DOWSIL 838
Harmonization Code : 3919.10.80 | Other self-adhesive plastic rolls not exceeding 20 cm wide.
Main features
- One-Part Moisture-Cure Application
- Non-Sag Placement Control
- Flexible Cured Material
Product Description
DOWSIL™ 838 Silicone Adhesive Sealant is a one-part, white, non-flowing silicone adhesive for general-purpose bonding, sealing, and component stabilization in electronic assemblies. The moisture-cure material requires no mixing and cures at room temperature, with mild heat below 60°C (140°F) available to accelerate cure. Its non-flowing consistency supports automated or manual needle dispensing, while the cured elastomer combines a Shore A hardness of 31 with a tensile modulus of 0.4 MPa for flexible attachment and sealing. Applications include sealing openings in modules and housings, stabilizing individual components, assembling components on printed wiring boards, sealing around wired and electrical leads, and yoke assembly.
Key features
- One-part room-temperature cure: Requires no mixing or curing oven under standard moisture-cure conditions.
- Non-flowing dispense behavior: Supports controlled application through automated or manual needle dispensing systems.
- Flexible cured silicone: Provides a typical Shore A hardness of 31 and tensile modulus of 0.4 MPa, with a UL 94 HB flammability classification.
Applications / Suitable for
- Sealing openings in electronic modules and housings
- Adding mechanical stability to individual components
- Assembly of components on printed wiring boards
- Sealing around wired and electrical leads
- Yoke assembly
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Physical Properties
Thermal Properties
Additional Information
As-supplied / before-processing properties
Typical values are not intended for use in preparing specifications.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Product form | One-part, non-flowing adhesive | — | As supplied |
| Color | White | — | As supplied |
| Extrusion rate | 199.2 | g/min | Typical value |
| Flow rate – slump | 0 in / 0.1 cm | — | Typical value |
After-processing / final-state properties
Typical cured-material values are not intended for use in preparing specifications.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Specific gravity | 1.02 | — | Cured material; typical value |
| Tensile strength | 270 / 1.9 / 19 | psi / MPa / kg/cm² | Cured material; typical value |
| Tensile modulus | 60 / 0.4 / 4 | psi / MPa / kg/cm² | Cured material; typical value |
| Durometer hardness | 31 | Shore A | Cured material; typical value |
| UL flammability classification | 94 HB | — | UL flammability classification |
| Useful temperature range | -45 to 200 | °C | For most long-term uses; application performance should be verified at temperature extremes |
