Sikasil® WS-305 S is a durable and high performance neutral-curing silicone sealant with a high movement capability and good adhesion to a wide range of substrates. It can be used for weatherproofing sealing applications where durability under severe conditions is required. It is particularly suited as a weather seal for structural glazing, curtain walling and windows.
Features:
- Meets requirements of GB/T 14683 and ASTM C 920 for Type S, Grade NS, Class 50 (movement capability ± 50 %)
- Very good UV and weathering resistance
- Adheres well to many substrates including glass, metals, coated and painted metals, plastics and wood
- Conformity with LEED v4 EQc 2: Low-Emitting Materials
Preparations:
- 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.
Applications:
- The optimum temperature for substrate and sealant is between 15 °C and 25 °C.
- Sikasil® WS-305 S can be processed with manual, pneumatic or electric driven piston guns. 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. Joints deeper than 15 mm must be avoided.
- For backfilling, it is recommended to use closed cell, sealant compatible foam backer rods e.g. 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.
