What BOSTIK MSR DECK CAULK ADVANCED is and why to choose it

BOSTIK MSR DECK CAULK ADVANCED is a one-component, permanently elastic sealant based on silyl modified polymer (SMP), specifically developed for watertight caulking of teak decks and other deck materials in yacht and boat building. It cures by humidity, offers excellent resistance to UV and weathering, and can be sanded once fully cured, making it ideal for creating durable, visually clean deck seams that withstand demanding marine environments.

Main features

• Marine-grade teak deck caulk designed for watertight sealing of seams in teak and other deck materials.
• Permanently elastic sealant that accommodates deck movements caused by temperature and humidity changes.
• Can be sanded after curing for perfectly flush, smooth seams and a high-quality finish.
• High temperature resistance from -40 °C to +110 °C (tested in cycles of 7 h at 110 °C and 17 h at 23 °C / 50% RH).
• Excellent UV and weather resistance, with durable resistance to both fresh and salt water.
• Fast skin formation of approximately 25 minutes at 23 °C / 50% RH, allowing efficient working times.
• High chemical resistance, supporting the use of suitable teak cleaners within the recommended pH range.
• Solvent- and isocyanate-free formulation, reducing emissions and handling concerns.
• Neutral and low odour during application.
• MED certified by Bureau Veritas (FTP IMO 2010 code) and elastomeric adhesive certification GL class A and B.
• Colour: black, providing a strong visual contrast with teak seams.
• Multiple packaging formats: 290 ml cartridge, 600 ml sausage and 200 l drum.

Technical specifications

• Chemical base: Silyl Modified Polymer (SMP)
• Consistency: paste
• Specific density: approx. 1.4 g/ml
• Colour: black
• Skin formation time: approx. 25 minutes at 23 °C / 50% RH
• Curing mechanism: moisture-curing
• Cure rate after 24 h: approx. 2.5 mm at 23 °C / 50% RH
• Shore A hardness: approx. 48 (DIN 53505 / ISO 37)
• Volume change: approx. < 3% (DIN 52451)
• Tensile stress at 100% elongation: approx. 1.8 MPa (DIN 53504 / ISO 37)
• Tensile strength at break: approx. 3.0 MPa (DIN 53504 / ISO 37)
• Elongation at break: approx. 200% (DIN 53504 / ISO 37)
• Shear strength: approx. 2.1 MPa (ISO 4587 / DIN 53283 / ASTM D1002)
• Temperature resistance in service: -40 °C to +110 °C
• Application temperature: +5 °C to +40 °C (SDS: recommended storage 10–35 °C; application data sheet: +5 to +35/40 °C)
• UV and weather resistance: excellent
• Solvent content: 0%
• Isocyanate content: 0%
• Physical state: solid, paste-like sealant

Adhesion and substrate preparation

• Teak wood: surfaces must be clean, dry and grease-free. Clean teak with Bostik/Simson Cleaner E and allow to dry for at least 5 minutes.
• Primer on teak seams and bonding areas: pretreat with Bostik/Simson Prep P and allow to dry a minimum of 1 hour (maximum 6 hours for bonding, 24 hours for seam pretreatment as specified in the manuals) before applying MSR Deck Caulk Advanced.
• Deck construction on GRP (new): clean with Simson Cleaner I or Cleaner E, then apply Prep M with a clean, lint-free cloth (drying 5–6 hours max.).
• GRP (old): remove old layers, sand lightly with 80–100 grit paper, vacuum thoroughly, then apply Prep M as above.
• Wooden decks: sand if old, vacuum thoroughly and prime bonding areas with Prep P.
• Steel and aluminium decks: due to the variety of coatings and levelling compounds, adhesion tests or consultation with Bostik are recommended.

Storage stability

• Cartouches: 18 months in original unopened packaging, stored dry between +5 °C and +30 °C.
• Sausages: 12 months in original unopened packaging, stored dry between +5 °C and +30 °C.

Applications and use cases

Primary applications

• Watertight caulking of teak deck seams on yachts, sailing boats and other vessels.
• Sealing of joints in decks made from teak and other compatible deck materials.

Recommended joint geometry for teak planks

To ensure durability and allow the elastic sealant to work correctly, the following minimum joint dimensions are recommended between planks:

• Teak plank width 35 mm: joint width 4 mm, depth 6 mm
• Teak plank width 45 mm: joint width 4 mm, depth 6 mm
• Teak plank width 60 mm: joint width 5 mm, depth 6 mm
• Teak plank width 90 mm: joint width 6 mm, depth 7 mm
• Teak plank width 95 mm: joint width 6 mm, depth 8 mm
• Teak plank width 120 mm: joint width 16 mm, depth 10 mm

Application method

• Extrude MSR Deck Caulk Advanced with a manual or pneumatic gun between +5 °C and +35 °C (or +40 °C depending on local data sheet).
• Fill seams from bottom to top to avoid entrapped air, holding the nozzle at about 60–80° and moving at constant speed with a 10–20% overfill.
• Smooth or level the sealant within approximately 25 minutes (at 23 °C / 50% RH) using a spatula or putty knife, slightly moistened with a soap solution. Avoid letting the soap solution penetrate between joint surfaces and sealant.
• Use bond breaking tape at the bottom of the seam where required to prevent three-side adhesion and allow correct elastic movement.
• Depending on temperature and relative humidity, the cured sealant can typically be sanded after about 3–7 days.

