Carburettors 

• Oil filters