Sea-Line MS Polymer Sealant – Elastic Marine Adhesive (White/Black/Clear)

Sea-Line MS Polymer is a modern one-component polymer sealant that combines the functions of a sealant and an adhesive, specifically engineered for the demands of marine environments. This flexible sealant is free of isocyanates and solvents, ensuring it is gentle on substrates and compatible with various materials without causing discoloration. Upon curing, it forms an elastic yet strong bond that accommodates vibration, expansion, and contraction while maintaining a waterproof seal. MS Polymer by Sea-Line comes in three colors – white, black, and clear – to suit different finishing needs on your boat.

• Applications: This all-purpose sealant is ideal for sealing and bonding a wide array of boat components such as deck hardware, hatches and portlights, windows, rails, fittings, as well as deck-to-hull joints and interior trim. It is recommended for joining various materials: fiberglass laminates (polyester or epoxy), gelcoat, metals including aluminum and stainless steel (galvanized or acid-resistant), glass and polycarbonate (plexiglass), wood, painted or primed surfaces, and many types of plastic (except PE, PP, PTFE). MS Polymer provides a watertight, flexible seal which makes it perfect for sealing seams between the deck and superstructure, bedding deck fittings, or even interior repairs where a permanently elastic bond is required.
• Characteristics & Advantages: Once cured, Sea-Line MS Polymer remains permanently elastic (elongation at break up to ~500%), allowing it to absorb movements of the structure without cracking. It offers strong anti-vibration and anti-corrosion benefits – the seal won’t absorb water or fail under shock or structural flexing. The product is UV-resistant and saltwater-proof, meaning it will not yellow or degrade under sunlight and marine exposure, even over long periods. MS Polymer requires no priming of the surface before use – simply clean and degrease the area (using Sea-Line Cleaner) and apply the sealant directly. It is non-reactive with sensitive materials: for instance, when bedding acrylic glass (plexiglass) windows, it won’t cause stress cracks or clouding of the pane. After full cure (typically ~24 hours for a 3 mm bead), the sealant can be painted over with any type of paint (including 2K polyurethane paints) to match your boat’s color scheme.
• Ease of Application: Sea-Line MS Polymer is packaged in an innovative 200 ml cartridge with an integrated dispensing mechanism. This means no standard caulking gun is required – simply unlock the nozzle and the built-in dosing regulator, then press the lever to lay down an even bead of sealant. The system ensures a consistent application force and controlled bead thickness throughout the process, making it easy to achieve a professional result even for DIY users. The sealant’s density is ~1.44 g/cm³ and it cures by absorbing moisture from the air; skin-over time is about 15 minutes at 20°C, giving you enough time to tool or shape the seal before it starts to cure. Apply in conditions above +5°C for best results. Tip: For maximum adhesion, lightly sand the surfaces (e.g., P80-P120 for wood/metal, P200-P400 for plastic/fiberglass) and ensure they are dust-free and degreased before applying the sealant.
• Variants & Tips: Sea-Line MS Polymer is available in White – a universal choice for most jobs (code 300008208), Black – suitable for dark components and deck caulking (code 300008210), and Transparent/Clear – perfect for discreet sealing of glass, lights, and other elements (code 300008211). Choose the color that best matches your application. After opening, store any remaining sealant with the nozzle tightly sealed to prevent premature curing in the cartridge. With proper application and care, MS Polymer will provide a reliable seal for many years, even in extreme marine conditions.