DOWSIL 983
Harmonization Code : 3919.10.80 | Other self-adhesive plastic rolls not exceeding 20 cm wide.
Main features
- Two-Part Structural Glazing Silicone
- +/-25% ASTM C719 Movement
- 10 to 25-Minute Working Window
Product Description
DOWSIL™ 983 Structural Glazing Sealant is a two-part, neutral-cure RTV silicone sealant for factory-applied structural glazing and weathersealing in curtainwall production. The base and curing agent form a non-sag material that cures at room temperature into a high-modulus, flexible silicone rubber. The product provides unprimed adhesion to most common construction materials and is compatible with reflective glass, laminated glass, and most insulating glass configurations. It meets ASTM C1184 for structural silicone sealants and ASTM C719 Class 25 for movement capability. Structural applications require project-specific review by Dow technical staff.
Key features
- Dual structural and weatherseal capability: Supports factory glazing applications requiring structural attachment and ±25% weatherseal movement performance.
- Structural glazing compliance: Passes ASTM C1184 Structural Silicone Sealant Specification and meets ASTM C719 Class 25.
- Controlled two-part processing: Provides a 10–25 minute working time and less than 5 mm flow or sag when mixed at the documented ratio.
Applications / Suitable for
- Factory structural glazing
- Curtainwall production
- Unitized glazing systems
- Combined structural and weatherseal joints
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Mechanical Properties
Additional Information
As-supplied / before-processing properties
Typical properties for the separately supplied base and curing agent and for the catalyzed material. Values are not intended for specification preparation.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Color and physical form | White paste | — | Base, as supplied |
| Specific gravity | 1.36 | — | ASTM D1475; base, as supplied |
| Color and physical form | Black or gray paste | — | Curing agent, as supplied |
| Specific gravity | 1.055 black; 1.00 gray | — | ASTM D1475; curing agent, as supplied |
| Mix ratio | 9:1 | by volume | Base to curing agent; standard pump ratio. Adjustable from 8:1 to 10:1 by volume |
| Working time | 10–25 | minutes | Catalyzed at 9:1 base-to-curing-agent ratio by volume |
| VOC content | <18 | g/L | Mixed black or gray; value may depend on mixing ratio |
| Flow / sag | <0.2 (<5) | in (mm) | ASTM D2202; catalyzed material |
After-processing / final-state properties
Typical cured properties and specification test results. Mechanical values were measured after seven days at 77°F and 50% relative humidity unless otherwise noted.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Durometer hardness | 30–40 | Shore A points | ASTM C661; after 1 day at 77°F and 50% RH |
| Durometer hardness | 35–45 | Shore A points | ASTM C661; after 7 days at 77°F and 50% RH |
| Ultimate tensile strength | 300 (2.0) | psi (MPa) | ASTM D412; after 7 days at 77°F and 50% RH |
| Tensile strength at 25% strain | 50 (0.35) | psi (MPa) | ASTM C1135; after 7 days at 77°F and 50% RH |
| Ultimate tensile strength | 160 (1.1) | psi (MPa) | ASTM C1135; after 7 days at 77°F and 50% RH |
| Ultimate elongation | 120 | % | ASTM C1135; after 7 days at 77°F and 50% RH |
| Movement capability | ±25 | % | ASTM C719 Class 25 |
| Structural silicone sealant specification | Passes | — | ASTM C1184 |
