Braycote 631A 1 pound

This item is no longer available. We suggest SPI# 05164-XQ Castrol Braycote 631RP.

Castrol Braycote 631A is a smooth, buttery, translucent white NLGI #2 grease, based upon a perfluoroether oil. This grease is nonflammable and is in general chemically inert. It is thermally stable either alone or in the presence of oxygen, has exceptionally low volatility, and little tendency to form deposits. Castrol Fluoroclean™ X100 and Castrol Fluoroclean™ HE can be used to remove this lubricant. Refer to the data sheets for information regarding these products.


Braycote 631A is used in gears, ball and roller bearings, electrical contacts, and as thread and elastomer lubricant. It is particularly useful as a lubricant in corrosive or oxygen (LOX/GOX) service and as a plug valve lubricant. This product is compatible with concentrated acids and bases and it does not hydrolyze or oxidize. Perfluorinated greases, such as Braycote 631A, exhibit excellent shelf lives due to their inertness.



D 1403 Penetration @ 25°C (77°F), mm-1
Worked, 60 strokes

FTM 5309 Copper Strip Corrosion
24 hrs @ 100°C (212°F)

D 2595 Evaporation Weight Loss, % wt
22 hrs @ 204°C (400°F)

FTM 321 Oil Separation, % wt
30 hrs @ 204°C (400°F)

FTM 5415 Water Washout, % wt
1 hr @ 38°C (100°F)

D 2512 LOX Impact Sensitivity
20 drops, 1100 mm

D 2266 Four-Ball Wear-Test, AWSD, mm
1200 rpm, 40 kgf, 1 hr, 75°C (167°F)

D 1478 Low-Temperature Torque, @ -54°C (-65°F)
Running, 1 hr

D 2265 Dropping Point, °C (°F)
182 (360)
Base Oil Characteristics:
Knudsen Vapor Pressure, torr
@ 20°C (68°F)
@ 100°C (212°F)

<9 x 10-7
<9 x 10-4
D 287 Specific Gravity @ 20/20°C (68/68°F)
D 445 Kinematic Viscosity, cSt
@ 99°C (210°F)
@ 20°C (68°F)

D 2270 Viscosity Index
D 97 Pour Point, °C (°F)
-36 (-30)

Temperature Range:

-30°C to above 204°C (22°F to above 400°F).


Braycote 631A is insoluble or at most sparingly soluble in current fuels and oxidizers in propellant service, and in most organic solvents and materials other than fluorinated solvents. It is compatible with all commonly used metals, plastics, and elastomers. This product may be adversely affected by Lewis Acids, such as aluminum chloride, at elevated temperatures. Rubbing surfaces of aluminum, magnesium or titanium under certain conditions may react causing thermal degradation to the lubricant. Such systems should be thoroughly evaluated. Surfaces must be well cleaned of organic rust inhibitors prior to grease application to insure proper lubrication. This product is not recommended for use in applications under vacuum with loads exceeding 100,000 psi for extended periods of time.

Removal of unwanted grease from grease applied surfaces:

The composition of this product is a mixture of small PTFE particles (which won't dissolve in anything) and a perfluorinated polyether liquid. We have found that Castrol® Fluoroclean™ HE is an effective solvent for the liquid component of the formulated composition and aids in the removal of the grease from places where it is no longer needed or wanted.


Braycote 631A is packaged in 1 pound jars.