Gaskets & O-Rings

Gaskets and O-rings are essential sealing components used to join two parts of a machine, engine, or another mechanical assembly. They function by filling the space between the two mating surfaces, creating a sealed barrier. This seal serves the crucial purpose of preventing the ingress or leakage of particles, vapour, and fluids, protecting and maintaining the integrity of the joint or pressure. Additionally, they keep debris out, ensuring proper function and safety. Rubber gaskets and rubber O-rings are commonly used in various fields and industries, including automotive, aerospace, and general engineering.

RS New Zealand supplies a great range of gaskets and seals, including nitrile O-rings which have great resistance to abrasion and can be used for various sealing applications. Our nitrile O-rings are available in both metric and imperial standard sizes. Imperial sizes are usually to BS1806, and Metric sizes are to BS4518. You can see more in our Gaskets and O-rings guide.

How Do Rubber Gaskets and O-rings Work?

A gasket or O-ring is seated between two parts, often in a groove in one of the two parts to be joined, then compressed between these two components to the corresponding groove creating a securely sealed joint. This compression causes the rubber gasket or O-ring material to deform slightly, effectively filling any microscopic irregularities or gaps on the mating surfaces of the components. The elasticity of the rubber O-rings and other materials ensures that the seal remains effective even under varying pressures and temperatures. They can be used in dynamic joints where there is movement, such as in pumps or hydraulic cylinders, as well as in static or fixed applications, like sealing flanges or housings.

Types of Rubber Gaskets

Flat Gaskets

Flat gaskets are a fundamental sealing solution, typically manufactured from sheet materials like rubber, cork, or fibre. These rubber gaskets are versatile and cost-effective, providing a seal between two static surfaces when compressed. They are widely used in various applications, from plumbing and HVAC to general machinery, to prevent leaks of liquids or gases.

Spiral Wound Gaskets

Spiral wound gaskets are engineered for demanding applications involving high pressures and temperatures. Constructed from alternating layers of a metallic winding and a softer filler material, such as graphite or PTFE, these rubber gaskets offer excellent resilience and sealing integrity in pipelines, heat exchangers, and other critical systems.

Ring Joint Gaskets (RTJ)

Ring Joint Gaskets (RTJ) are robust, high-integrity metallic seals designed for extreme pressure and temperature services. These rubber gaskets are typically used in the oil and gas industry, as well as in high-pressure piping and vessel applications, where a reliable and leak-free seal is paramount under severe operating conditions.

Kammprofile Gaskets

Kammprofile gaskets feature a metallic core with concentric serrations or grooves on each face, often with a soft facing layer of graphite or PTFE. This design provides excellent sealing performance, even under fluctuating temperatures and pressures. They are commonly used in chemical processing, power generation, and refining industries.

Fishbone Gaskets

Fishbone gaskets, also known as tanged gaskets, consist of a metallic core with a toothed or "fishbone" pattern that enhances the mechanical grip on the sealing faces. Combined with a soft sealing material, they offer good performance under high temperatures and pressures and are often used in applications like exhaust systems and cylinder heads.

Types of O-Rings

Standard O-Rings

Standard O-rings are toroidal-shaped seals, renowned for their simplicity and effectiveness in both static and dynamic sealing applications. Their versatility makes them one of the most widely used sealing solutions across various industries. O-rings in NZ are available in a multitude of materials and sizes to suit diverse needs. Common materials include:

• Nitrile Rubber (NBR): Known for its excellent resistance to oils, fuels, and hydraulic fluids. These rubber O-rings are a cost-effective and widely used option.
• EPDM: Offers superior resistance to weathering, ozone, and UV exposure, making it suitable for outdoor applications.
• FKM (Viton®): Provides exceptional resistance to high temperatures and a broad range of chemicals.
• Silicone: Exhibits a wide operating temperature range and good flexibility, often used in food and medical applications. Silicone O-ring options are readily available.

Standard O-rings are available in a comprehensive range of metric and imperial sizes to meet various sealing requirements.

Quad Rings (X-Rings)

Quad rings, also known as X-rings, feature a four-lobed design that provides enhanced sealing performance compared to standard O-rings. Their unique shape offers a larger sealing surface and reduces the tendency to roll or twist in the groove, making them ideal for dynamic applications in hydraulic and pneumatic systems.

Encapsulated O-Rings

Encapsulated O-rings consist of an elastomeric core (such as silicone or Viton®) that is fully encapsulated in a chemically inert material like PTFE or FEP. This design combines the resilience of the elastomeric core with the exceptional chemical resistance of the encapsulating layer, making them suitable for use in aggressive chemical environments where standard rubber ring or plastic O-rings may not be sufficient.

