Flat gasket

Rubber flat gasket

A rubber flat gasket reliably seals two flat surfaces and reduces leakage with liquids and gases. In industrial applications it is used where defined dimensions, elastic adaptation to the surface and a durable sealing effect are required.

The choice of material determines resistance, temperature range and service life. EPDM (ethylene propylene diene rubber) is particularly suitable for applications involving weather, ozone, ageing and many aqueous media. For material classification and typical use cases, the page EPDM gasket provides a suitable basis.

For technical projects, the rubber flat gasket is often produced as a cut piece to size or to drawing. Dimensional accuracy, thickness and contact pressure are the decisive parameters for reproducible sealing.

EPDM flat gasket: properties, advantages and typical areas of application

EPDM (ethylene propylene diene rubber) is frequently used for flat gaskets where weather, ozone, UV and aqueous media are the main considerations. The material is selected on a practical basis via temperature range, media contact and the required elasticity.

Technical properties

• Material: EPDM (ethylene propylene diene rubber)
• Colour: black
• Hardness: typical range 60–70 Shore A (depending on the compound)
• Density: approx. 1.25 g/cm³
• Temperature range: approx. −40 °C to +120 °C (up to +150 °C depending on the compound)
• Tensile strength: depending on compound and specification
• Elongation: typical guide value approx. 300 % (depending on the compound)

Material properties in application

EPDM offers high resistance to ozone, UV radiation and weathering. In many outdoor applications this ensures a stable sealing effect over long periods of use. The elastic adaptation supports sealing with slight surface structures and customary manufacturing tolerances.

For applications involving mineral oils or fuels, other elastomers such as NBR or FKM are generally suitable; the comparison EPDM vs. NBR vs. silicone provides a quick classification.

Advantages of EPDM flat gaskets

• Weather and ozone resistance: suitable for outdoor areas and changing environments
• Resistance to many aqueous media: suitable for water and sanitary applications
• Thermal stability: reliable under typical temperature fluctuations in operation
• Elasticity: supports uniform sealing across the surface
• Ageing resistance: for long-term applications with constant requirements

Typical areas of application

• Construction and building services: sealing at connections, covers and housings
• Sanitary and heating technology: applications involving water, steam and changing temperatures
• General mechanical and plant engineering: sealing surfaces on housings, covers and interfaces
• Vehicle technology: sealing tasks with a focus on weather and ozone

Further basics on the material and selection criteria can be found on the page EPDM gasket.

Production and specifications of EPDM flat gaskets

EPDM flat gaskets are predominantly produced from prefabricated rubber sheets. Depending on geometry, quantity and tolerance requirement, production is carried out by punching, cutting or waterjet cutting. This approach enables reproducible dimensions and a consistent sealing quality.

Production methods

For series applications with a constant contour, punching is often used. For variable geometries or single pieces, flat gaskets made of EPDM are produced as cut pieces to size. Waterjet cutting is particularly suitable for complex contours and tight dimensional tolerances.

Thicknesses and dimensional tolerances

EPDM flat gaskets are available in various thicknesses. Usual material thicknesses are between 1 mm and 10 mm, depending on contact pressure and gap dimension. The choice of thickness directly influences the sealing effect as well as the required screw force.

For technical applications, defined dimensional tolerances are taken into account. A clean coordination between gasket thickness, surface condition and surface pressure ensures uniform sealing.

Design to size or drawing

In practice, EPDM flat gaskets are frequently produced to customer specifications. The basis is either a fixed dimension or a technical drawing. Information on material, thickness and operating conditions is decisive for the design.

For individual solutions, the cutting of rubber gaskets offers a flexible option for a precisely fitting implementation.

EPDM compared with NBR, silicone and FKM

The selection of the suitable gasket material depends on the medium, temperature range and ambient conditions. EPDM is preferably used where weather resistance and resistance to water or steam are required. In other applications, alternative elastomers are used.

EPDM

EPDM is suitable for applications involving water, steam, ozone, UV radiation and changing weather conditions. The material offers good elasticity and ageing resistance at moderate temperatures.

NBR

NBR is used where there is contact with oils, greases or fuels. The material offers good mechanical load capacity and is frequently used in mechanical engineering and hydraulics.

Silicone

Silicone flat gaskets are used at very high or very low temperatures. The material is characterised by high temperature stability and physiological safety.

FKM

FKM is used where high temperatures and aggressive chemicals are present. The material is suitable for demanding industrial applications with high requirements for media resistance.

A detailed comparison of the materials supports material selection in individual cases. The comparison EPDM vs. NBR vs. silicone provides a structured basis for decision-making.

Frequently asked questions about flat gaskets

What are flat gaskets?

Flat gaskets are gaskets with a flat geometry, usually round or rectangular. They seal connections between flat surfaces and prevent the escape of liquids or gases.

What are flat gaskets made of?

Flat gaskets are made of various materials such as rubber, cork, paper, metal or technical elastomers. The choice of material depends on the medium, temperature and mechanical load.

Where are flat gaskets used?

Flat gaskets are used in mechanical engineering, in the automotive industry, in sanitary and heating systems as well as in the chemical and process industry, in particular on flanges, covers and housings.

How are flat gaskets installed?

The flat gasket is inserted between the surfaces to be connected and evenly compressed by tightening the bolted connection. Clean contact surfaces and defined screw forces support reliable sealing.

How do you select the right material for flat gaskets?

The decisive factors are temperature range, pressure, media contact and ambient conditions. Elastomers such as EPDM are suitable for water and weather, NBR for oil and grease, FKM for high temperatures and chemicals.

Can flat gaskets be reused?

In practice, flat gaskets are replaced after dismantling, as deformation or material fatigue can affect the sealing effect.

How do you maintain flat gaskets?

Before installation, the gasket and sealing surfaces should be clean, dry and free from damage. Contamination or notches can impair the seal.

How long do flat gaskets last?

The service life depends on the material, the operating conditions and the mechanical load. With a suitable choice of material and correct installation, several years of use are customary.

What are common causes of flat gasket failure?

Typical causes are incorrect material selection, uneven surface pressure, overload, ageing of the material or damaged sealing surfaces.

How can the tightness of flat gaskets be checked?

Tightness is checked by pressure tests, visual inspections for leakage or application-specific test methods.

Are flat gaskets suitable for different temperatures?

Depending on the material, flat gaskets cover different temperature ranges. Elastomers such as EPDM are suitable for moderate temperatures, silicone for high or very low temperatures.

How are flat gaskets dimensioned?

Dimensioning is carried out via the outer and inner diameter or length and width as well as the thickness. The dimensions must match the geometry of the surfaces to be sealed.

Can flat gaskets be cut to size yourself?

Flat gaskets can be cut from sheet material. For technical applications with tolerance requirements, professional cutting to size offers greater dimensional accuracy.

Individual solutions can be implemented via the cutting of rubber gaskets.