Dow Corning Vacuum Grease
Vacuum grease is a lubricant with low volatility and is used for applications in low pressure environments. In addition to being a lubricant, vacuum grease can also be used as a sealant for joints in vacuum systems. This is usually limited to soft vacuums, as ultra high vacuum or high temperatures may create problems with the vacuum grease outgassing. Dow corning grease should be used in conjunction with glassware to create an airtight seal whenever required.