Loctite SI 5910 - Gasket Maker -:300ml

LOCTITE® SI 5910 is a one-component, moisture-cured, thixotropic silicone flange sealant designed primarily for flexible flange applications. It forms a flexible gasket that accommodates joint movement while providing excellent resistance to automotive engine oils. It is particularly suitable for stamped sheet-metal covers, timing covers, oil sumps and similar applications. 

Unlike anaerobic flange sealants, LOCTITE SI 5910 cures through reaction with atmospheric moisture. Its thixotropic consistency helps prevent excessive migration after application and makes it suitable for both manual application and automated dispensing. 

Key Features

Silicone-based flange and gasket sealant

Black colour

One-component formulation — no mixing required

Moisture-cured / RTV silicone

Excellent oil resistance

Designed for flexible flanges

Accommodates joint movement

Thixotropic, non-sagging formulation

Rapid skin-over time

Suitable for gaps up to approximately 1 mm

Cure-through volume of approximately 2.75 mm in 24 hours

Operating temperature: -55°C to +200°C

Suitable for metal and plastic flanges

Available in tube and cartridge packaging. 

Typical Applications

LOCTITE SI 5910 is commonly used for:

Engine oil sumps

Timing covers

Stamped sheet-metal covers

Flexible flange joints

Automotive engine components

Industrial machinery housings

Metal and plastic flange assemblies

Replacement of conventional formed-in-place gaskets

Applications exposed to engine oils and lubricants

Henkel specifically identifies timing covers and oil sumps as typical applications. �

Henkel Datasheets

Oil Resistance

A major advantage of LOCTITE SI 5910 is its excellent resistance to automotive engine oils. This makes it particularly useful for sealing joints in engines and other machinery where the gasket is exposed to oils during service.

Flexible Flange Sealing

LOCTITE SI 5910 is formulated for applications where the mating components can experience joint movement. After curing, the silicone remains flexible rather than forming a rigid adhesive joint. This flexibility helps maintain the seal when the flange experiences thermal expansion, vibration or movement.

How It Cures

LOCTITE SI 5910 is a room-temperature-vulcanizing (RTV) oxime silicone. After application, atmospheric moisture reacts with the silicone, producing a cured elastomeric seal.

The surface becomes tack-free in approximately 40 minutes at 25°C / 50% relative humidity, while complete curing depends on the thickness of the applied material, temperature and humidity. 

Substrate Compatibility

Henkel lists LOCTITE SI 5910 for use with:

Metal

Plastic

Glass

Ceramic

For critical applications, the actual substrate and operating conditions should be evaluated before production use. 

Technical Specifications

Property: LOCTITE SI 5910

Product type: Silicone flange sealant

Technology: Silicone

Chemical type: Oxime silicone

Colour: Black

Components: 1-part

Cure system: Moisture / RTV cure

Appearance: Thixotropic paste

Tack-free time: Approx. 40 minutes

Gap capability: Up to 1 mm

Cure-through volume: Approx. 2.75 mm / 24 h

Operating temperature: -55°C to +200°C

Shore hardness: Approx. 30A

Elongation: ≥400%

Tensile strength: ≥1.7 N/mm²

Main characteristic: Excellent oil resistance

Technical values are based on Henkel's published product information and technical data sheet. 

Advantages of LOCTITE SI 5910

LOCTITE SI 5910 is particularly useful when you need a flexible, oil-resistant gasket seal rather than a rigid bonded joint. Its one-component formulation makes it convenient to dispense, while its thixotropic properties help keep the sealant where it is applied.