Cleaning and maintenance of teak decks with MSR Deck Caulk Advanced

• For regular cleaning, use clean salt water or fresh water and, if needed, a diluted neutral green soap or a mild liquid dish soap at about 1% concentration.
• Use a soft brush or plastic pot scrubber, working parallel to the teak grain or in gentle circular motion.
• Rinse the deck thoroughly with plenty of fresh or salt water to remove soap residues.
• Thanks to the chemical resistance of MSR Deck Caulk Advanced, teak cleaners with a pH between 6 and 8 can be used, following the manufacturer’s instructions.
• Do not use high-pressure cleaning equipment, strong alkaline or acidic two-component cleaners/brighteners, bleach, ammonia, Tri-Sodium-Phosphate (TSP), vinegar or aggressive household detergents, as they can damage both the teak and the seam compound.
• Do not use stiff bristle brushes that can erode the soft grain of teak and affect seam edges.
• Do not oil the deck; teak contains its own natural oil and additional oils can affect surrounding materials.

FAQ

1. What type of decks is BOSTIK MSR DECK CAULK ADVANCED designed for?

It is specifically formulated for watertight sealing of joints in teak decks and other compatible deck materials used in yacht and boat construction.

2. Can the sealant be sanded, and when?

Yes. Once fully cured, MSR Deck Caulk Advanced can be sanded. Depending on temperature and relative humidity, sanding is typically possible after about 3 to 7 days.

3. What temperatures can the cured sealant withstand?

The product offers temperature resistance from -40 °C to +110 °C, based on cyclic testing (10 cycles of 7 h at 110 °C followed by 17 h at 23 °C / 50% RH).

4. Is it resistant to UV and marine environments?

Yes. It shows excellent UV and weather resistance and durable resistance to both fresh and salt water.

5. Does the product contain solvents or isocyanates?

No. The sealant is solvent-free and isocyanate-free (0% content for both).

6. In what colours and formats is it available?

The standard colour is black. It is supplied in 290 ml cartridges, 600 ml sausages and 200 l drums.

7. How should teak be prepared before applying the sealant?

Teak must be clean, dry and grease-free. Clean with Bostik/Simson Cleaner E, allow to dry at least 5 minutes, then prime seam sides or bonding surfaces with Prep P and respect the specified drying time before caulking.

8. What joint dimensions are recommended?

Minimum joint width and depth depend on plank width. For example, a 60 mm plank requires a 5 mm wide, 6 mm deep seam; a 90 mm plank requires 6 mm width and 7 mm depth. See the joint geometry table in this description for more values.

9. How should tools and uncured material be cleaned?

Residues of uncured sealant can be removed with a clean, colourfast cloth moistened with Bostik Liquid 1 or Bostik/Simson Cleaner E. Cured material must be removed mechanically.

10. How long can the product be stored?

In its original unopened packaging, it can be stored for up to 18 months in cartridges and 12 months in sausages at +5 °C to +30 °C in a dry place.

Section 14 – Transport information

According to the Safety Data Sheet for MSR Deck Caulk Advanced Black, this product is not regulated as a dangerous good for transport.

• ADR/RID (land transport): Not regulated – no UN number, no transport hazard class and no packing group assigned; not classified as environmentally hazardous.
• IMDG (sea transport): Not regulated – no UN number, no transport hazard class and no packing group assigned; not a marine pollutant (NP).
• ICAO-TI / IATA-DGR (air transport): Not regulated – no UN number, no transport hazard class and no packing group assigned.
• Special transport precautions: None specified in the SDS.

Section 8 – Personal protection measures

When handling BOSTIK MSR DECK CAULK ADVANCED, follow the personal protection guidance from the Safety Data Sheet:

• General measures: Ensure adequate ventilation, especially in confined spaces. Do not eat, drink or smoke when using the product. Wash hands before breaks and after work.
• Eye/face protection: Wear safety glasses with side shields or goggles complying with EN 166.
• Hand protection: Wear suitable chemical-resistant gloves such as Neoprene, nitrile rubber or butyl rubber with a thickness greater than 0.7 mm. The typical breakthrough time is greater than 480 minutes; confirm the exact breakthrough time with your glove supplier. Gloves must comply with EN 374.
• Skin and body protection: Normally not required under standard conditions of use.
• Respiratory protection: If ventilation is insufficient, use respiratory protection. A respirator conforming to EN 140 with type A/P2 filter or better is recommended. Filter type: organic gases and vapours filter conforming to EN 14387.
• Environmental protection: Avoid uncontrolled release into the environment and prevent the product from entering drains, soil or subsoil.