3M Marine Adhesive Sealant 5200 Fast Cure 05220 – Permanent Bonding & Waterproof Seals for Boats & RVs (White, 3 fl oz)

Permanent bonding and watertight sealing for boats and RVs

3M Marine Adhesive Sealant 5200 Fast Cure is a one-part polyurethane sealant designed for reliable, long-lasting bonds and seals. It adheres to wood, gelcoat, and fiberglass, while remaining flexible enough to accommodate movement from vibration, swelling, shrinking, or minor shocks. Built to withstand marine exposure and splash, this sealant helps you maintain secure connections across critical joints and fittings.

Key benefits and what to expect

• CURES FAST — No mixing required; typically cures within 48 hours, helping you get back to work or leisure sooner.
• PROFESSIONAL-LEVEL STRENGTH — Extremely strong bonding above or below the waterline for durable performance.
• PERMANENT BONDS — Designed for sealing, bonding, and attaching interior and exterior components on boats and RVs.
• WEATHER AND SALT RESISTANT — Tough polyurethane formulation resists marine weather and salt spray over time.
• FLEXIBLE UNDER MOTION — Stays flexible to absorb vibration and structural movement without cracking or peeling.
• INDUSTRIAL USE ONLY — Suitable for professional, industrial applications; not intended for consumer sale or use.

Ideal applications on watercraft and beyond

• Fiberglass deck to hull connections
• Through-hull fittings and deck hardware
• Wood to fiberglass joints
• Portholes, deck fittings, and deck housings
• Fiberglass transoms and engine mounts
• Under moldings and hull seams above or below the waterline

The 3M Fast Cure sealant is available in cartridge and sausage packs to match your dispensing method, and it pairs with manual or pneumatic applicators for precise, controlled application. While it is a robust marine-grade solution, the product is designed for industrial/occupational use and emphasizes strong, flexible performance in challenging environments.

How it works

As a one-part polyurethane compound, it requires no mixing and adheres to a range of substrates common in boats and RVs. It remains flexible after curing, helping joints endure vibration and movement without compromising the seal. Expect a durable, water-resistant bond that stands up to the elements when properly applied to prepared surfaces.