Sikasil® WS-305 S

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

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.

Tooling and finishing

Tooling and finishing must be carried out within the skin time of the sealant.

When tooling freshly applied Sikasil® WS-305 S press the sealant to the joint flanks to get a good wetting of the bonding surface. No tooling agents to be used.

Removal

Uncured Sikasil® WS-305 S can be removed from tools and equipment with Sika® Remover-208 or other suitable solvents. 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-305 S cannot be overpainted.

Application limits

For specific information regarding compatibility between various Sikasil® products contact the Technical Department of Sika Industry.
To exclude materials influencing Sikasil® WS-305 S, all materials such as gaskets, tapes, setting blocks, sealants, etc., in direct and indirect contact have to be approved by Sika in advance.
Where two or more different reactive sealants are used, allow the first to cure completely before applying the next. Sikasil® WS-305 S may only be used in combination with structural glazing applications after a detailed examination of the corresponding project details.

Do not use Sikasil® WS-305 S on PMMA and PC elements as it may cause environmental stress cracking (crazing).