Dow Dowsil 340 Heat Sink Compound

Dow Dowsil 340 Heat Sink Compound Datasheet
  • Description for Dow Dowsil 340 Heat Sink Compound

    One-Part, White, Moderate thermal conductivity compound. Suitable for thermal coupling of electrical devices and PCB assemblies to heat sinks.

    *See Terms of Use Below

    Brand Dowsil
    Application Type Grease
    1 Part or 2 Part 1 Part
    Material Form Grease
    Industry Diodes, Flyback Transformers, Aircraft engines, PCB assemblies, Heat Sink Compound, Aircraft engines, E-Mobility Solutions, Smart Meters, Smart Home Devices, Electrical devices, High-voltage corona, Silicon-controlled rectifiers, Transistors, TV sets
    Manufacturer Dow
    Chemistry Zinc Oxide, Polydimethylsiloxane
    Viscosity (cPs) 542,000, Non-flowing, Low bleed
    Color White
    Arc Resistance (sec) Arc resistance
    Ozone Resistance Ozone resistance
    Chemical Resistance Good
    Relative Solvent Resistance Chemical Resistance: Resistance to minimal or intermittent solvent exposure
    High Temperature Resistance (°C) 177, 200, Thermal Resistance, High-temperature stability, 0.16 (°C*cm2/W)
    Low Temperature Resistance (°C) -45, -55, Low thermal resistance
    Evaporation (%) 0
    Can Be Used In Conjunction With These Materials Silicone materials
  • Technical Data for Dow Dowsil 340 Heat Sink Compound

    Overview
    • Application Type
    • 1 Part or 2 Part
      • 1 Part or 2 Part - 1 Part
    • Material Form
      • Grease
    • Industry
      • E-Mobility Solutions
      • Aircraft - Aircraft engines
      • Electronics - Diodes, Electrical devices, High-voltage corona, Silicon-controlled rectifiers, Transistors, TV sets
      • Transformers - Flyback Transformers
      • Printed Circuit Board (PCB) - PCB assemblies
      • Heat sink - Heat Sink Compound
      • Smart Meters
      • Smart Home Devices
      • Engine - Aircraft engines
    • Chemistry
      • Other - Zinc Oxide
      • Silicone - Polydimethylsiloxane
    • Application Method
      • Dispenser - Automated or manual dispensing
    • Cure Method
      • None - Non-curing
    • Color
      • White
    • Can Be Used In Conjunction With These Materials
      • Other - Silicone materials
    • Brand
      • Dowsil
    Specifications
    Cure Specs
    Viscosity (cPs) 542,000, Non-flowing, Low bleed
    Material Resistance
    Arc Resistance (sec) Arc resistance
    Ozone Resistance Ozone resistance
    Chemical Resistance Good
    Relative Solvent Resistance Chemical Resistance: Resistance to minimal or intermittent solvent exposure
    UV Resistance UV resistance
    High Temperature Resistance (°C) 177, 200, Thermal Resistance, High-temperature stability, 0.16 (°C*cm2/W) Test Method
    Low Temperature Resistance (°C) -45, -55, Low thermal resistance
    Conductivity
    Dissipation Factor 0.00100, 0.02000 Test Method
    Dielectric Strength (V/mil) 210 Test Method
    Dielectric Constant 5.00, 5.00 Test Method
    Thermal Conductivity (W/m°K) High, 0.67, Moderate thermal conductivity
    Volume Resistivity (O) 2.2E+15, 2e15 (ohms/cm) Test Method
    Other Properties
    Specific Gravity 2.100 Test Method
    Evaporation (%) 0
    Flash Point (°F) 213.8
    Business Information
    Shelf Life Details The product should be stored in its original packaging with the cover tightly attached to avoid any contamination. Store in accordance with any special instructions listed on the product label. The product should be used by the indicated Exp. Date found on the label.
    Shelf Life Temperature (°F) 100
    Shelf Life (mon) 60
    Not Good For
    Don't Use With Non-reactive metal substrates, Non-reactive plastic surfaces, Teflon, Polyethylene, Polypropylene
  • Best Practices for Dow Dowsil 340 Heat Sink Compound

    *See Terms of Use Below

    1. Surface Preparation

      All surfaces should be thoroughly cleaned and/or degreased with solvents such as Dow Corning® brand OS Fluids, naphtha, mineral spirits, or methyl ethyl ketone (MEK). 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 to remove residues that may be left behind by other cleaning methods. On some surfaces, different cleaning techniques will give better results than others. Users should determine the best techniques for their applications.

