Dow Dowsil 748 Non-Corrosive Sealant

Dow Dowsil 748 Non-Corrosive Sealant Datasheet
  • Description for Dow Dowsil 748 Non-Corrosive Sealant

    • One-component • Non-Corrosive Sealant • General-purpose • Bonding and sealing applications • Low odor • Easy handling.

    *See Terms of Use Below

    Brand Dowsil
    Application Type Bonding, Sealant
    1 Part or 2 Part 1 Part
    Material Form Paste
    Substrate Acrylic, Glass, Metals, Plastic, Vulcanized silicone rubber, Copper, Other sensitive metals, Silicone
    Industry E-Mobility Solutions, Smart Meters, Power Tools, Smart Home Devices, Corrosion-sensitive PCB system assemblies, Corrosion-sensitive electrical assemblies, General-purpose
    Manufacturer Dow
    Chemistry Silicone
    Application Method Spatula
    Cure Method Moisture cure
    Cure Temperature (°C) 25, 25, 20 to 25 Room temperature
    Odor Details Low
    Cure Time (min) 2,160, 10,080, <1,440, <4,320
    Viscosity (cPs) NonFlow, Non-slump
    Color Off-white (cured)
    Ozone Resistance Resistance to ozone
    High Temperature Resistance (°C) 177, 204
    Low Temperature Resistance (°C) -55
    Other Resistance Resistance to corona
    Durability Tough, Durable
    Extrusion Rate 150 (g/min)
    Key Specifications FDA (U.S. Food & Drug Administration) and/or CFIA (Canadian Food Inspection Agency): Complies with FDA regulation CFR 177.2600 covering indirect food contact, UL (Underwriters Laboratory), ULC (Underwriters Laboratories of Canada), NFPA (National Fire Protection Association): Meets UL 94 Flame class, 94 HB. UL File No. E 40195 (N)., Mil-Spec (United States Military Standard): MIL-A-46146
  • Technical Data for Dow Dowsil 748 Non-Corrosive Sealant

    Overview
    • Application Type
    • 1 Part or 2 Part
      • 1 Part or 2 Part - 1 Part
    • Material Form
      • Paste
    • Substrate
      • Glass
      • Metal - Metals, Other sensitive metals
      • Copper
      • Plastic - Silicone
      • Acrylic (PMMA) - Acrylic
      • Silicone Rubber - Vulcanized silicone rubber
      • Other - Organic resins
    • Industry
      • E-Mobility Solutions
      • Electronics - Corrosion-sensitive electrical assemblies
      • Smart Meters
      • Smart Home Devices
      • Printed Circuit Board (PCB) - Corrosion-sensitive PCB system assemblies
      • Power Tools
      • General Purpose - General-purpose
      • Other - A wide range of sealing applications, A wide range of bonding applications
    • Chemistry
    • Application Method
      • Spatula/Trowel - Spatula
    • Cure Method
      • Moisture / Condensation Cure - Moisture cure
    • Color
      • Off-White - Off-white (cured)
    • Key Specifications
      • FDA (U.S. Food & Drug Administration) and/or CFIA (Canadian Food Inspection Agency): 177.2600 - Complies with FDA regulation CFR 177.2600 covering indirect food contact
      • UL (Underwriters Laboratory), ULC (Underwriters Laboratories of Canada), NFPA (National Fire Protection Association): UL 94 HB - Meets UL 94 Flame class, 94 HB. UL File No. E 40195 (N).
      • Mil-Spec (United States Military Standard): A-46146 - MIL-A-46146
    • Brand
      • Dowsil
    Specifications
    Cure Specs
    Cure Temperature (°C) 25, 25, 20 to 25 Room temperature Test Method
    Odor Details Low
    Cure Time (min) 2,160, 10,080, <1,440, <4,320 Test Method
    Viscosity (cPs) NonFlow, Non-slump
    Tack Free Time (min) 30, 15 Test Method
    Bond Strength
    Peel Strength (piw) 25 (ppi) Test Method
    Tensile Strength (psi) 275 Test Method
    Material Resistance
    Ozone Resistance Resistance to ozone
    Non-Corrosive Non-Corrosive
    Environmental Resistance Environmental resistance, Resistance to weathering
    High Temperature Resistance (°C) 177, 204 Test Method
    Low Temperature Resistance (°C) -55 Test Method
    Moisture/Humidity Resistance Resistance to moisture, Humidity resistance
    Other Resistance Resistance to corona
    Conductivity
    Dissipation Factor 8.7e-3 , 2.8e-3 Test Method
    Dielectric Strength (V/mil) 475 Test Method
    Dielectric Constant 3.30, 3.21 Test Method
    Volume Resistivity (O) 7.7e14 (Ohm•cm) Test Method
    Hardness
    Durability Tough, Durable
    Shore A Hardness 35 Test Method
    Elongation (%) 350 Test Method
    Other Properties
    Extrusion Rate 150 (g/min)
    Specific Gravity 1.330 Test Method
    Business Information
    Shelf Life Details When stored at or below 90°F (32°C), DOWSIL 748 Noncorrosive Sealant has a shelf life of 24 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 date of manufacture
    Shelf Life (mon) 24
  • Best Practices for Dow Dowsil 748 Non-Corrosive Sealant

    *See Terms of Use Below

    1. Surface Preparation

      DOWSIL 748 Noncorrosive Sealant forms a bond to most clean surfaces of metals, glass, silicone or organic resins, and vulcanized silicone rubber. A primer is recommended on some plastics such as acrylic

      use DOWSIL™ 1205 Prime Coat.

