Dow Dowsil 838 Silicone Adhesive Sealant

Overview

• Application Type

  • Adhesive - Bond
  • Sealant

• 1 Part or 2 Part

  • 1-Part

• Material Form

  • Elastomer - Post-Cure: Elastomer
  • Paste - Pre-Cure: Paste

• Substrate

  • Ceramic - Ceramics
  • Glass
  • Metal - Many reactive metals
  • Plastic - Plastics, Resins
  • Other - Selected laminates

• Industry

  • LED (Light-Emitting Diodes) - Light Emitting Diodes (LEDs)
  • Smart Meters
  • Smart Home Devices
  • E-Mobility Solutions
  • Electronics - Circuit boards, CRT module, Sealing in and around electrical leads, Electronic equipment, LCD module, Sealing openings in modules, PDP module, Power supplies, PWBs
  • Printed Circuit Board (PCB) - PCB
  • Industrial - Sealing openings in housings, Yoke assembly
  • Power Tools
  • General Purpose
  • Other - Sealing in and around wired

• Chemistry

  • Silicone - Silicone elastomer

• Application Method

  • Dispenser - Automated or manual needle dispensing systems

• Cure Method

  • Room Temperature / Air Dry - Room temperature cure
  • Moisture / Condensation Cure - Moisture cure
  • Heat - Heat Cure
  • RTV (Room Temperature Vulcanization) - RTV

• Color

  • White

• Key Specifications

  • UL (Underwriters Laboratory), ULC (Underwriters Laboratories of Canada), NFPA (National Fire Protection Association) : UL 94 HB - UL 94HB

• Brand

  • Dowsil

Specifications

Cure Specs

Cure Temperature (°C)	20 to 25 Room temperature, 25, <60	Test Method
Cure Time (min)	2,880, 1,440 to 4,320	Test Method
Viscosity (cPs)	Non-flowing
Fixture or Handling Strength Time (min)	10 to 120
Tack Free Time (min)	46	Test Method
Work / Pot Time (min)	60

Bond Strength

Shear Strength (psi)	140	Test Method
Tensile Strength (psi)	270	Test Method

Material Resistance

Flame Resistance	Good
Environmental Resistance	Environmental resistance
High Temperature Resistance (°C)	200
Low Temperature Resistance (°C)	-45, -55
Moisture/Humidity Resistance	Moisture resistance, Humidity resistance

Conductivity

Dissipation Factor	0.00060, <0.00020	Test Method
Dielectric Strength (V/mil)	Good, Durable, 500
Dielectric Constant	2.64, 2.63	Test Method
Volume Resistivity (O)	2.2E+15 (ohms/cm)

Hardness

Shore A Hardness	31	Test Method
Elongation (%)	430, High
Flexibility	Flexible
Modulus (psi)	60	Test Method

Other Properties

Extrusion Rate (g/sec)	11,952
Specific Gravity	1.020	Test Method
Coefficient of Thermal Expansion (CTE)	375 (Linear (micron/m °C or ppm ))

Business Information

Shelf Life Details	Shelf life is indicated by the “Use Before” date found on the product label. For best results, Dow Corning RTV adhesives should be stored at or below 25°C (77°F). Special precautions must be taken to prevent moisture from contacting these materials. Containers should be kept tightly closed with head or air space minimized. Partially filled containers should be purged with dry air or other gases, such as nitrogen., DOWSIL 838 Silicone Adhesive Sealant should be stored at or below at or below room temperature (away from direct sunlight), maximum 25°C (77°F) in original, unopened containers.; Containers should be kept tightly closed with head or air space minimized. Partially filled containers should be purged with dry air or other gases, such as nitrogen.
Shelf Life Temperature (°F)	<90, 77
Shelf Life Type	from date of manufacture
Shelf Life (mon)	24

Not Good For

Don't Use For	Polypropylene, Teflon®, Polyethylene
Don't Use With	Non-reactive plastic, Rubber substrates that are highly plasticized, Non-reactive metal, Plastic substrates that are highly plasticized,