O-Ring 8x3 mm VMQ/MVQ 70 Shore A - Silicone Rubber

O-Ring 8x3 mm VMQ/MVQ 70 Shore A - Silicone Rubber Sealing Ring

O-Ring 8x3 mm VMQ/MVQ 70 Shore A is a circular elastomeric sealing ring made from silicone rubber, designated VMQ or MVQ. It has an 8 mm inside diameter, 3 mm cross-sectional diameter and nominal hardness of 70 Shore A. Its nominal outside diameter is 14 mm. The one-piece circular design provides sealing through controlled elastic compression and is primarily suitable for static sealing arrangements involving compatible media. The manufacturer of this specific product has not been identified.

Technical Specifications - O-Ring 8x3 VMQ/MVQ 70 Shore A

The nominal outside diameter is calculated from the inside diameter and twice the cross-sectional diameter:

14 mm = 8 mm + 2 x 3 mm.

This is a nominal geometric dimension and does not include manufacturing tolerances.

Exact dimensional tolerances, operating temperature limits, chemical resistance, tensile strength, compression set and permissible operating pressure must be confirmed against the technical documentation for the specific silicone compound.

What Does O-Ring 8x3 VMQ/MVQ 70 Shore A Mean?

The designation identifies the seal dimensions, elastomer material and nominal hardness.

• 8 - inside diameter in millimeters.

• 3 - cross-sectional diameter in millimeters.

• VMQ - standardized designation for silicone rubber.

• MVQ - alternative designation encountered in commercial descriptions of silicone elastomers.

• 70 - nominal hardness value.

• Shore A - hardness measurement scale used for elastomeric materials.

The first dimension refers to the inside diameter, not the outside diameter.

An O-ring measuring 8x3 mm has an 8 mm nominal inside diameter and a 3 mm circular cross-section.

VMQ vs MVQ - Material Designations

VMQ is the standardized designation for a class of silicone rubber elastomers.

MVQ is also encountered in industrial and commercial terminology for silicone rubber.

Both terms are commonly used to identify silicone O-rings, but neither defines the complete compound formulation.

Two VMQ O-rings with identical dimensions and hardness may differ in chemical resistance, mechanical properties, compression set, temperature performance and regulatory approvals.

Matching dimensions, material designations and hardness values do not automatically guarantee complete interchangeability.

Construction and Operating Principle

The 8x3 mm VMQ silicone O-ring is a one-piece elastomeric sealing element with a circular cross-section.

It contains no metal reinforcement, spring or additional sealing lip.

When installed in a correctly designed groove, the O-ring is compressed between two mating surfaces.

This compression generates contact pressure that helps prevent liquids or gases from passing through the sealing interface.

Effective sealing depends on:

• Correct groove dimensions.

• Appropriate cross-sectional compression.

• Groove fill.

• Surface finish of mating components.

• Operating pressure.

• Temperature.

• Chemical compatibility.

• Compression set.

• Extrusion gap dimensions.

• Static or dynamic operating conditions.

Importance of the 3 mm Cross-Section

The cross-sectional diameter is a critical design parameter.

It influences the required groove depth, compression level, contact pressure and available space for elastomer deformation.

An O-ring measuring 8x3 mm is not automatically interchangeable with an 8x2 mm or 8x2.5 mm O-ring.

Although the inside diameter is identical, the different cross-sections require different groove geometries and installation conditions.

Silicone Rubber VMQ 70 Shore A - Material Properties

Flexibility Across a Broad Temperature Range

VMQ silicone rubber is commonly used in sealing applications requiring flexibility at low temperatures and resistance to elevated temperatures.

Compared with many conventional rubber compounds, silicone elastomers can offer favorable temperature-related properties.

However, the exact permissible operating temperature range depends on the compound formulation, exposure duration, sealed medium and mechanical conditions.

Specific temperature limits should not be assigned without verified material documentation.

Hardness of 70 Shore A

A nominal hardness of 70 Shore A describes the elastomer's resistance to indentation.

Hardness influences:

• Deformation during installation.

• Contact pressure.

• Required compression.

• Resistance to extrusion.

• Mechanical behavior under load.

Hardness alone does not establish the maximum permissible operating pressure.

Pressure capability depends on groove geometry, extrusion gap, temperature, compound properties and the complete sealing arrangement.

Chemical Compatibility

VMQ silicone rubber is not universally resistant to all chemicals.

Before installation, compatibility should be checked for:

• Mineral oils.

• Fuels.

• Solvents.

• Industrial chemicals.

• Process fluids.

• Gases.

Chemical resistance also depends on temperature, concentration and exposure duration.

The suitability of the specific silicone formulation must be confirmed for the intended medium.

Mechanical Resistance

Silicone rubber may have lower resistance to tearing and abrasion than elastomers specifically selected for intensive dynamic sealing.

For this reason, careful handling is important during installation.

Avoid excessive stretching, twisting and dragging the O-ring across sharp edges.

VMQ vs NBR, FKM and EPDM O-Rings

These materials may all be available as O-rings with dimensions of 8x3 mm and nominal hardness of 70 Shore A.

However, they are not automatically interchangeable.

The correct elastomer must be selected according to the sealed medium, temperature, pressure and operating conditions.

Alternative Designations and Search References

The product may appear under the following commercial designations:

• O-Ring 8x3 VMQ 70 Shore A

• O-Ring 8x3 MVQ 70 Shore A

• Silicone O-Ring 8x3 mm

• VMQ O-Ring 8x3 mm

• MVQ Silicone O-Ring 8x3

• O-Ring 8x3 70 ShA Silicone

• Silicone Rubber O-Ring 8x3 mm

• Silicone Sealing Ring 8x3 mm

• O-Ring 8 mm ID x 3 mm CS

These are alternative commercial descriptions of the same nominal dimensions and material category.

