DuPont MOLYKOTE High Vacuum Grease

MOLYKOTE High Vacuum Grease is an NLGI Grade 3-4, translucent white grease, used primarily in sealing vacuum and pressure systems.

Formally called Dow Corning High Vacuum Grease or Dow Corning High Vacuum Grease 976V, the name has changed, but not the formulation. The merger and then splitting of the DowDupont companies now have this grease under the DuPont MOLYKOTE line of greases.

MOLYKOTE High Vacuum Grease is a stiff, non-melting silicone lubricating material and has much higher stability at the higher end of the temperature range(-40° C to 200° C), than hydrocarbon greases such as Apiezon® M, However, its initial room temperature pump down characteristics are not as quite as good taking noticeably longer to out-gas. This grease is very popular as a general laboratory lubricant, in large part to its low cost relative to the alternatives. It should not be considered for use on fluorosilicone "O" rings and gaskets.

Applications

Vacuum Applications:
MOLYKOTE High Vacuum Grease is recommended for vacuums reaching between 1x10-5 and 1x10-6 torr. It is recommended that the grease be preconditioned under vacuum and temperature until these limits are reached to avoid sample contamination. Seals and lubricates chemical processing equipment. Lubricating plug valves, control valves, flow meter bearings, ceramic plug cocks, fire extinguisher valves, water treating equipment, synthetic rubber gaskets, and seals in high-temperature applications. Sealing vacuum and pressure systems. Lubricating O-rings in binoculars and telescopes; prevents fogging of delicate lenses.

The MOLYKOTE High Vacuum Grease should not be considered compatible with normal hydrocarbon or perfluorinated polyether pump fluids and since these are the pump fluids normally used in an electron microscope column, we do not recommend this product for the microscope column application. However, it is quite an acceptable choice for use in vacuum evaporators, especially for lubricating the bell jar "O" ring seal except where Si-free carbon-coated grids are being made. Once a vacuum evaporator is "contaminated" with silicone, it is nearly impossible to ever return it to the state of being able to produce silicon-free carbon-coated grids. If you are having this problem with Si contamination of your carbon grids, then consider having SPI Supplies make your grids for you using our custom grid coating program. As is the case for the selection of any component being brought into a vacuum system, the prospective user should be familiar with the product's specifications and properties. Again, as mentioned above, we would not recommend the use of this product in contact with a fluorosilicone "O" ring or gasket.

Other Applications:
Seals and lubricates chemical processing equipment. Lubricating plug valves, control valves, flow meter bearings, ceramic plug cocks, fire extinguisher valves, water treating equipment, synthetic rubber gaskets and seals in high-temperature applications. Sealing vacuum and pressure systems. Lubricating O-rings in binoculars and telescopes; prevents fogging of delicate lenses.

Product Details

Listing Specifications: FDA 21 CFR 175.300     

Limitations

MOLYKOTE High Vacuum Grease is not recommended for use:
In contact with liquid oxygen and should not be used in applications requiring LOX compatibility. For such applications, we recommend the Braycote line of high vacuum greases be considered.

With silicone elastomers. In this case, we would recommend either the hydrocarbon-based Apiezon greases or the Braycote greases.

On surfaces to be painted, it will prevent a good adhesion between the paint coating and substrate. Virtually all greases will have a similar deleterious effect so there is not recommended substitute. If a surface is being prepared for a top coating, care must be taken to prevent contamination from any grease.

As a lubricant in metal bearings, but here again, we would recommend either the hydrocarbon base Apiezon greases or the fluorocarbon-based Braycote greases, depending on the temperature range of us and exposure to reactive chemicals.