Dow 791 Silicone WeatherpRoofing Sealant

Dow 791 Silicone WeatherpRoofing Sealant Datasheet
  • Description for Dow 791 Silicone WeatherpRoofing Sealant

    Excellent weatherability, unprimed adhesion, rheology, low string upon gunning; meets global standards; compatible with all Dow Corning sealants.

    *See Terms of Use Below

    Application Type Seal, Bond
    1 Part or 2 Part 1 Part
    Material Form Paste
    Substrate Anodized coated aluminum, Copper, Non-porous, Porous, Coated glass, Galvanized steel, Mortar, Galvanized steel, Glass
    Manufacturer Dow Corning
    Chemistry Silicone
    Cure Method Moisture
    Cure Temperature (°C) 23, 23, 23
    Cure Time (min) 10,080 to 20,160, >10,080, >40,320
    Color Black, Gray, Limestone, Precast white, Bronze, Limestone, White
    High Temperature Resistance (°C) 150, 50
    Low Temperature Resistance (°C) -25, -50
    Key Specifications ASTM (American Standard Test Method): C 920: ASTM C- 920 Type S, Grade NS, Class 50, Use NT, M, G, A; Meets the requirements of ISO 11600 F&G-25LM, ASTM C- 920 Type S, Grade NS, Class 50, Use NT, M, G, A; Meets the requirements of ISO 11600 F&G-25LM
  • Technical Data for Dow 791 Silicone WeatherpRoofing Sealant

    Overview
    • Application Type
    • 1 Part or 2 Part
      • 1 Part or 2 Part - 1 Part
    • Material Form
      • Paste
    • Substrate
      • Non-Porous Substrates - Non-porous
      • Porous Substrates - Porous
      • Glass - Coated glass
      • Aluminum - Anodized coated aluminum
      • Copper
      • Galvanized - Galvanized steel
      • Galvanized Steel
      • Stone - Mortar
      • Other - Masonry
    • Industry
    • Chemistry
    • Cure Method
      • Moisture
    • Color
      • Black
      • Gray - Limestone
      • Off-White - Limestone
      • White - Precast white
      • Yellow - Bronze
    • Key Specifications
      • ASTM (American Standard Test Method) - ASTM C- 920 Type S, Grade NS, Class 50, Use NT, M, G, A; Meets the requirements of ISO 11600 F&G-25LM
      • ASTM (American Standard Test Method): C 920: Class 50 - ASTM C- 920 Type S, Grade NS, Class 50, Use NT, M, G, A; Meets the requirements of ISO 11600 F&G-25LM
    Specifications
    Cure Specs
    Application Temperature (°F) -13 to 122
    Cure Temperature (°C) 23, 23, 23 Test Method
    Cure Time (min) 10,080 to 20,160, >10,080, >40,320 Test Method
    Tack Free Time (min) 35 Test Method
    Work / Pot Time (min) 15 Test Method
    Thixotropic Thixotropic
    Bond Strength
    Tensile Strength (psi) 120 Test Method
    Material Resistance
    High Temperature Resistance (°C) 150, 50
    Low Temperature Resistance (°C) -25, -50
    Hardness
    Shore A Hardness 30 Test Method
    Elongation (%) 460 Test Method
    Flexibility Flexible
    Modulus (psi) Low, Medium, 70, 40 Test Method
    Other Properties
    Specific Gravity 1.520 Test Method
    Business Information
    Shelf Life Details When stored at or below 30°C (86°F) in the original unopened containers, Dow Corning 791 Silicone Weatherproofing Sealant has a usable life of 12 months from the date of manufacture. Refer to product packaging for “Use By” date.
    Shelf Life Type From date of manufacture
    Shelf Life (mon) 12
    Not Good For
    Don't Use With Non-porous, Building materialsthat bleed oils, Plasticizers, Solvents –materials such as impregnated wood, oil-based caulks, Green or partially vulcanized rubber gaskets or tapes
  • Best Practices for Dow 791 Silicone WeatherpRoofing Sealant

    *See Terms of Use Below

    1. Surface Preparation

      Clean all joints removing all foreign matter and contaminants such as grease, oil, dust, water, frost, surface dirt, old sealants or glazing compounds and protective coatings.

