Sikasil® WS-302 ME
Sikasil® WS-302 ME is a durable, neutral-curing silicone sealant with good adhesion to a wide range of substrates. It is particularly suited as a sealant for shop fronts, glass partition walls and other applications.
- Very good weathering resistance
- ASTM C 920, class 25
- Very good workability
- Neutral cure
- VOC test report (US EPA 24)
- VOC Emission Test Report (CDPH)
PRODUCT BENEFITS
- Very good weathering resistance
- ASTM C 920, class 25
- Very good workability
- Neutral cure
- VOC test report (US EPA 24)
- VOC Emission Test Report (CDPH)
Usage
Sikasil® WS-302 ME can be used for weatherproofing and sealing applications where durability under severe conditions is required.It is particularly suited as a sealant for shop fronts, glass partition walls and other applications. This product is suitable for experienced professional users only. Tests with actual substrates and conditions have to be performed ensuring adhesion and material compatibility.
Packaging
| Cartridge Unipack Drum | 300 ml 200 l |
Product Details
| Chemical base | 1-component silicone | |
| Color (CQP001-1) | Translucent | |
| Density (uncured) | 0.98 kg/l | |
| Application temperature | +5 °C to +40 °C | |
| Skin time (CQP019-1) | 15 minutes A | |
| Tack free time (CQP019-3) | 70 minutes A | |
| Curing speed (CQP049-1) | (see diagram) | |
| Shore A hardness (CQP023-1 / ISO 48-4) | 25 | |
| Tensile strength (CQP036-1 / ISO 527) | 0.4 Mpa | |
| Elongation at break (CQP036-1 / ISO 527) | 400 % | |
| Service temperature | −40 °C to +150 °C | |
| Shelf life | 12 months B |
| CQP = Corporate Quality Procedure | A) 23 °C / 50 % r. h. | B) storage below 25 °C |
CURE MECHANISM
Sikasil® WS-302 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-302 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-302 ME can be processed with manual, pneumatic or electric driven piston guns as well as pump equipment. For advice on selecting and setting up a suitable pump system, contact the System Engineering Department of Sika Industry.For optimum performance the joint width needs to be designed according to the move-ment 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 ma-terial 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 or adhesive. When tooling freshly applied Sikasil® WS-302 ME press the adhesive to the joint flanks to get a good wetting of the bonding surface. No tooling agents to be used.
Removal
Uncured Sikasil® WS-302 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-302 ME cannot be overpainted.
Application limits
The optimum temperature for substrate and sealant is between 15 °C and 25 °C.
Sikasil® WS-302 ME can be processed with manual, pneumatic or electric driven piston guns.
To exclude materials influencing Sikasil® WS-302 ME, 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 one. Sikasil® WS-302 ME may only be used in combination with structural glazing applications after a detailed examination of the corresponding project details.
Do not use Sikasil® WS-302 ME on PMMA and PC elements as it may cause environmental stress cracking (crazing).