Foster® Sealfas G-P-M® Mastic 35-00™

• Foster® Sealfas G-P-M® Mastic is a high solids, water-based, general purpose mastic having excellent trowel and spray properties.
• G-P-M® is used for the protection of thermal insulation and hard, dry cement coats, both indoors and outdoors.
• Sealfas G-P-M® Mastic is fire-resistive and features ease of application, non-flammability, non-toxicity, mild odor, insulation compatibility, good package stability, plus excellent outdoor durability.
• Sealfas G-P-M® Mastic meets NFPA 90A & 90B 25/50 requirements.
• Sealfas G-P-M® Mastic is produced under the classification and follow-up service of Underwriter's Laboratories, Inc. Nuclear Grade
• Sealfas G-P-M® Mastic 35-00Q can be supplied to meet the stress corrosion and chemical analysis requirements of MIL-I-24244C or nuclear regulatory guide 1.36 on special order.
• Sealfas G-P-M® Mastic 35-00 meets the requirements of:
  • MAS Certified Green®
  • California Dept. of Public Health Standard Method v1.2
  • VOC Emissions and Content requirements to contribute to LEED v4 EQ Credit: Low Emitting Materials – Paints and Coatings

Preparation

• Do not thin.
• Foster® Sealfas G-P-M® Mastic will appear to be thick, but this is a "false" consistency which "breaks down" readily on application.
• Stirring is not necessary. Apply only to clean, dry, oil-free surfaces.
• Keep container closed when not in use.

Application – heavy duty, hot and dual temperature service

• Follow flashing recommendations when installed outdoors.
• For best results, prime hygroscopic alkaline cements with Foster® 32-22 Protektor® Sealant or Foster 81-42W LAGFAS® Adhesive/Coating diluted 50% with water to lock down dusty surfaces.
• Both the cement and the primer must be completely dry before the Foster® Sealfas G-P-M® Mastic is applied.

MAST-A-FAB® Reinforcement

• Apply a tack coat of Foster® Sealfas G-P-M® Mastic at a thickness of 1/32 inch (0.8 mm).
• This is equivalent to 2 gal./100 sq. ft. (0.8 l/m2 ). Embed Foster® Mast-A-Fab® white membrane into wet tack coat.
• Smooth membrane to avoid wrinkles and overlap all seams at least 2 inches (5 cm).
• Apply a finish coat of Foster® Sealfas G-P-M® Mastic at a minimum thickness of 1/16 inch (1.6 mm).
• This is equivalent to 4 gal./100 sq. ft. (1.6 l/m2 ).
• This finish coat shall be applied no later than 1/2 hour after the tack coat and shall completely cover the membrane.
• This application shall provide a minimum dry film thickness of 62 mils (1.6 mm).

Heavy duty applications – up to 50% greater tensile strength

• Apply as above, substituting Childers™ Chil-Glas® #5 as the reinforcing membrane.
• Note that the membrane weave pattern will show through the dried mastic.

Trowel

• Use clean steel trowel.
• Apply in full thickness promptly.
• Avoid excessive troweling.

Brush

• Use a good brush (suitable for water-based paints), making strokes as long as possible over the surface.
• Apply with full brush and spread out evenly.
• Do not overwork.
• Multiple coats will be needed to achieve the minimum dry film thickness.

Spray

• Foster® Sealfas G-P-M® Mastic (45-00™ series) may be spray applied with heavy duty pneumatic airless equipment.
• For spray equipment information, please consult Airless Spray Recommendations or contact your spray equipment supplier.
• Average viscosity range: 60,000 – 100,000 cps.
• Corrosion resistant pumps and fittings are suggested.

• Use fresh water to clean equipment before product dries.
• Dry product may be removed with hot soapy water or solvents such as chlorinated solvent (non-flammable) or xylol (flammable).

• Store and apply between 40°F (4°C) and 100°F (38°C), protect from freezing until dry.
• To resist rain washoff, allow at least 16 hours drying time above 40° F (4°C), with a relative humidity of 50%.
• Higher humidity at lower temperatures may retard drying. Always test paper facings for acceptable adhesion before using.
• Outdoor horizontal surfaces must always drain completely.
• A pitch of at least 1/2 inch per foot (4 cm/m) is recommended.
• Always select Foster® Sealfas G-P-M® Mastic 35-00/45-00™ white for use over polystyrene insulation installed outdoors.