Roskote R28 Rubberized Mastic by Royston

Roskote R28 Rubberized Mastic by Royston
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Royston Roskote R28 Rubberized Mastic

Royston Roskote R28 Rubberized Mastic is a cold-applied coating with high electrical resistivity designed to protect underground steel pipes, tanks and other structures against corrosion.

Royston Roskote R28 Rubberized Mastic bonds firmly to clean steel surfaces without use of a primer and also to coal tar and hot applied asphalt. It forms a thick, tough coating which will not oxidize, craze, alligator, crack, check, loosen or scale. It provides a high degree of electrical resistivity and shows excellent performance in cathodic protection or stray current situations. It withstands soil stresses and resists attack by alkalis, acids, salts and moisture.

Royston Roskote R28 Rubberized Mastic should be used as a general purpose coating for underground protection of all fabricated steel products, such as pipes, conduits, valves, fittings, tanks, hydraulic cylinder castings and structural steel. For field coating joints of mill coated pipe, it can be used in conjunction with reinforcing fabric such as Royston Glas-Wrap.

In certain areas in or near petroleum refineries, gasoline bulk plants, service stations, oil producing fields and similar locations, Roskote A-51 Plus which is resistant to both oil and gasoline should be used.

How to Use It

  • Handling Precautions: Royston Roskote R28 Rubberized Mastic is a solvent based material which should be kept away from heat or open flame and should be used only with adequate ventilation. Repeated or prolonged contact with the skin should be avoided.
  • Surface Preparation: Surfaces should be dry for maximum adhesion. Remove rust, scale, soil, mud, oil, grease and other contaminants in the field by wire brushing. Sandblasting or chemical treatment may be more convenient for in-plant surface preparation. No adhesive is required except on newly galvanized surfaces which should be coated with a suitable phosphate wash primer prior to mastic application.
  • Stirring: Royston Roskote R28 Rubberized Mastic should be stirred thoroughly before using.
  • Thinning: Thinning is not required except for cold spray at temperatures below 60°F. If excess thickening occurs because of solvent evaporation from opened containers, original viscosity may be restored by adding Royston Thinner 11 (Toluene).
  • Application: Royston Roskote R28 Rubberized Mastic is applied cold by brush, spray, flow coat, dip or rubber glove. Apply two coats of Royston Roskote R28 Rubberized Mastic at the proper thickness, allowing the first coat to dry to the touch before applying the second.