Foster® 60-25 C.I. Mastic is a high solids, asphalt cutback mastic with excellent vapor retarder properties and low vapor permeance. It is a black, trowel-applied mastic primarily used for vapor barrier and adhesive applications in construction, especially for insulation systems.

Specifications and Properties

• Color: Black
• Application Consistency: Trowel
• Average Weight/U.S. Gallon (ASTM D1475): 9.4 to 10.0 lbs. (1.13 to 1.20 kg/l)
• Material Preparation: Do not thin; apply only to clean, dry, oil-free surfaces
• Application Method: Cannot be applied by spray; use trowel for application
• Drying Time: 1/2 to 6 hours to set to touch, 7 days to dry through (at 73°F and 50% RH)
• Water Vapor Permeance:
  • ASTM E96 Procedure A: < 0.015 perms at 1/8 inch dry film thickness
  • ASTM F1249: 0.02 perms at 1/8 inch dry film thickness
• Average Non-Volatile (ASTM D2369): 66% by volume (76% by weight)
• Coverage Range: 12 gallons per 100 sq. ft. (4.9 l/m2) for a 0.192 in. wet film thickness on smooth non-porous surfaces; higher gallonage required for porous or rough surfaces
• Service Temperature Limits: -40°F to 180°F (-40°C to 82°C)
• Wet Flammability: Flash Point at 104°F (40°C)
• Surface Flame Spread (ASTM E162): Flame Spread 145 when applied to 1/4 inch inorganic reinforced cement board

Features and Application

• Vapor Retarder: Effective for preventing water vapor entry into insulation on heated lines, vessels, and equipment.
• Use with Insulation: Ideal for low temperature insulation on outdoor applications.
• Heavy Duty Service: Can be used for outdoor and heavy-duty applications with appropriate preparation and application methods.
• Compatibility Testing: Necessary for foil and paper facings, and plastic materials.
• Weathering: May weather to a dark gray color; ensure proper drainage on outdoor horizontal surfaces.

Key Data and Facts

• Usage Limitations: Not to be used on polystyrene foam.
• Flame Spread Variability: May vary based on product thickness and the surface it's applied over.
• Decorative Coating Application: Allow a minimum of 30 days drying time before application.
• Tack Coat Application: For heavy duty service, apply a tack coat at 1/16 inch (1.6 mm) thickness, equivalent to 4 gallons per 100 square feet.

Notes

• This product is designed for industrial use and should be applied following specific guidelines as mentioned in the product data sheet and safety data sheet.