Key points of the article
- Marine sealant is an essential element for ensuring protection, durability, and safety in vessels, in an environment characterized by intense UV rays, salt spray, humidity, and continuous mechanical stress.
- H.B. Fuller solutions cover all major marine applications, from decks to inflatable boats, from structural bonding to sandwich panels, ensuring multi-layer adhesion, weather resistance and high long-term elasticity.
- Products such as Körapur® 928 Marine, Körapur™ 666 and Körapur™ 672 meet the technical requirements of the sector thanks to their stability on metal, fiberglass, wood, and composites, as well as resistance to UV rays, humidity, and thermal shock.
- The evolution of marine adhesive and sealant systems now allows for the creation of lighter, more reliable, and more durable vessels, supporting designers and manufacturers in the construction of advanced, high-performance structures.
In the complex marine sector, marine adhesives and sealants must guarantee reliable performance in extreme conditions. The combination of intense UV radiation, constant humidity, fresh water and salt water requires materials capable of maintaining elasticity, adhesion and stability over time.
Similarly, correctly sealing components installed on the deck, hull, and interior environments is essential to avoid corrosion, leaks and damage to the laminate, which can compromise the safety and durability of the vessel.
For these needs, H.B. Fuller, a Mascherpa partner, develops specific solutions for the marine sector. The range includes marine sealants, marine adhesives, structural adhesives and bonded fastening systems, designed to ensure long-term stability in a wide variety of applications, including:
- deck systems;
- interior bonding and sealing;
- cabin construction;
- boat construction;
- exterior sealing;
- below-the-waterline sealing;
- glass bonding;
- inflatable boats;
- acoustic damping;
- marine electronics and speakers;
- Weld Mount (bonded fastening systems).
Key features of marine adhesives and sealants
To ensure reliable performance in marine applications, a marine sealant must provide:
- UV resistance;
- resistance to salt and fresh water;
- adhesion to fiberglass, metal, wood and composites;
- permanent elasticity to absorb movement and vibration;
- sag resistance and stability against atmospheric agents;
- compatibility with vertical and horizontal surfaces.
These requirements are fundamental in all nautical and marine industry applications.
Deck bonding
Decks in teak, PVC or polyurethane are increasingly common on private vessels and cruise ships. In addition to their aesthetic appearance, they contribute to non-slip safety and thermal insulation. Bonding must be performed over the entire surface to avoid cavities that could encourage water accumulation.
In this context, Körapur® 928 Marine is particularly valued for teak bedding, thanks to:
- high elasticity;
- stable adhesion;
- resistance to humidity and UV rays;
- weather stability;
- paintability.
| Product | Technology | Key properties | Skin formation time | Curing after 24 h | Shore A | Elongation at break | Tensile strength |
| Köraflex VP 990 Marine | 1-k synthetic polymer | Good adhesion to wood materials, good resistance to humidity and atmospheric agents, resistance to water and salt water, high UV resistance. | 30 min | 2 mm | 42 | 410 % | 2.0 MPa |
| Körapur 928 Marine | 1-k PUR | Bedding compound for teak decks with long open time, high flexibility. | 75 min | 3 mm | 45 | 800 % | 3.0 MPa |
Deck caulking
Marine decks can be made of natural wood, PVC or polyurethane. For natural wood decks, it is particularly important to provide long-lasting protection for joints against water infiltration.
Our H.B. Fuller products for caulking meet the highest requirements in terms of:
- salt resistance;
- fresh water resistance;
- UV resistance.
Furthermore, the joints allow for permanent absorption of movements while being easy to apply.
In addition, the deck bedding is subject to volume changes and thermal expansion due to temperature differences. I marine sealants meet these needs thanks to high flexibility and the great resistance of the material, which keeps the flooring in place.
I am text block. Click edit button to change this text. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.
Inflatable boats
Inflatable boats are used in very different contexts: from recreational activities such as rafting, diving, and fishing, to more demanding services such as rescue operations, firefighting, or military use. These applications require materials that are highly resistant to impacts, abrasion, climatic variations and variable operating conditions.
Depending on the type of vessel and the environment of use, tube coatings can be made of PVC, TPU, CSPE, synthetic rubber or neoprene.
The adhesive must therefore guarantee secure adhesion even on very different substrates, maintaining the functionality of the vessel over time. For this reason, marine adhesives dedicated to inflatable boats are designed to offer high resistance to UV rays, stability against temperature variations, hydrolysis resistance and durability in harsh conditions.
