What is a Gasket?
Gaskets are sealing components that are placed between two connecting objects to prevent fluid leakage and improve performance.
They are particularly beneficial when the two objects are under compression, as the gasket can store excess energy like a spring.
Furthermore, they also enable the connection of two irregularly-sized objects by accommodating the size difference between them.
Gaskets can be made from a variety of materials, depending on their application, ranging from metals, composites, rubber, foam, copper, cork and paper.
They are commonly used in pipes, engines, pumps, food-processing equipment, power equipment, mining machinery, filtration systems, aerospace components, boats, trains and many more applications.
Types of Gaskets
Different types of gaskets include:
- Envelope gaskets
- Rubber sheet material gaskets
- Compressor gaskets
- Camlock gaskets
- Spiral wound gaskets – with inner ring
- EGR valve gaskets
- Flat metal gaskets
- FDA gaskets
- IDF gaskets
- Ring-type joint gaskets
- Corrugated metal gaskets
- Manway gaskets
The type of gasket used for an application is dependent on the material’s resistance to chemicals, corrosion, temperature, pressure, gases, acids and electromagnetic forces.
The Importance of Sealing Gaskets
The effective sealing of gaskets can prevent damage and premature failure which can manifest as a result of:
- Uneven compression: asymmetric compression, caused as a result of the working conditions, human error or asymmetric forces, can result in a reduction of the efficacy of gaskets. Sealing gaskets can ensure that they handle uneven compression more effectively.
- Large gaps: if the flanges are particularly uneven, there could be large gaps left that the gasket doesn’t cover. In this case, using a sealant to fully fill the gaps improves the function of the gasket, preventing leaks and damage to performance.
- Rough surfaces: flanges with rough surfaces can mean that existing gaps, as a result of the roughness, aren’t fully covered by the gasket. Sealing can fill these gaps, improving performance.
- Torque loss: excess vibrations, temperature fluctuations and other external forces can result in a loss of torque. Effective sealing can prevent this by providing more structural integrity.
Top Sealants for Gaskets
Benefits of using sealants for gaskets include:
- Ability to sustain extreme temperatures and thermal changes
- Ability to sustain high pressures changes
- Reduced wear and friction – long-term protection
- Gap-filling properties
- Resistance to harsh chemicals, steam, and moisture
- Non-corrosive to metals
- Extended life due to low volatility and outgassing
- Non-damaging to plastic or elastomers – broad elastomeric compatibility
- Non-hazardous and non-toxic
- Minimal environmental footprint; no damage to the atmosphere or ozone layer
Here we explore the top sealants for gaskets:
Silastic RBL-9694-45M is a two-part liquid silicone rubber that can be used for the compression sealing of gaskets in automotive and industrial parts. Its applications include gaskets for components that require high clamping forces such as cam covers, water pumps, ABS modules and thermostat housings. It provides high tear resistance and long-term stability over a wide temperature of -50°C to +200°C. In addition, it offers good adhesion on a variety of substrates.
DOWSIL 7091 is a silicone sealant and adhesive that can be used for the sealing of gaskets without on-line pressure check. It is used as a formed-in-place gasket (FIPG) material and is stable and flexible from -55°C (-67°C) to +180°C (+356°C). This sealant is commonly used on materials such as aluminium, glass, ceramic, enamelled and painted steel, and certain plastics used in engineering applications.
DOWSIL Q3-1566 is a high-temperature-resistant silicone sealant that can be used for the sealing of gaskets without on-line pressure check. It remains flexible and stable from -50 to 275°C and provides good adhesion to a wide range of substrates. It is easy to apply and non-sagging making it suitable for vertical applications and for filling gaps to create a tight seal.
Bostik AU588 is a UV-reactive cure-in-place gasket solution that delivers high seal performance and exceptional elasticity. It offers reliable durability in high-temperature environments and excellent hydrolysis resistance. Its unique balance of high elongation and high tensile strength ensures that it will not crack even when exposed to high compression ratios.
In addition to sealing, lubrication is also hugely beneficial for gaskets as it protects against corrosion and weathering, improves thermal regulation and improves durability. Our guide on lubrication solutions for rubber gaskets in electric motors explores this further.