    2. Application

      Dow Corning® 791 Silicone Weatherproofing Sealant is a specified, premium performance weathersealing product specifically designed for general glazing and weathersealing in curtain wall and building facades.

      Install backing material or joint filler, setting blocks, spacer shims and tapes. Areas adjacent to joints may be masked to ensure neat sealant lines. Primer is generally not required on non-porous surfaces. On porous surfaces, Dow Corning recommends that a test sample be carried out prior to application. To confirm optimum adhesion on either a porous or nonporous surface, adhesion testing should always be carried out prior to the commencement of any project. Please contact your local Dow Corning Sales Application Engineer for specific advice.

      Apply Dow Corning 791 Silicone Weatherproofing Sealant in a continuous operation using a positive pressure. Tool the sealant with light pressure to spread the sealant against backing material and the joint surfaces before a skin forms. The applied sealant should be tooled within 15 minutes or before a cured skin forms. Remove masking tape as soon as the bead is tooled.

  • Comparable Materials for Dow 791 Silicone WeatherpRoofing Sealant

    *See Terms of Use Below

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Cure Temperature Test Methods
Cure Temperature Cure Time Test Method
23°C At 50% RH and 23°C 73°F
23°C As Cured – After 7 days at 50% RH and 23°C (73°F)
23°C As Cured – After 28 days at 50% RH and 23°C (73°F) – 12 x 12 x 50 mm T.A. joint
Cure Time Test Methods
Cure Time Test Method
10,080 to 20,160 min At 50% RH and 23°C 73°F
>10,080 min As Cured – After 7 days at 50% RH and 23°C (73°F)
>40,320 min As Cured – After 28 days at 50% RH and 23°C (73°F) – 12 x 12 x 50 mm T.A. joint
Tack Free Time Test Methods
Tack Free Time Tack Free Temperature Test Method
35 min 23°C ASTM C 679, At 50% RH and 23°C 73°F
Work / Pot Time Test Methods
Work / Pot Time Test Method Temperature
15 min CTM 98B, At 50% RH and 23°C 73°F 23°C
Tensile Strength Test Methods
Tensile Strength Cure Time Cure Temperature Cure Humidity Test Method
120 psi >40,320 min 23°C 50 % After 28 days at 50% RH and 23°C (73°F) – 12 x 12 x 50 mm T.A. joint (ISO 8339) [0.5 x 0.5 x 2 inch T.A. joint (ASTM C 1135)]
Elongation Test Methods
Elongation Test Method
460 % After 28 days at 50% RH and 23°C (73°F) – 12 x 12 x 50 mm T.A. joint (ISO 8339) [0.5 x 0.5 x 2 inch T.A. joint (ASTM C 1135), Ultimate elongation at break
Modulus Test Methods
Modulus Test Method
Low Modulus Test Method
Medium Modulus Test Method
70 psi at 100% Elongation, After 28 days at 50% RH and 23°C (73°F) – 12 x 12 x 50 mm T.A. joint (ISO 8339) [0.5 x 0.5 x 2 inch T.A. joint (ASTM C 1135)
40 psi at 25% Elongation, After 28 days at 50% RH and 23°C (73°F) – 12 x 12 x 50 mm T.A. joint (ISO 8339) [0.5 x 0.5 x 2 inch T.A. joint (ASTM C 1135)]
Shore A Hardness Test Methods
Shore A Hardness Shore Hardness Test Method Hardness Temperature
30 ASTM D 2240, After 7 days at 50% RH and 23°C (73°F) 23°C
Specific Gravity Test Methods
Specific Gravity Temperature Test Method
1.520 23°C CTM 97B