Correctly performed bonding prevents pressure loss and ensures consistent performance for many years of use.
| Product | Technology | Key properties | Viscosity | Open time | Evaporation time | Pressing time |
| Köraplast 81 Marine | 1- or 2-k solvent-based PUR | Good resistance to humidity, long open time, free of toluene and NEP. | 2,900 mPas | 40 min | 10 min | 8-15 sec |
| Köraplast 82 Marine | 1- or 2-k solvent-based PUR | High initial tack, toluene-free. | 2,700 mPas | 5-20 min | 10 min | 8-15 sec |
| Körapren 88 Marine | 1- or 2-k polychloroprene | High initial tack, toluene-free. | 1,900 mPas | 10-60 min | 10 min | 8-15 sec |
Structural adhesives for marine applications
In modern yachts and vessels, made predominantly of fiberglass (GRP) or aluminum, numerous components must withstand high stresses during navigation.
The connection between deck and hull, the fastening of ribs and stringers, as well as the assembly of flying bridge structures, require adhesive systems capable of guaranteeing structural stability and vibration absorption.
Structural marine adhesives offer significant advantages over traditional mechanical fastenings, as they reduce weight, noise and vibration, avoiding deformation or corrosive phenomena that could compromise the integrity of the surfaces.
The use of screws, rivets or welds can also create potential infiltration points or damage thermal insulation, whereas structural bonding allows for uniform load distribution.
In these applications, solutions such as Körapur™ 666, characterized by high adhesion to metal, fiberglass e plastic, good elasticity, no shrinkage e thermal resistance between -40 °C and +90/+120 °C. Formulations like this are suitable for both structural bonding and sandwich panels, where lightness and rigidity are required.
| Product | Technology | Key properties | Skin formation time | Curing after 24 h | Shore A | Elongation at break | Tensile strength |
| Körapop 954 Marine | 1-k STP | Fast curing, high UV stability. | 10 min | 3 mm | 58 | 380 % | 3.2 MPa |
| Körapur 940 Marine | 1-k PUR | High strength. | 70-90 min | 3 mm | 55 | 400 % | 4.0 MPa |
| Product | Technology | Key properties | Viscosity | Mixed viscosity | Pot life at 20 °C | Mixing ratio by weight |
| Körapur 666 | 2-k PUR | Thixotropic, easy to spread with a spatula, high resistance to humidity, mixing cartridge available. | Paste | 55,000 mPas | Variable between 3 and 90 min | 6:1 |
| Körapur 672 | 2-k PUR | High resistance to humidity. | 35,000 mPas | 10,000 mPas | Variable between 10 and 80 min | 5:1 |
| Körapur 840 | 2-k PUR | High impact resistance, no significant shrinkage, wide range of pot life profiles available. | 420,000 mPas | 45,000 mPas | Variable between 2 and 45 min | 5:1 |
Exterior bonding and sealing
Exterior components must withstand:
- atmospheric agents;
- UV radiation;
- salt spray;
- vibrations.
The different types of elastic marine sealant maintain stability and protection over time.
Below-the-waterline sealing
Maximum reliability is required in this area. A marine sealant must ensure:
- total waterproofing;
- high mechanical strength;
- elasticity to absorb torsion;
- stability during prolonged immersion.
Sandwich panels and decorative panels
In boat and ship construction, sandwich panels are used to create light but strong structures, often used for interior linings, decorative elements, and components requiring a combination of rigidity and weight reduction. Panels can consist of heterogeneous materials such as wood, metal, plastics, or composites with a foam core or honeycomb, configurations that require adhesives capable of adhering to different substrates and maintaining stability over time.
Adhesives dedicated to these applications guarantee uniform load distribution and good resistance to vibration and movement, contributing to the durability of the component.
Among the most used systems for the production of sandwich panels is Körapur™ 672, valued for its ability to adhere to multiple materials and for the stability provided in structural contexts.
