Description
Sikaflex 221 Polyurethane Sealant/Adhesive Aluminum Gray | Boat Supply Store
Addressing the need for a reliable, weather-resistant sealant and adhesive in demanding marine environments, Sikaflex® 221 offers a robust solution for sealing and bonding critical components. This 1-component, non-sag polyurethane formulation cures with atmospheric humidity, providing high elasticity and durability, and meets ASTM C920 Type S, Grade NS, Class 25 standards. It exhibits exceptional adhesion to a wide array of substrates, including metals, ceramics, and plastics, making it indispensable for hull penetrations on offshore sportfishing vessels or deck hardware installations in humid coastal Texas waters.
Key Features
- Superior adhesion to wood, metals, primers, coatings, ceramics, and plastics
- High elasticity for durable, flexible bonds
- Resistant to aging and weathering for long-term performance
- Non-corrosive formulation protects metal components
- Sandable and overpaintable for a finished aesthetic
- NSF registered for potable water applications
- UL listed for potable water contact
- Non-sag consistency for vertical and overhead applications
Specifications
| Product Specifications | |
|---|---|
| Type | 1-component, non-sag polyurethane sealant/adhesive |
| Cure Mechanism | Atmospheric humidity |
| Substrate Compatibility | Wood, metals, metal primers and paint coatings (2-c systems), ceramic materials, plastics |
| Tensile Strength | ASTM C920 Type S, Grade NS, Class 25 |
| Flammability | Tested and classified in accordance with ANSI/UL 723 |
| Potable Water Certification | NSF registered (black, gray, and white); UL listed (black, gray, and white) |
| Cartridge Size | 10.3oz (300ml) |
| Color | Aluminum Gray |
Who This Is For
Marine enthusiasts, DIY boaters, and professional boat builders and repairers seeking a versatile, durable, and weather-resistant sealant and adhesive for a wide range of applications on and off the water. This product is ideal for professionals and DIYers requiring a high-performance material for critical sealing and bonding tasks.
How It Compares
| Feature | Sikaflex 221 Polyurethane Sealant/Adhesive Aluminum Gray | Competitor |
|---|---|---|
| Type | Polyurethane | Polyurethane, Polyurethane |
| Cure Type | Moisture cure | Moisture cure, Moisture cure |
| Marine Use | Yes | Yes, No |
| Potable Water Certification | NSF/UL Listed | No, No |
| Flexibility | High elasticity | Low (permanent bond), Good |
Common Concerns Answered
How do I clean up excess Sikaflex 221?
Excess Sikaflex 221 material is best cleaned up with a solvent (like mineral spirits) while it is still uncured. Once cured, it will require mechanical removal.
Can the cure time be affected by weather?
Yes, the cure time can be longer in humid or cold conditions as it cures by reacting with atmospheric humidity. Ensure adequate ventilation and appropriate temperature for optimal curing.
Is Sikaflex 221 cost-effective for all projects?
While the initial cost may be higher than some general-purpose adhesives, Sikaflex 221's superior durability, adhesion, and specialized marine certifications justify its price for critical applications where failure is not an option.
Frequently Asked Questions
What surfaces can Sikaflex 221 be used on?
Sikaflex 221 bonds effectively to a wide variety of substrates including wood, metals, metal primers and paint coatings (2-c systems), ceramic materials, and plastics.
Is Sikaflex 221 suitable for marine applications?
Yes, Sikaflex 221 is specifically designed for marine applications, offering high elasticity, durability, and resistance to aging and weathering, making it ideal for use on boats and other marine structures.
Can Sikaflex 221 be painted over?
Yes, Sikaflex 221 is overpaintable after it has cured, allowing you to match existing finishes or apply protective coatings.
How long does Sikaflex 221 take to cure?
Sikaflex 221 cures by exposure to atmospheric humidity. The cure time varies depending on humidity and temperature, but it forms a durable elastomer upon curing.
Is Sikaflex 221 waterproof once cured?
Yes, Sikaflex 221 provides a durable, watertight seal once it has fully cured, making it suitable for applications exposed to water.