    2. Application

      Ready-to-use

      Apply DOWSIL 748 Noncorrosive Sealant to the prepared surface in a uniform thickness. 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.

      Best adhesion is obtained with a 15 mil thick glue line

      metal-to-metal bonds should not overlap more than one inch.

    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), DOWSIL 748 Noncorrosive Sealant will cure to a depth of 75 mils. In 72 hours, it will cure to about a 1/4-inch thickness with a Durometer hardness of about 20. Sections 1/2-inch deep can take up to two weeks for complete cure.

      The relative humidity must be at least 20 percent to effect cure in the times stated. Less moisture will extend the cure time.

      If both bonded members are impermeable to moisture, as in the case of two metal plates, cure time will depend on the thickness of DOWSIL 748 Noncorrosive 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.

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    *See Terms of Use Below

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Cure Temperature Test Methods
Cure Temperature Cure Time Test Method
25°C As supplied, 1/8 inch, Specification Writers: These values are not intended for use in preparing specifications.
25°C As supplied, Full cure, 1/8 inch, 50% RH., Specification Writers: These values are not intended for use in preparing specifications.
20 to 25°C Room temperature 50 percent relative humidity
Cure Time Test Methods
Cure Time Test Method
2,160 min As supplied, 1/8 inch, Specification Writers: These values are not intended for use in preparing specifications.
10,080 min As supplied, Full cure, 1/8 inch, 50% RH., Specification Writers: These values are not intended for use in preparing specifications.
<1,440 min 50 percent relative humidity
<4,320 min
Tack Free Time Test Methods
Tack Free Time Tack Free Temperature Test Method
30 min 25°C As supplied, 50% RH, Specification Writers: These values are not intended for use in preparing specifications.
15 min 25°C As supplied, 50% RH, Specification Writers: These values are not intended for use in preparing specifications.
Tensile Strength Test Methods
Tensile Strength Cure Time Cure Temperature Cure Humidity Test Method
275 psi >10,080 min 25°C 50 % ASTM D 412, As cured – physical, Specification Writers: These values are not intended for use in preparing specifications.
Peel Strength Test Methods
Peel Strength Cure Time Cure Temperature Cure Humidity Substrate Test Method
25 (ppi) >10,080 min 25°C 50 % 1/4-inch steel strip to aluminum As cured – physical, Specification Writers: These values are not intended for use in preparing specifications.
High Temperature Resistance Test Methods
High Temperature Resistance Test Method
177°C Service-temperature
204°C Service-temperature
Low Temperature Resistance Test Methods
Low Temperature Resistance Test Method
-55°C Service-temperature
Dielectric Constant Test Methods
Dielectric Constant Temperature Test Method
3.30 25°C ASTM D 150, at 100 Hz, After 7 days at 77°F (25°C) and 50% RH., Specification Writers: These values are not intended for use in preparing specifications., Cured
3.21 25°C ASTM D 150, at 10 kHz, After 7 days at 77°F (25°C) and 50% RH., Specification Writers: These values are not intended for use in preparing specifications., Cured
Dielectric Strength Test Methods
Dielectric Strength Test Method
475 V/mil ASTM D 149, Cured, After 7 days at 77°F (25°C) and 50% RH., Specification Writers: These values are not intended for use in preparing specifications., Cured
Dissipation Factor Test Methods
Dissipation Factor Temperature Test Method
8.7e-3 25°C ASTM D 150, at 100 Hz, After 7 days at 77°F (25°C) and 50% RH. , Specification Writers: These values are not intended for use in preparing specifications., Cured
2.8e-3 25°C ASTM D 150, at 10 kHz, After 7 days at 77°F (25°C) and 50% RH., Specification Writers: These values are not intended for use in preparing specifications., Cured
Volume Resistivity Test Methods
Volume Resistivity Test Method
7.7e14 (Ohm•cm) ASTM D 257, After 7 days at 77°F (25°C) and 50% RH., Specification Writers: These values are not intended for use in preparing specifications., Cured
Elongation Test Methods
Elongation Test Method
350 % ASTM D 412, After 7 days at 77°F (25°C) and 50% RH., Specification Writers: These values are not intended for use in preparing specifications., Cured
Shore A Hardness Test Methods
Shore A Hardness Shore Hardness Test Method Hardness Temperature
35 Durometer, ASTM D 2240, After 7 days at 77°F (25°C) and 50% RH., Specification Writers: These values are not intended for use in preparing specifications. 25°C
Specific Gravity Test Methods
Specific Gravity Temperature Test Method Time
1.330 25°C After 7 days at 77°F (25°C) and 50% RH., As cured – physical, Specification Writers: These values are not intended for use in preparing specifications. >10,080.00 min