Dowsil Silicone Weather Proofing Sealant DS-789-12 - Clear (300 ml) (Pack of 12)

DOWSIL 789 Silicone Weatherproofing Sealant is a one-part, neutral- cure, architectural grade sealant. It easily extrudes in any weather and cures at ambient temperature by reaction with moisture in the air to form a durable, flexible silicone rubber seal.

Features & Benefits:

• Easy of use - all temperature gunability
• Primerless adhesion - upon curing will form a strong bond to most common building components without the use of a primer
• Long-life reliability - cured sealant stays elastomeric from -50°C to 150°C without hardening, cracking or becoming brittle under normal weather conditions
• Low Modulus - with extension/compression capability up to ±50% of original joint width
• Excellent weatherability, virtually unaffected by sunlight, rain, snow, ozone
• Ease of application - ready to use as supplied

Composition:

• One-part, neutral-cure, RTV silicone sealant

Properties:

• Adhesion to - Anodized Aluminum, Concrete, Enamelled and Reflective Glass, Fluorocarbon Coated Aluminum, Glass, Heat Strengthened Glass, Low E Coated Glass, Metal Panels, Polyester Powder Coated Aluminum/Steel, Stainless Steel
• Appearance - Opaque, Translucent
• Chemistry - Neutral
• Color - Black, Bronze, Clear, Green (Catalyst), Grey, Ivory, White
• Cure System - 1-Part Cure
• Flow - NonSag
• Movement - Medium
• Substrate - Non-porous
• Where Used - Job Site

Typical Properties:

• Uncured - As Tested at 50% RH and 23°C (73°F)
  • Working Time : 15-30 minutes
  • Tack-free Time, 77°F, 50% RH : <80 minutes
  • Curing Time at 77°F (25°C) and 50% RH : 7-14 days
• As Cured - After 21 days at 50% RH and 77°F (25°C)
  • Ultimate Tensile Strength : 16 kg/cm2
  • Ultimate Elongation : 700 %
  • Joint Movement Capability : ±50 %
  • Tear Strength, die B : 11 kg/cm

Application:

• DOWSIL 789 Silicone Weatherproofing Sealant is a specified, premium performance weather sealing product specifically designed for general glazing and weather sealing in curtain wall and building facades.

How to Use:

• 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.
• Application Method -
  • Install backing material or joint filler, setting blocks, spacer shims and tapes. Mask areas adjacent to joints to ensure neat sealant lines. Primer is generally not required on non-porous surfaces, but maybe necessary for optimal sealant of certain porous surfaces. A test placement is always recommended.
  • Apply DOWSIL 789 Silicone Weatherproofing Sealant in a continuous operation using a positive pressure. (The sealant can be applied using many types of air-operated guns and most types of bulk dispensing equipment.) Before a skin forms (typically within 15~20 minutes), tool the sealant with light pressure to spread the sealant against backing material and the joint surfaces. Remove masking tape as soon as the bead is tooled.

Handling Precautions

• Product safety information required for safe use is not included in this document. Before handling, read product and container labels for safe use, physical and health hazard information.

Limitations:

DOWSIL 789 Silicone Weatherproofing Sealant is not approved for use as a structural sealant. It should not be used:

• In below-grade applications
• When surface temperatures exceed 50°C (122°F)
• On surfaces that are continuously immersed in water
• On building materials that bleed oils, plasticizers or solvents, green or partially vulcanized rubber gaskets or tapes
• On frost-laden or wet surfaces
• In totally confined joints (the sealant requires atmospheric moisture for cure)
• If the sealant is intended to be painted (paints do not typically adhere to most silicone sealants)
• To surfaces in direct contact with food or other food-grade applications

This product is neither tested nor represented as suitable for medical or pharmaceutical uses.

Usable Life And Storage:

• When stored at or below 30°C (86°F) in the original unopened containers, DOWSIL 789 Silicone Weatherproofing Sealant has a usable life of 12 months from the date of manufacture. Refer to product packaging for Use By date"".