The Dow Corning High Vacuum Grease is not 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 from either grease or diffusion pump fluid, 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.
The grease also finds wide application for the lubrication of water-treating equipment and general laboratory equipment even for non-vacuum applications. It is used for the lubrication of "o" rings on binoculars and telescopes, and is also used to prevent fogging on delicate lenses and mirrors.
FDA 21 CFR 175.300
Securing or including complete information on variables such as pressure, flow velocity, relubrication schedules and valve construction is impractical. For the reason the suitability of Dow Corning High Vacuum Grease should always be tested before the material is adopted for regular use.When stored under normal warehouse conditions, Dow Corning High Vacuum Grease has a shelf life of 60 months from date of manufacture. Refer to the product packaging for the "use by" date.Dow Corning High Vacuum Grease is not recommended for use:In contact with liquid oxygen and should not be used in applications requiring LOX compatibility.