Description
Sikaflex 291 Fast Cure Sealant Black 10.3oz | Boat Supply Store
Secure critical hull and deck fittings with a sealant engineered for rapid strength development and tenacious adhesion. This 1-component polyurethane elastomeric adhesive and sealant delivers robust performance for applications both above and below the waterline, resisting saltwater degradation effectively. With excellent bond characteristics to common marine substrates including gelcoat, fiberglass, metal, and wood, it provides a reliable seal for various repair and construction projects, even those involving potable water systems or incidental food contact due to NSF and USDA certifications.
Key Features
- Fast cure time for expedited project completion
- Marine-grade polyurethane elastomeric formulation
- Reliable above and below waterline performance
- Resistant to saltwater environments
- Strong adhesion to gelcoat, fiberglass, metal, and wood
- Paintable and sandable for a finished look
- NSF approved for potable water (black and white only)
- USDA approved for incidental food contact applications
Specifications
| Product Specifications | |
|---|---|
| Product | Sikaflex® 291 Fast Cure Adhesive & Sealant |
| Brand | Sika |
| SKU | CWR67312 |
| MPN | 90923 |
| Cartridge Size | 10.3oz (300ml) |
| Color | Black |
| Material Type | 1-component, marine-grade polyurethane elastomeric adhesive and sealant |
| Cure Type | Moisture cure |
| Application Temperature | 40°F to 95°F (4°C to 35°C) |
| Service Temperature | -40°F to 194°F (-40°C to 90°C) |
| Adhesion | Excellent to gelcoat, fiberglass, metal, and wood |
| Paintable | Yes |
| Sandable | Yes |
| Saltwater Resistance | Yes |
| Below Waterline Use | Yes |
| NSF Approval | Yes (potable water, black and white only) |
| USDA Approval | Yes (incidental food contact) |
Who This Is For
Marine professionals and DIY boat owners requiring a rapid-setting, versatile adhesive and sealant for a broad spectrum of marine applications. This product is engineered for both above and below waterline tasks, offering a dependable solution for bonding, sealing, and light-duty assembly on various substrates.
How It Compares
| Feature | Sikaflex 291 Fast Cure Sealant Black 10.3oz | Competitor |
|---|---|---|
| Cure Type | Polyurethane | Moisture-cure polyurethane, Silicone-based |
| Below Waterline Use | Yes | Yes, No |
| Paintable/Sandable | Yes | No, Yes |
| NSF Approved for Potable Water | Yes (black and white only) | No, No |
| USDA Approved for Incidental Food Contact | Yes | No, No |
Common Concerns Answered
How can I mitigate the strong odor during application?
Ensure adequate ventilation in the application area. While the odor is characteristic of polyurethane sealants, it dissipates as the product cures. Consider wearing a respirator if working in confined spaces.
What is the best method for removing Sikaflex 291 once it's fully cured?
Once fully cured, removal typically requires mechanical means such as scraping, cutting with a sharp blade, or sanding. It is advisable to mask surrounding areas and remove any excess material before it begins to cure to simplify cleanup.
Will the cure time be consistent regardless of environmental conditions?
Cure time is temperature and humidity dependent. Cooler temperatures and lower humidity will extend the cure time, while warmer temperatures and higher humidity will accelerate it. Refer to the technical data sheet for specific cure progression rates.
Frequently Asked Questions
Is Sikaflex 291 suitable for use below the waterline?
Yes, Sikaflex 291 is specifically formulated for use both above and below the waterline, offering excellent resistance to saltwater.
Can Sikaflex 291 be painted or sanded?
Yes, Sikaflex 291 is paintable and sandable after it has fully cured, allowing for a custom finish.
What surfaces does Sikaflex 291 adhere to?
Sikaflex 291 demonstrates excellent adhesion to a wide range of common marine substrates, including gelcoat, fiberglass, metal, and wood.
What is the typical cure time for Sikaflex 291?
The skin-over time is approximately 10-60 minutes, and tack-free time is approximately 1-3 hours at 73°F (23°C) and 50% relative humidity. Full cure depends on temperature, humidity, and bead size, typically ranging from 24 hours to several days.
Is Sikaflex 291 NSF approved?
Yes, Sikaflex 291 is NSF approved for potable water applications, specifically for black and white water tanks and systems. Always confirm the exact approval details for your specific application.
