Sikasil® WS-395
Non-staining, neutral-curing silicone weatherproofing sealant
Sikasil® WS-395 is a neutral curing silicone sealant with high movement capability and adhesion to a wide range of substrates. It is particularly suited as a weather seal for sensitive porous stone and metal panel substrates to reduce residue rundown and substrate staining. Sikasil® WS-395 is also typically used for weathersealing curtain walls and glass butt joints or as a perimeter weather seal for windows, doors, and window walls. Further, the product properties of Sikasil® WS-395 are beneficial for field and shop applications related to rainscreen facades, prefabricated exterior wall systems and modular construction.
- Meets the requirements of ASTM C920 Type S, Grade NS, Class 50, Use NT, M, G, A
- Non-staining acc. to ASTM C1248
- Meets the requirements of ASTM C1184, Type S, Use G
- Good UV and weathering resistance
- Adheres well to many substrates including concrete, natural stone, glass, metals, coated and painted metals, vinyl and wood
PRODUCT BENEFITS
- Meets the requirements of ASTM C920 Type S, Grade NS, Class 50, Use NT, M, G, A
- Non-staining acc. to ASTM C1248
- Meets the requirements of ASTM C1184, Type S, Use G
- Good UV and weathering resistance
- Adheres well to many substrates including concrete, natural stone, glass, metals, coated and painted metals, vinyl and wood
Usage
Sikasil® WS-395 can be used for weatherproofing and sealing applications where durability under severe conditions is required. 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 | 295 ml |
| Unipack | 600 ml |
Product Details
| Chemical base | 1-component silicone | |
| Color (CQP001-1) | White, Colonial White, Aluminum, Limestone, Black, Bronze, Medium Bronze, | |
| Cure mechanism | Moisture-curing | |
| Cure type | Neutral | |
| Density | 1.14 kg/l | |
| Non-sag properties (CQP061-4 / ISO 7390) | 0 mm | |
| Application temperature | Ambient | 5 ─ 40 °C (41 ─ 104 °F) |
| Skin time (CQP019-1) | 25 minutes A | |
| Tack free time (CQP019-3) | 50 minutesA | |
| Curing speed (CQP049-1) | See diagram 1 | |
| Shore A hardness (CQP023-1 / ISO 48-4) | 7 days cure at 23 °C (73 °F) / 50 % r.h. | 25 |
| Tensile strength (ASTM D412) | 1.4 MPa (200 psi) | |
| Elongation at break (ASTM D412) | 700 % | |
| Tear propagation resistance (CQP045-1 / ISO 34) | 5 N/mm (30 pli) | |
| Service temperature | -40 ─ 150 °C (-40 ─ 302 °F) | |
| Shelf life | 12 months B |
| CQP = Corporate Quality Procedure | A) 23 °C (73 °F) / 50% r.h. | B) stored below 25 °C (77 °F) |
CURE MECHANISM
Sikasil® WS-395 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 (122 °F) could lead to bubble formation and has to be avoided.
Diagram 1: Curing Speed of Sikasil® WS-395
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. Sikasil® WS-395 is designed to obtain adhesion without the use of a primer however, certain substrates may require a primer. Test by applying the sealant and/or primer sealant combination to confirm results and proposed application methods.
Application
The optimum temperature for substrate and sealant is between 15 °C and 25 °C (59 °F and 77 °F).
Sikasil® WS-395 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.
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 (1/4 in.) and a width / depth ratio of minimum 2 : 1 and maximum 4 : 1 must be respected.
Joints deeper than 15 mm (9/16 in.) 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 or adhesive. When tooling freshly applied Sikasil® WS-395 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-395 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 or a suitable industrial hand cleaner and water.
Do not use solvents on skin.
Overpainting
Sikasil® WS-395 cannot be overpainted.
Application Limits
Most Sikasil® WS, SG, IG and WT, silicones manufactured by Sika are compatible with each other.
For specific information regarding compatibility between various Sikasil® products contact the Technical Department of Sika Industry.
To exclude materials influencing Sikasil® WS-395, 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-395 may only be used in combination with structural glazing applications after a detailed examination of the corresponding project details.
Do not use Sikasil® WS-395 on PMMA and PC elements as it may cause environmental stress cracking (crazing).