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
Composition |
A pyrobituminous resin processed by homogenization with inhibitive pigments and aromatic solvents. |
Color |
Black |
Volume Resistivity |
2.12 x 1013 ohm cm3 |
Application Temperature |
32°F to 120°F |
Service Temperature |
0 to 250°F |
Shelf Life |
At least one year |
Weight per Gallon |
9.42 lbs |
Specific Gravity |
1.13 |
Percent Solids: |
|
Flash Point |
44°F Seta Closed Cup |
Application
- Apply the wrap and then put on a second coat of Royston Roskote R28 Rubberized Mastic.
- Apply the second coat of Royston Roskote R28 Rubberized Mastic and then wrap use either while the Royston Roskote R28 Rubberized Mastic is still wet or after it has dried to the touch. Wrap tightly to embed the mesh in the coating.
Pump |
Graco 8:1 ratio minimum or equivalent. |
Hose: |
|
Gun |
Heavy material gun |
Spray Tips |
3/16" minimum. External Win Air Cap |
Pressure |
Will vary wit temperature and pump output ratio, 50-90 psi material pressure is normal. Atomization pressure 40-80 lbs. |
Airless Spray |
Pump |
Graco Bulldog or equivalent. Pump must be capable of an output of three gallons per minute. |
Hose |
Material hose 1 /2" minimum, for lengths over 25 feet use 3/4" ID. Use high pressure, wire braid hose. |
Gun |
Use mastic type airless spray gun, Graco Hydra mastic Gun or equivalent. |
Spray Tip |
.031" maximum |