Sikasil® WS-304 ME
Sikasil® WS-304 ME is a one-component, durable, neutral-curing silicone sealant with a high movement capability and good adhesion to a wide range of substrates. It is particularly suited as a weather seal for structural glazing, curtain walling and windows in hot and tropical climatic conditions.
- Meets requirements of ASTM C920 for Type S, Grade NS, Class 50 (movement capability ± 50 %)
- Low VOC content (< 20 g/L)
- Low emitting material
- Good UV and weathering resistance
- Adheres well to glass, metals, coated/ painted metals and wood
Usage
Sikasil® WS-304 ME can be used for weatherproofing and sealing applications where durability under severe conditions is required.It is particularly suited as a weather seal for structural glazing, curtain walling and windows.
This product is suitable for experienced professional users only. Tests with actual substrates and conditions have to be performed ensuring adhesion and material compatibility.
Advantages
- Meets requirements of ASTM C920 for Type S, Grade NS, Class 50 (movement capability ± 50 %)
- Low VOC content (< 20 g/L)
- Low emitting material
- Good UV and weathering resistance
- Adheres well to glass, metals, coated/ painted metals and wood
Packaging
| Cartridge | 300 mL |
| Unipack | 600 mL |
| Drum | 200 L |
Colour
Black, whiteProduct Details
| Chemical base | 1-component silicone | |
| Colour (CQP001-1) | Black, white | |
| Cure mechanism | Moisture-curing | |
| Density (uncured) | 1.2 kg/L | |
| Non-sag properties (CQP061-4 / ISO 7390) | Good | |
| Application temperature | ambient | 5 ─ 40 °C |
| Skin time (CQP019-1) | 40 minutes A | |
| Tack free time (CQP019-3) | 120 minutes A | |
| Shore A hardness (CQP023-1 / ISO 48-4) | 25 B | |
| Tensile strength (CQP036-1 / ISO 527) | 1.0 MPa | |
| 100 % modulus (CQP036-1 / ISO 527) | 0.3 MPa | |
| Elongation at break (CQP036-1 / ISO 527) | 600 % | |
| Tear propagation resistance (CQP045-1 / ISO 34) | 4 N/mm | |
| Service temperature | -40 ─ 150 °C | |
| Shelf life | 12 months C |
| CQP = Corporate Quality Procedure | A) 23 °C / 50 % r. h. | |
| B) after 28 days | C) storage below 25 °C |
CURE MECHANISM
Sikasil® WS-304 ME cures by reaction with atmospheric moisture. At low temperatures the water content of the air is generally lower and the curing reaction proceeds somewhat slower (see diagram 1).
The curing speed of the reaction depends mainly on the relative humidity and temperature. Material temperature above 50 °C could lead to bubble formation and has to be avoided.
Diagram 1: Curing speed Sikasil® WS-304 ME
Application
Surface Preparation
Surfaces must be clean, dry and free from grease, oil and dust. Surface treatment depends on the specific nature of the substrates and is crucial for a long lasting bond.
Application
Sikasil® WS-304 ME can be processed with manual, pneumatic or electric driven piston guns.
Joint design
Joints must be properly dimensioned. For optimum performance the joint width needs to be designed according to the movement capability of the sealant based on the actual expected movement. The minimum joint depth is 6 mm and a width / depth ratio of minimum 2:1 and maximum 4:1 must be respected.
Note: Joints deeper than 15 mm must be avoided.
For backfilling, it is recommended to use closed cell, sealant compatible foam backer rods, such as high resilience polyethylene foam rod. If joints are too shallow for backing material to be employed, we recommend using a polyethylene tape. This acts as a release film (bond breaker), allowing the joint to move and the silicone to stretch freely.
Tooling and finishing
Tooling and finishing must be carried out within the skin time of the sealant. When tooling freshly applied Sikasil® WS-304 ME press the adhesive to the joint flanks to get a good wetting of the bonding surface. No tooling agents are to be used.
Removal
Uncured Sikasil® WS-304 ME may be removed from tools and equipment with Sika® Remover-208 or another suitable solvent. Once cured, the material can only be removed mechanically.
Hands and exposed skin have to be washed immediately using hand wipes such as Sika® Cleaner-350H or a suitable industrial hand cleaner and water. Do not use solvents on skin.
Overpainting
Sikasil® WS-304 ME cannot be overpainted.