Sikaflex -298 Slightly Thixotropic 1-Component PU Bedding Compound for Marine Applications
A slightly thixotropic 1-component polyurethane adhesive that cures on exposure to atmospheric humidity. Used for teak deck bedding and meets the regulations set out by the International Maritime Organization (IMO).
Professional Use — Suitable for experienced professional users only. As it is prone to stress cracking, it should be tested with the actual substrates and conditions to confirm adhesion and material compatibility before full application.
P.O Box 2806, Industrial Area 15, Sharjah UAE — expert coordination, authentic supply, site-ready delivery.
What is Sikaflex-298?
Sikaflex-298 is a slightly thixotropic, 1-component polyurethane adhesive that cures on exposure to atmospheric humidity. It is used for bedding-in teak plank decking onto sub-deck surfaces and for bonding synthetic resin deck coverings (excluding polyethylene and polypropylene), and meets the regulations set out by the International Maritime Organization (IMO).
Recommended substrates include GRP, marine plywood, steel, stainless steel, and aluminium treated with an anti-corrosion coating (epoxy or polyurethane-acrylic based). Its longer skinning time makes it well suited to work at elevated temperatures and/or higher humidity. Suitable for experienced professional users only; test with the actual substrates and conditions before use, as it is prone to stress cracking.
Recommended Substrates
Key Benefits
- Long open time — gives enough time to position and adjust coverings smoothly across large surface areas.
- Slightly thixotropic — offers easy handling and good sag control during application.
- Sound-deadening — dampens the deck layer to reduce impact noise and vibrations.
- Elastic behaviour — adapts smoothly to the structural shifting of the boat and absorbs shocks.
- Contains no highly inflammable solvents — safer handling on board.
- IMO compliant — meets International Maritime Organization regulations for marine use.
Cured Mechanical Properties
Chemical & Physical Properties
| Base Chemistry | 1-component polyurethane |
| Colour | Brown |
| Cure Mechanism | Moisture |
| Density (uncured) | 1.2 kg/l (depending on colour) |
| Non-Sag Properties | Slightly thixotropic |
| Application Temperature | 10 – 35 °C (ambient) |
| Skin Time | 100 minutes A |
| Shrinkage | 6% |
| Shore A Hardness | 30 |
| Tear Propagation Resistance | 4 N/mm |
| Shelf Life | 12 months B |
A — 23 °C / 50 % r.h. · B — Storage below 25 °C.
Curing Speed
| 23 °C / 50% r.h. | 4 mm after day 1, up to 10 mm after 4–5 days |
| 10 °C / 50% r.h. | 2–3 mm after day 1, up to 10 mm after 9–10 days |
Pack Sizes & Chemical Resistance
| Pack Sizes | Unipack (600 ml), Pail (10 L) |
| Consumption | Approx. 1.12 l/m² (notched spreader) |
| Shelf Life | Unipack 12 months · Pail 9 months (below 25°C) |
| Good Resistance | Fresh water, seawater, diluted acids & caustic solutions |
| Temporary Resistance | Fuels, mineral oils, vegetable & animal fats/oils |
Application Guide
Follow these steps for reliable teak-deck bedding and covering installation with Sikaflex-298. The optimum temperature for both substrate and product is between 15 °C and 25 °C. Always refer to the current Sika Product Data Sheet.
Surface Preparation
Surfaces must be clean, dry and free from grease, oil and dust, and should be treated according to the specific nature of the substrate — correct preparation is crucial for a long-lasting bond. Use the appropriate Sika primer/activator for the substrate where required.
Optimal Temperature
The product can be processed between 10 °C and 35 °C, with the understanding that reactivity and application properties change with temperature. The optimum is between 15 °C and 25 °C for both the substrate and the product. Its longer skinning time makes it well suited to work at elevated temperatures and/or higher humidity.
Application Process
Apply over large surface areas using a notched spreader at a consumption rate of roughly 1.12 l/m². When bonding moisture-impervious (non-porous) substrates, or where faster curing is required, lightly mist the adhesive with water immediately prior to assembly. Bring components together to prevent air entrapment, and keep the bond clamped under pressure for a minimum of 3 hours until set.
Overpainting
Painting is possible after skin formation. Where the paint requires a baking process, ensure the sealant is fully cured first. Paints such as 1C-PUR and 2C-Acrylic based systems are usually suitable — conduct preliminary trials under the actual manufacturing conditions to confirm.
Removal
Cured product can be removed physically. Uncured product can be removed using Sika Remover-208 or an alternative suitable solvent.
Chemical Resistance
Once cured, Sikaflex-298 offers general resistance to fresh water, seawater, diluted acids and caustic solutions, with temporary resistance to fuels, mineral oils and vegetable or animal fats and oils. See the Cautions below for chemicals it does not resist.
Open Time in Heat
Parts must always be joined within the open time — the UAE's hot, humid climate shortens it. Never bring bonding parts together once the adhesive has formed a skin.
Chemical Limitations
Not resistant to certain chemicals — organic acids, glycolic alcohol, concentrated mineral acids, caustic solutions or solvents. Avoid exposure to these in service.
Skin Contact
If hands or skin are exposed, clean immediately with hand wipes (Sika Cleaner-350H recommended) or a suitable industrial hand cleaner and water. Never use solvents on the skin.
Paint Elasticity
Paints have lower elasticity than the sealant, which could lead to cracking of the paint over the joint area. Select a flexible paint system where movement is expected.
Related Products
Sikaflex-298 sits within Sika's marine teak-deck bedding and caulking system, working with Sika marine primers and activators. Explore the related products below. All stocked by Highway BMT.