Dow Dowsil 738 Electrical Sealant

Dow Dowsil 738 Electrical Sealant Datasheet
  • Description for Dow Dowsil 738 Electrical Sealant

    One-part, RTV silicone sealant, low odor, neutral cure, will not damage corrosion sensitive materials, cures to a tough rubbery solid.

    *See Terms of Use Below

    Brand Dowsil
    Application Type Bond, Sealant
    1 Part or 2 Part 1 Part
    Material Form Nonslumping paste
    Substrate Glass, Many reactive metals, Plastics, Ceramics, Silicone or organic resins
    Industry E-Mobility Solutions, Smart Meters, Power Tools, Smart Home Devices
    Manufacturer Dow
    Chemistry Silicone, Vulcanized silicone rubber, Polydimethylsiloxane
    Application Method Spatula
    Cure Method Moisture
    Cure Temperature (°C) Room temp cure
    Viscosity (cPs) Non-flowing
    Color White
    High Temperature Resistance (°C) 200
    Low Temperature Resistance (°C) -45, -55
    Durability Tough
    Key Specifications UL, Mil-Spec (United States Military Standard): MIL-A-46146
  • Technical Data for Dow Dowsil 738 Electrical Sealant

    Overview
    • Application Type
    • 1 Part or 2 Part
      • 1 Part or 2 Part - 1 Part
    • Material Form
      • Paste - Nonslumping paste
    • Substrate
      • Ceramic - Ceramics
      • Glass
      • Metal - Many reactive metals
      • Plastic - Plastics, Silicone or organic resins
      • Other - Selected laminates
    • Industry
      • E-Mobility Solutions
      • Smart Meters
      • Smart Home Devices
      • Power Tools
    • Chemistry
      • Other - Polydimethylsiloxane
      • Silicone - Vulcanized silicone rubber
    • Application Method
      • Dispenser - Automated or manual needle dispense
      • Spatula/Trowel - Spatula
    • Cure Method
      • Moisture / Condensation Cure - Moisture
    • Color
      • White
    • Key Specifications
      • UL (Underwriters Laboratory), ULC (Underwriters Laboratories of Canada), NFPA (National Fire Protection Association) - UL
      • Mil-Spec (United States Military Standard): A-46146 - MIL-A-46146
    • Brand
      • Dowsil
    Specifications
    Cure Specs
    Cure Temperature (°C) Room temp cure
    Viscosity (cPs) Non-flowing
    Tack Free Time (min) 89 Test Method
    Work / Pot Time (min) 20 Test Method
    Bond Strength
    Peel Strength (piw) 24 (ppi) Test Method
    Tensile Strength (psi) 360
    Material Resistance
    High Temperature Resistance (°C) 200
    Low Temperature Resistance (°C) -45, -55
    Conductivity
    Dielectric Strength (V/mil) 475
    Hardness
    Durability Tough
    Shore A Hardness 35
    Elongation (%) 500, High
    Modulus (psi) 70 Test Method
    Other Properties
    Specific Gravity 1.040 Test Method
    Business Information
    Shelf Life Details When stored at or below 90°F (32°C), Dow Corning 738 Electrical Sealant has a shelf life of 7 months from date of manufacture.;Since this material cures by reaction with moisture in the air, keep the container tightly sealed when not in use. A plug of cured material may form in the tip of the tube during storage, but is easily removed and does not affect the remaining contents.
    Shelf Life Temperature (°F) <90
    Shelf Life Type from the date of manufacture
    Shelf Life (mon) 7
    Not Good For
    Don't Use With surfaces to be painted
  • Best Practices for Dow Dowsil 738 Electrical Sealant

    *See Terms of Use Below

    1. Surface Preparation

      All surfaces should be thoroughly cleaned and/or degreased with Dow Corning® brand OS Fluids, naphtha, mineral spirits, methyl ethyl ketone (MEK) or other suitable solvent. Solvents such as acetone or isopropyl alcohol (IPA) do not tend to remove oils well, and any oils remaining on the surface may interfere with adhesion. Light surface abrasion is recommended whenever possible, because it promotes good cleaning and increases the surface area for bonding. A final surface wipe with acetone or IPA is also useful. Some cleaning techniques may provide better results than others

      users should determine the best techniques for their particular applications.

    2. Application

      Apply Dow Corning 738 Electrical Sealant to the prepared surface in a uniform thickness of 10 to 30 mils. If this adhesive/sealant is to be used between two surfaces, apply to one surface and allow it to establish uniform contact before putting the other surface in place. When placing the second surface, use enough pressure to displace the adhesive/sealant.

    3. Curing

      Let the unit stand undisturbed at room temperature until it cures sufficiently. The odor given off during cure is due to the liberation of an alcohol. The odor will disappear when the cure is complete.

      Curing continues inward from the surface. In 24 hours (at room temperature and about 50 percent relative humidity), Dow Corning 738 Electrical Sealant will cure to a depth of 70 mils. If both bonded members are impermeable to moisture, as in the case of two metal plates, cure time will depend on the thickness of Dow Corning 738 Electrical Sealant and the area under the joint. The larger the unexposed bond area, the longer the cure time required. For shorter cure time and maximum bond strength, keep the area enclosed by a joint to a minimum. For best results, a metal-to-metal bond should not overlap more than one inch.

    4. Testing

      Due to the wide variety of substrate types and differences in substrate surface conditions, general statements on adhesion and bond strength are impossible. To ensure maximum bond strength on a particular substrate, 100 percent cohesive failure of the adhesive in a lap shear or similar adhesive strength test is desired. This ensures compatibility of the adhesive with the substrate being considered. Also, this test can be used to determine minimum cure time or can detect the presence of surface contaminants such as mold release agents, oils, greases and oxide films.

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Tack Free Time Test Methods
Tack Free Time Tack Free Temperature
89 min 25°C
Work / Pot Time Test Methods
Work / Pot Time Test Method Temperature
20 min CTM 0098, At 77°F 25°C and 50% RH. 25°C
Peel Strength Test Methods
Peel Strength Test Method
24 (ppi) Unprimed Adhesion - 180 Degree Peel Strength
Modulus Test Methods
Modulus Test Method
70 psi Tensile Modulus
Specific Gravity Test Methods
Specific Gravity Test Method
1.040 Cured