Sikaflex®-291i Marine Adhesive Sealant – 300 ml Black

Multipurpose Polyurethane Sealant for Boats, Yachts and Marine Repairs

Sikaflex®-291i is a one-component, moisture-curing polyurethane sealant developed specifically for the marine market. Supplied in a 300 ml black cartridge, it is designed for flexible, vibration-resistant joint sealing and a range of interior and exterior sealing applications in marine construction.

The product forms a flexible elastomer as it cures and has good non-sag properties, helping it stay in position during application. It adheres to a range of commonly used marine substrates, including wood, metals, suitable metal primers and paint coatings, ceramics and glass-reinforced plastic (GRP), subject to proper surface preparation and compatibility testing.

Sikaflex®-291i is also paintable, non-corrosive and described by Sika as solvent-free with very low VOC and low odour. It is Wheelmark approved and meets the manufacturer’s stated low-flame-spread requirements for marine applications.

Key Features and Benefits

1. Designed for Marine Sealing

Developed for marine construction and maintenance, Sikaflex®-291i is suitable for making elastic, vibration-resistant joint seals in compatible boat and yacht applications.

2. Flexible Polyurethane Sealant

Its moisture-curing polyurethane chemistry forms a flexible elastomer. This flexibility is useful in suitable joints that experience movement and vibration during normal service.

3. Good Non-Sag Properties

The product is formulated to maintain its position during application, helping with sealing work on suitable vertical or inclined surfaces.

4. Bonds to Common Marine Substrates

Sika identifies wood, metals, metal primers, two-component paint coatings, ceramic materials and GRP among the compatible substrate types. Surface preparation and adhesion testing remain essential.

5. Paintable Finish

The cured sealant can be overpainted where the paint system is compatible. Follow the manufacturer’s instructions for paint compatibility and timing.

6. Non-Corrosive Formulation

Sika identifies non-corrosive properties as a product benefit, which can be relevant when sealing compatible marine assemblies. Always verify compatibility with the actual materials involved.

7. Solvent-Free and Very Low VOC

The manufacturer’s product documentation describes Sikaflex®-291i as solvent-free with very low volatile organic compound (VOC) content. Consult the current Safety Data Sheet for handling and exposure guidance.

8. Convenient 300 ml Cartridge

The cartridge format is suitable for dispensing with compatible application equipment. Confirm gun compatibility before beginning the job.

Recommended Applications

Sikaflex®-291i may be used for suitable sealing work involving:

• Flexible, vibration-resistant joints in marine construction
• Selected interior and exterior sealing applications on boats and yachts
• Sealing joints involving compatible timber components
• Suitable metal and painted-metal joints
• Compatible GRP and ceramic components
• General marine assembly sealing where the product is specified

Important: Sikaflex®-291i is a multipurpose marine adhesive sealant, not a specialised teak-deck caulking product or a universal structural adhesive. Do not assume it is suitable for underwater service, permanent immersion, structural bonding or every exposed exterior joint without checking the manufacturer’s guidance for that specific application.

Product Specifications

• Brand: Sika
• Product name: Sikaflex®-291i
• Product type: Marine adhesive sealant
• Colour: Black
• Pack size: 300 ml cartridge
• Chemical base: One-component polyurethane
• Cure mechanism: Moisture-curing
• Consistency: Non-sag paste
• Finish: Paintable where compatible
• Intended use: Suitable flexible joint sealing in marine construction
• Approval: Wheelmark approved, subject to the applicable documentation

Surface Preparation and Application

For reliable results, follow the current Sika Product Data Sheet and use the product only for applications within its intended scope.

1. Review the documentation: Confirm the product is suitable for the joint, materials and service conditions.
2. Prepare the substrate: Clean and prepare each surface according to Sika’s instructions.
3. Check compatibility: Test adhesion on the actual substrates and verify material compatibility before proceeding.
4. Prepare the cartridge: Use a compatible dispensing gun and follow the manufacturer’s instructions for opening and fitting the nozzle.
5. Apply the sealant: Dispense the material into the prepared joint and finish it according to the recommended procedure.
6. Allow it to cure: Protect the joint as required and allow sufficient time before loading, painting or putting it into service.
7. Follow coating guidance: If painting is required, check the coating system and application timing with Sika.

Do not use the published skin time or open time as a substitute for full curing time. Temperature, humidity and joint dimensions affect curing.

Storage and Handling

• Store the cartridge according to the temperature and shelf-life conditions specified by the manufacturer.
• Keep the product sealed until use and protect it from contamination.
• Follow the current Safety Data Sheet for protective equipment, ventilation and handling.
• Avoid unnecessary contact with skin and eyes.
• Follow the SDS for first aid, spill response and disposal.
• Check the manufacturing date, expiry date and condition of the cartridge before use.

Why Choose Sikaflex®-291i?

For suitable marine sealing tasks, Sikaflex®-291i offers a flexible, moisture-curing polyurethane formulation with good non-sag properties and adhesion to a range of common marine materials. Its paintability, non-corrosive characteristics and marine approval make it a useful option where the product specification matches the application.

Correct substrate preparation, compatibility testing and adherence to the manufacturer’s instructions are essential to achieving the intended result.

Order Sikaflex®-291i Black – 300 ml

Choose Sikaflex®-291i Marine Adhesive Sealant, Black, 300 ml Cartridge for suitable boat and yacht sealing projects.

Before ordering, confirm stock availability, pack size, product authenticity, shelf life and delivery arrangements. Consult the current Sika Product Data Sheet and Safety Data Sheet before application.