Sikasil WS-305 CN Weatherproofing Sealant
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Sikasil WS-305 CN Weatherproofing Sealant

Neutral Curing Silicone Sealant • High Movement Capability • Excellent Adhesion
By: Sika

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Sikasil®WS-305 CN is a neutral curing silicone sealant with a high movement capability and excellent adhesion to a wide range of substrates.

Sikasil® WS-305 CN can be used for weatherproofing and sealing applications where durability under severe conditions is required. Sikasil® WS-305 CN is particularly suited as a weather seal for curtain walls and windows.
This product is suitable for experienced professional users only.
Testing with actual substrates and conditions should be performed to ensure adhesion and material compatibility.

Sikasil WS-305 CN cures by reaction with atmospheric moisture. The reaction starts at the surface and proceeds to the core of the joint. The curing speed depends on the relative humidity and the temperature.
Heating above 122°F to speed up the vulcanization is not advisable as it may lead to bubble formation. At low temperatures the water content of the air is lower and the curing reaction proceeds more slowly.

• Skin time: approx. 50 min
• Tack-free time: approx. 130 min
• Tensile strength (ASTM D 412) 145 psi
• Meets requirements of ASTM C920 (class 50), TT-S00230C, TTS001543A
• Outstanding UV and weathering resistance
• Adheres well to many substrates including glass, metals, coated and painted metals, plastics and wood
• Cannot be over-coated (contains silicone)
• Application temperature: 40°F to 105°F
• Service temperature: -40°F to 302°F
• Shelf life: 12 months (store below 77°F)

Uncured Sikasil WS-305 CN 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 should be washed immediately using a suitable industrial hand cleaner and water. Do not use solvents! Some users may have skin sensitivity to some of the components.

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