Foster® Air-FAS™ Duct Sealant 32-18

• Air-FAS™ Duct Sealant may be pressure tested after 16 – 24 hours dry time above 70oF (21oC). It quickly forms a strong bond to clean galvanized, aluminum and mild steel metal ducts.
• Air-FAS™ Duct Sealant can also be used to seal ASJ, FRK and FSK jackets and board facings at joints and laps and for sealing flexible air ducts to rigid connectors.
• Air-FAS™ Duct Sealant will meet all SMACNA pressure classes up to 10" w.g. and SMACNA seal classes A, B and C on ducts constructed to SMACNA standards. It has been tested up to 15" w.g. and passed with no sealant blow out.

Material Preparation
DO NOT THIN. Apply only to clean, dry, oil-free surfaces. Keep container closed when not in use.
Application
UL 181B MASTIC CLOSURE OF UL 181 FLEXIBLE AIR DUCTS: Apply to clean, dry, oil-free surfaces by brush, trowel or power extrusion. Uniformly brush out a 2” wide coat over the joint, at the nominal rate of 80 sq. ft./gal. (2.0 m²/l). Allow the completed joint to dry at least 48 hours above 70°F before pressure testing. High humidities (over 70%) and/or cooler temperatures may retard drying. Total wet film thickness to be 20 mils (0.5 mm).
Other Sealing Applications - NOT UL 181:
Apply a continuous film of Air-FAS™ Duct Sealant over all areas of the duct system where air leakage may occur. A brush may be used to work the sealant into joints and remove excess. On spiral ducts, apply a coat of duct sealant to the male end of the coupling prior to fitting the straight run of spiral duct over it. Brush excess sealant over the joint to complete the seal. Screw holes and flanges should also be sealed with a coat of duct sealant. It may be applied to the inside or the outside of the duct.
Power Extrusion

Air-FAS™ Duct Sealant may be applied using a wide variety of power (pressure) extrusion equipment suitable for use with water- based sealants. It is a soft buttery gel with a typical viscosity range of 90,000 - 140,000 cps. Corrosion resistant pumps and fittings are suggested.
Top Coating
After it is completely dry, Air-FAS™ Duct Sealant may be top coated with good quality water-based paint.
Clean Up
Use fresh water to clean brushes and equipment before product dries. Dry product may be removed with hot soapy water or strong solvents such as chlorinated solvent (non-flammable) or xylol (flammable).

• To resist rain washoff, allow at least 16 hours drying time above 40°F, with a relative humidity of 50%. Higher humidity or lower temperatures may retard drying.
• Always test foil and paper facings for acceptable adhesion.
• If used between impermeable surfaces, drying time will be extended.

¹ - Tested at coverage rate of 45 sq. ft. per gal. in a 2 inch (51 mm) wide strip. Applied to 1/4 inch (6.4 mm) inorganic reinforced cement board. The flame spread may vary at different product thicknesses and/or when applied over other surfaces.