They are not verified OEM part numbers or manufacturer-specific cross-references.

Selecting the Correct 8x3 mm Silicone O-Ring

Before ordering, verify the following parameters:

• Inside diameter: 8 mm.

• Cross-sectional diameter: 3 mm.

• Nominal outside diameter: 14 mm.

• Material: VMQ / MVQ silicone rubber.

• Nominal hardness: 70 Shore A.

• Groove dimensions and tolerances.

• Required cross-sectional compression.

• Installation stretch.

• Groove fill.

• Operating pressure.

• Operating temperature.

• Chemical compatibility.

• Static or dynamic sealing conditions.

• Surface finish.

• Extrusion gap.

• Required service life.

How Should the Groove Be Designed?

The groove must provide sufficient compression to create an effective seal while allowing space for elastomer deformation.

The groove depth should not simply be assumed to equal the 3 mm cross-sectional diameter.

Insufficient compression may cause leakage, while excessive compression may damage the elastomer or accelerate permanent deformation.

Groove dimensions should be selected according to the sealing arrangement and applicable engineering design guidelines.

What Is the Outside Diameter of an 8x3 mm O-Ring?

The nominal outside diameter is 14 mm.

It is calculated by adding twice the 3 mm cross-sectional diameter to the 8 mm inside diameter.

This value refers to the uninstalled, undeformed O-ring and does not include manufacturing tolerances.

Typical Applications of Silicone O-Rings

Small-diameter VMQ silicone O-rings can be used in compact sealing arrangements where the material and geometry are compatible with operating conditions.

Typical applications of this sealing design include:

• Static joints in industrial equipment.

• Small covers and housings.

• Compact technical assemblies.

• Connections requiring elastomeric sealing rings.

• Mechanical components with correctly designed O-ring grooves.

These are general applications of silicone O-ring technology, not verified OEM applications for this specific product.

Food, Medical and Drinking Water Applications

Silicone rubber is used in certain food-contact, medical and drinking-water applications.

However, the VMQ material designation alone does not establish regulatory compliance.

Suitability for these applications requires appropriate documentation for the specific silicone compound and finished product.

A generic silicone O-ring should not be described as food-grade, medical-grade or drinking-water approved without verified certification.

Installation and Maintenance

Preparing the Sealing Surfaces

Before installation, clean the groove and mating surfaces.

Remove dirt, burrs and sharp edges that could damage the silicone elastomer.

Inspect the groove for scratches, corrosion and dimensional defects.

Installing the O-Ring

During installation:

• Position the O-ring evenly inside the groove.

• Avoid twisting the elastomer.

• Do not stretch the ring more than necessary.

• Avoid sharp installation tools.

• Use only assembly lubricants compatible with silicone and the sealed medium.

• Check that the O-ring is not trapped or pinched between mating components.

Inspection During Service

Inspect the sealing arrangement during scheduled maintenance.

Replace the O-ring if it shows cracking, tearing, permanent flattening, excessive swelling or loss of elasticity.

Storage

Store silicone O-rings in a clean, dry environment.

Protect them against contamination, mechanical damage, excessive stretching and permanent compression.

Frequently Asked Questions - O-Ring 8x3 VMQ/MVQ 70 Shore A

1. What are the dimensions of the 8x3 mm silicone O-ring?

The O-ring has a nominal inside diameter of 8 mm, cross-sectional diameter of 3 mm and outside diameter of 14 mm.

2. What does VMQ or MVQ mean?

VMQ is the standardized designation for silicone rubber. MVQ is an alternative designation encountered in industrial sealing terminology.

3. What does 70 Shore A mean?

70 Shore A indicates the nominal hardness of the silicone elastomer. It describes resistance to indentation but does not independently determine maximum operating pressure.

4. Is the 8x3 mm silicone O-ring resistant to high temperatures?

VMQ silicone rubber is commonly used in applications requiring flexibility across a broad temperature range. Exact operating temperature limits depend on the specific compound.

5. Can an 8x3 mm VMQ O-ring replace an NBR O-ring?

Not automatically. VMQ and NBR differ in chemical, thermal and mechanical properties. Material compatibility must be verified before substitution.

6. Is this silicone O-ring suitable for food contact?

Not without appropriate documentation. Food-contact suitability requires verification of the specific silicone compound and finished product.

7. Can the 8x3 mm VMQ O-ring be used in dynamic sealing applications?

Suitability depends on movement, friction, lubrication, pressure and compound properties. Silicone may have limited abrasion resistance, so dynamic applications require careful evaluation.

8. Does 8x3 mean the outside diameter is 8 mm?

No. The first dimension is the inside diameter, while the second is the cross-sectional diameter. The nominal outside diameter is 14 mm.

O-Ring 8x3 VMQ/MVQ 70 Shore A - Key Product Information

The 8x3 mm VMQ/MVQ 70 Shore A O-ring is a silicone rubber sealing ring with an 8 mm inside diameter, 3 mm circular cross-section and 14 mm nominal outside diameter. Its nominal hardness is 70 Shore A. Designed primarily for compatible static sealing arrangements, it requires correct groove dimensions, controlled compression and verification of chemical and temperature compatibility.

The 8x3 mm VMQ/MVQ 70 Shore A silicone O-ring is offered by simmering.pl, an industrial sealing components and bearing supplier operated by TG Ersatzteile Polska Sp. z o.o. The company maintains a warehouse in Lublin, Poland, serving industrial customers, maintenance departments and technical procurement teams with shipping across Europe and worldwide.