    2. Mixing

      Upon standing, some filler may settle to the bottom of the liquid after several weeks. To ensure a uniform product mix, the material in each container should be thoroughly mixed prior to use.

      Two-part materials should be mixed in the proper ratio either by weight or volume. The presence of light-colored streaks or marbling indicates inadequate mixing.

    3. Deairing/Degassing

      Automated airless dispense equipment can be used to reduce or avoid the need to de-air. If de-airing is required to reduce voids in the cured elastomer, consider a vacuum de-air schedule of >28 inches Hg (or a residual pressure of 10-20 mm of Hg) for 10 minutes or until bubbling subsides.

    4. Curing

      The one-part moisture-cure adhesives are generally cured at room temperature and in a range of 20 to 80 percent relative humidity. Greater than 90 percent of their full physical properties should be attained within 24 to 72 hours depending on the product chosen. These materials are not typically used for highly confined or deep section cures. Materials will generally cure about 0.25 inch (6.35 mm) per 7 days. Addition-cure adhesives should be cured at 100ºC (212ºF) or above. The cure rate is rapidly accelerated with heat (see heat-cure times in Typical Properties table). Thin sections of less than 2 mils may be cured in 15 minutes at 150ºC (302ºF). For thicker sections, a pre-cure at 70ºC (158ºF) may be necessary to reduce voids in the elastomer. Length of pre-cure will depend on section thickness and confinement of adhesive. It is recommended that 30 minutes at 70ºC (158ºF) be used as a starting point for determining necessary pre-cure time. Addition-curing materials contain all the ingredients needed for cure with no by-products from the cure mechanism. Deep-section or confined cures are possible. Cure progresses evenly throughout the material. These adhesives generally have long working times.

    5. 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 for elastomers and adhesives on a particular substrate, 100 percent cohesive failure of the adhesive in a lap shear or similar adhesive strength is needed. This ensures compatibility of the adhesive with the substrate being considered. Also, this test can be used to determine minimum cure time or to detect the presence of surface contaminants such as mold release agents, oils, greases and oxide films.

  • Comparable Materials for Dow Dowsil 340 Heat Sink Compound

    *See Terms of Use Below

    Spec Engine® Results

Questions about this material?

Get personal assistance with your specific application needs.

Your Profile Edit
  1. 92ae2509-e44d-459a-99f0-fb3bc52db6ac
  2. 92ae2509-e44d-459a-99f0-fb3bc52db6ac

Popular Articles

Infographic: ENSURING A STRONG BOND - 6 Basic Methods of Surface Preparation

Read Article

Lubricants 101

Read Article

Testing the effectiveness of surface treatments

Read Article

Lubricants In-Depth: Silicone Compounds

Read Article

Sponsored Articles

Unique Advantages of Contact Adhesives

Read Article

Using LOCTITE® 454™ is a Valid Option for Engineers Working with a Wide Variety of Materials

Read Article

Sylgard 184 by DOW is the Top Choice for a Transparent, Silicone Encapsulant. Read Why:

Read Article

Case Study: Creating reliable, corrosion-free bonds with LORD® 406 acrylic adhesive

Read Article
Information provided by Gluespec

Why Register?

  • View Technical Details
  • View Test Methods
  • View Key Specifications
  • View Similar Materials
  • Save your Project Searches

Already registered? Sign in.

Questions? Learn more about Gluespec

Gluespec Poll

Who do you read or follow for engineering news and entertainment?
High Temperature Resistance Test Methods
High Temperature Resistance Test Method
177°C
200°C
Thermal Resistance
High-temperature stability
0.16 (°C*cm2/W) Thermal Resistance at 40 psi
Dielectric Constant Test Methods
Dielectric Constant Test Method
5.00 100 Hz, ASTM D 150
5.00 100 KHz, ASTM D 150
Dielectric Strength Test Methods
Dielectric Strength Test Method
210 V/mil ASTM D 149, Measured using a sample thickness of 50 mils.
Dissipation Factor Test Methods
Dissipation Factor Test Method
0.00100 100 Hz, ASTM D 150
0.02000 100 KHz, ASTM D 150
Volume Resistivity Test Methods
Volume Resistivity Test Method
2.2E+15
2e15 (ohms/cm) ASTM D 1169
Specific Gravity Test Methods
Specific Gravity Test Method
2.100 Uncured