| Product | Technology | Key properties | Viscosity | Mixed viscosity | Pot life at 20 °C | Mixing ratio by weight |
| Körapur 666 | 2-k PUR | Thixotropic, easy to spread with a spatula, high resistance to humidity, mixing cartridge available. | Paste | 55,000 mPas | Variable between 3 and 90 min | 6:1 |
| Körapur 672 | 2-k PUR | High resistance to humidity. | 35,000 mPas | 10,000 mPas | Variable between 10 and 80 min | 5:1 |
| Product | Technology | Key properties | Skin formation time | Curing after 24 h | Shore A | Elongation at break | Tensile strength |
| Körapur 928 Marine | 1-k PUR | Bonding of decorative panels, long open time, high flexibility. | 75 min | 3 mm | 45 | 800 % | 3.0 MPa |
| Product | Technology | Key properties | Viscosity | Open time at 20 °C | Pressing time at 40 °C |
| Swift®bond 9060 | 1-k liquid PUR | Designed for the adhesion of various plastic substrates and for the assembly of large panels. | 5,500 mPas | 30 min | 45 min |
| Icema™ R 145/31S | 1-k liquid PUR | Medium open time, high bonding strength | 7,400 mPas | 15 min | 30 min |
| Icema™ R 145/75 | 1-k liquid PUR | Fast product, short open time and short pressing time. | 5,100 mPas | 3 min | 4 min |
| Icema™ R 145/12 | 1-k liquid PUR | Medium open time, good degree of adhesion on most materials, including pre-treated metals. | 3,500 mPas | 7 min | 10 min |
| Product | Technology | Key properties | Viscosity | Open time at 20 °C |
| Rapidex® NP 2075 LT | Reactive Hot Melt | Very high initial strength, excellent bonding on substrates under tension. | 45,000 mPas | 3 min |
| Product | Technology | Key properties | Open time at 20 °C | Viscosity | pH value |
| Rakoll® GXL 3 | 1-k water-based | Easy to apply, very strong bond, meets requirements for D3. | 8-12 min | 13,000 mPas | 3,0 |
Glass bonding
Bonded glass offers modern design and visual continuity.
Adhesives allow for the bonding of:
- mineral glass;
- polycarbonate.
| Product | Technology | Key properties | Skin formation time | Curing after 24 h | Shore A | Elongation at break | Tensile strength |
| Körapur 178 | 1-k PUR | High viscosity, high initial tack and non-sag properties, high UV resistance and color stability. | 35 min | 3 mm | 60 | ≥ 600 % | ≥ 10 MPa |
| Körapop 250 | 1-k STP | High resistance to cold and heat, excellent resistance to humidity and atmospheric agents. | 10 min | 3 mm | 56 | 350 % | 4.7 MPa |
| Körapop 954 Marine | 1-k STP | Fast curing, high UV stability. | 10 min | 3 mm | 58 | 380 % | 3.2 MPa |
| GD 826 N | 1-k silicone | Weather-resistant silicone with very high UV stability. | > 15 min | 2 mm | 23 | 550 % | 0.7 MPa |
| Product | Technology | Key properties | Pot life | Dust-free after | Shore A | Elongation at break | Tensile strength |
| Ködiglaze SDG 30 | 2-k silicone | Fast-curing structural glazing silicone, high UV stability. | 30 min | 90 min | 46 | 230 % | 2.1 MPa |
Window sealing
Windows must withstand:
- structural torsion;
- movements;
- UV radiation;
- extreme marine environment conditions.
Marine sealants and casting resins ensure long-term stability.
The Körapur™ range in the marine sector
The Körapur™ range includes polyurethane adhesive sealants in one-component and two-component versions designed for structural applications, sealing and bonding multi-material typical of the marine industry. Versions dedicated to the marine sector, such as Körapur 925, 928 e 940, use silane-modified formulations that combine high elasticity, resistance extreme conditions humidity e UV rays, thermal stability and applicability even on vertical surfaces thanks to low sag.
These adhesive sealants are suitable for a wide range of activities, including teak lining installation, multi-substrate sealing, sandwich panel assembly, and elastic bonding of metal, wood, or composite components.
Their resistance to typical marine environment conditions and the ability to maintain consistent performance over time make them suitable for numerous stages of boat production and maintenance.
| Product | Technology | Key properties | Skin formation time | Curing after 24 h | Shore A | Elongation at break | Tensile strength |
| Körapop 954 Marine | 1-k STP | Fast curing, high UV stability. | 10 min | 3 mm | 58 | 380 % | 3.2 MPa |
| Körapur 925 Marine | 1-k PUR | Multipurpose | 45 min | 3-4 mm | 45 | 650 % | 3.0 MPa |
| Körapur 940 Marine | 1-k PUR | High strength. | 70-90 min | 3 mm | 55 | 400 % | 4.0 MPa |
Find out more about the different types of marine sealant
A marine sealant must guarantee consistent performance in a complex environment, characterized by atmospheric agents, salt spray, mechanical stress, and thermal variations.
H.B. Fuller solutions, integrated with the Körapur™ range and systems such as Weld Mount, offer advanced technical answers for decks, hulls, fiberglass, structural panels, windows, and inflatable boats, maintaining high standards of safety and reliability over time.
For more information regarding the Körapur™ marine range, contact our Mascherpa experts.
