Braycote 640AC High Vacuum Grease 2oz (56g)

Braycote 640AC High Vacuum Grease 2oz (56g)
Braycote 640AC High Vacuum Grease 2oz (56g)
AvailabilityIn Stock

Braycote® 640AC High Vacuum Grease 2oz (56g)

Castrol Braycote 640AC is a white, smooth, homogeneous NLGI Grade 2 grease based upon a blend of a perfluoroether base oil and a tetrafluoroethylene telomer. Castrol Fluoroclean™ X100 or Castrol Fluoroclean™ HE can be used to remove this lubricant. Refer to the data sheets for information regarding these products.


Braycote 640AC is designed as an oxidizer and propellant compatible grease suitable for use in aerospace vehicles, spacecraft, rocket and aircraft engines and associated ground support equipment, oxygen equipment, and transport equipment. Braycote 640AC is typically used in the lubrication of threaded fasteners, connectors, valves, gaskets, elastomers and bearings. Perfluorinated greases, in general, exhibit excellent shelf lives due to their intrinsic inertness.


  NLGI Grade 2
D 1403 Penetration, 25°C, mm-1
Worked, 60 strokes
D 2595 Evaporation Loss, % wt
22 hrs @ 204°C (400°F)

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

FTM 5309 Copper Strip Corrosion
72 hrs @ 100°C (212°F)
FTM 5414 Solubility in Fuel 0.48
D 2512 LOX Impact Sensitivity
20 drops, 1100 mm
Base Oil Properties
D 445 Kinematic Viscosity, cSt
@ 99°C (210°F)
@ 38°C (100°F)
@ 0°C (32°F))
D 2270 Viscosity Index 134
D 97 Pour Point, °C (°F) -36 (-30)
D 972 Evaporation Loss, % wt
22 hrs @ 204°C (400°F)
D 972 Evaporation Loss, % wt
22 hrs @ 204°C (400°F)
Knudsen Vapor Pressure, torr
@ 38°C (100°F)
@ 100°C (212°F)
8 x 10-8
2 x 10-3
D 287 Density @ 24°C (75°F), g/mL 1.91

Temperature Range:

-36°C to 204°C (-30°F to 400°F) under normal operating conditions and up to 260°C (500°F) for short durations.


Braycote 640AC is compatible with all commonly used metals, plastics and elastomers. Braycote 640AC may be adversely affected by Lewis Acids such as aluminum chloride, at elevated temperatures. Newly exposed rubbing surfaces of aluminum, magnesium, or titanium alloys may react with Braycote 640AC under certain conditions. 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 high 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 640AC is available in 2 ounce (AVDP) syringes.