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To protect the surface of above grade masonry from spelling, cracking, efflorescence and other types of damages by water penetration.

To avoid the above difficulties by preventing the ingress of moisture from the out side suppressing the outward transport of moisture NARSIL-77 satisfies these conditions ideally.

NARSIL-77 is a water dilutable solution, designed to impart water repellency to a wide variety of surfaces and materials.

On application of the dilute solution and after the water has evaporated, NARSIL-77 solidly reacts with moisture and carbon dioxide in the air to form an insoluble invisible and water repellent silicone film within 24 hours.

NARSIL-77 treatment improves the wall strength of high absorption brick, at low but still effective concentration. The face of the brick can be even treated to reduce rate to zero. Water leakage through walls is completely prevented by reducing the suction rate of brick to a level under 20 grams per minute before the bricks are laid.

Sp. Gravity
Light Straw
PH Value
12 – 13
Flash Point
Solvent ( Thinner)

Preparing Water Repellent

NARSIL-77 is usually diluted to a concentration of about 3% solid just prior to application. To prepare a 3% solution, mix 1Kg. of NARSIL-77 as received with 9 Kg. of water.

This 10Kg. solution will cover 225 to 450sq. ft. depending on the porosity of the surface.

Method of Application and curing

Water repellent based on NARSIL-77 may be applied by Dipping, Brushing or Spraying. When spraying should not be atomized or misted, but flowed on in a solid stream, with the spray gun held to a distance just enough to eliminate foaming on the masonry surface. The run down of six to twelve inches should be maintained, and generous overlapping of passes is recommended.

After application of NARSIL-77 solution, the treated surface should be allowed to dry at least 24 hours to develop maximum water repellency. This interval may be shortened some what by force drying at temperature to 300°F. Until the reaction is complete the applied film still remains water soluble and any rain falling during this time can wash it out, at least partly. Causing non-uniform water repellent effect. So dry weather, or at least the absence of rain and fog should be preferred for out door application.



* Concrete to increase durability by improving resistance to effects of freeze-thaw exposure.

* For manufacturing natural stone to reduce efflorescence, keep surface clean, and improve resistance to effect of weathering.

* Coating for roofing granules to provide stain resistance, to improve adhesion to asphalt.

* Coating for glass beads to provide better flow under wet condition and to improve adhesion.

* Coating for various asbestos product including insulation shingles to reduce water absorption.

* Coating for concrete glaze and decorative title to seal against moisture.


* As dispersing agent in clays or ceramics to reduce water requirement and improve green strength.

* Latex, cement base paint, starches, pipe insulation and wall board to improve water rellency.

* Binder in foundry sand cores to give greater moisture stability to cores and improve green strength (before firing)

* Primer for latex paint and ceramic tile to give stronger more water resistant adhesion.

* Concentration used as an additive as low as 0.1% based on the weight of solid materials.

*Optimum water repellency is usually developed with 0.1 to 1.0% concentration.


NARSIL-77 should be handled with the same precaution as dilute solution of caustic soda.

Always apply in a liquid stream, not by misting or fogging. If misting should occur, avoid inhalation. Contact with the eyes or skin should be treated immediately flooding the area with large quantities of water for at least 15 minutes, for eyes or respiratory contact, obtain medical attention.

NARSIL-77 is added to Acrylic Emulsion paints or oil bound distemper preparation to yeiled water repellent painted surfaces.