Key Considerations When Selecting Rubber Gaskets and O-Rings

Choosing the correct gasket or O-ring is crucial for ensuring a reliable and leak-free seal in your application. Several key factors should be carefully considered to match the specific requirements:

• Temperature Range: Consider the minimum and maximum operating temperatures of the application. Different materials, such as silicone O-ring options for high temperatures or specific rubber O-rings for low temperatures, have varying temperature tolerances that must be matched to the environment.
• Chemical Compatibility: Determine the fluids or gases that the gasket or O-ring will come into contact with. Selecting a material that is chemically compatible with these substances is essential to prevent degradation, swelling, or failure of the seal. This is a key consideration when choosing between different types of rubber gasket materials, as well as plastic O-rings.
• Pressure Conditions: Evaluate the pressure that the gasket or O-ring will need to withstand. Different materials and designs are suitable for various pressure levels. For high-pressure applications, reinforced or specialised O-rings may be necessary.
• Mechanical Requirements: Consider the mechanical stresses and movements involved in the application. This includes factors like compression force, abrasion resistance (especially important in dynamic applications for o rubber ring types), and whether the seal will be static (between stationary parts) or dynamic (between moving parts).
• Size and Dimensions: Ensure that the gasket or O-ring has the correct inner diameter, outer diameter, and thickness or cross-section to fit properly within the designated space and create an effective seal. Both metric and imperial sizes are available for various applications.
• Material Type: Select the appropriate material based on the combination of the above factors. Common materials include various types of rubber (like nitrile, EPDM, neoprene), silicone, fluorocarbon (Viton®), and plastic (plastic O-rings), each offering different properties and resistances.
• Industry Standards and Certifications: Depending on the industry (e.g., food, medical, automotive), specific standards and certifications may be required. Ensure that the selected rubber gaskets and O-rings meet these necessary regulations.
• Cost and Availability: Consider the overall cost of the gasket or O-ring material and the ease of availability, particularly for ongoing maintenance and replacement needs within the New Zealand market.

Applications of Gaskets and O-Rings

Gaskets and O-rings are indispensable sealing components found in a vast array of industries, ensuring the integrity and performance of countless mechanical systems. Their ability to prevent leaks and maintain pressure makes them critical in diverse applications. Here are some common examples of industries where rubber O-rings, rubber gaskets, and other types of seals are widely used:

• Automotive Industry: In automotive applications, rubber O-rings and rubber gaskets are crucial for sealing various engine components (like cylinder heads and oil pans), hydraulic systems (such as brakes and power steering), fuel systems, and coolant systems, ensuring reliable operation and preventing fluid leaks.
• Aerospace: The aerospace industry relies heavily on high-performance O-rings and gaskets to maintain critical seals in aircraft engines, hydraulic actuators, fuel lines, and hatches. Materials like Viton® are often used due to their exceptional resistance to extreme temperatures and chemicals.
• Chemical and Petrochemical Industry: In environments dealing with corrosive substances, chemically resistant gaskets and O-rings are essential for sealing pipes, valves, pumps, and reactors. Materials like PTFE and specific types of rubber gaskets are chosen for their ability to withstand harsh chemicals and prevent leaks.
• Marine Industry: The marine environment demands seals that can withstand saltwater corrosion and extreme conditions. Rubber O-rings and gaskets made from materials like neoprene and specialised rubber compounds are used in boat engines, underwater equipment, hydraulic systems, and various other marine applications.
• Food and Beverage: Hygiene and safety are paramount in the food and beverage industry. Silicone O-ring options and rubber gaskets made from food-grade materials are used to seal processing equipment, pipelines, and valves, ensuring sanitary conditions and preventing contamination.

Find the Perfect Gaskets and O-Rings for Your Application Today!

RS is a trusted supplier and distributor of quality gaskets and O-rings in NZ, offering a wide selection from leading brands like RS PRO, Hutchinson Le Joint Français, and TE Connectivity. Whether you need durable rubber O-rings for demanding environments, reliable rubber gaskets for industrial use, or specific silicone O-ring or plastic O-rings for specialised applications, find the right sealing solution to meet your needs. Explore our extensive range of rubber gaskets and O-rings available for sale across New Zealand.

Ordering & Delivery Information for NZ

Ordering your gaskets and O-rings from RS NZ is quick and easy. Simply browse our extensive online catalogue, add your chosen rubber O-ring or rubber gasket to your cart, and complete your purchase securely.

We offer next working day delivery for locally stocked items when you order before 5:00pm NZT. Standard delivery across New Zealand typically takes 2–5 business days, with regional areas subject to longer lead times. For more details on our delivery services and fees, please visit our Delivery Information page.