MOLYKOTE® High-Vacuum Grease – Silicone Vacuum Sealant and Lubricant for Valves, O-Rings and Vacuum Systems 50Gm Tube

MOLYKOTE® High-Vacuum Grease is a silicone-based lubricating and sealing compound engineered for vacuum systems, chemical processing equipment, and high-temperature sealing applications. The grease consists of silicone oil and an inorganic thickener, forming a stiff, non-melting compound that provides reliable lubrication and sealing under demanding operating conditions.
This high-vacuum grease features low volatility and strong resistance to water, chemicals, and temperature fluctuations, making it suitable for sealing and lubricating equipment operating under vacuum or pressure. The formulation reduces wear in plastic-to-metal and rubber-to-metal contact surfaces while maintaining stable lubrication performance over extended service periods.
MOLYKOTE High-Vacuum Grease is widely used for lubrication and sealing of plug valves, control valves, ceramic plug cocks, flow meter bearings, and fire extinguisher valves. It is also suitable for sealing vacuum and pressure systems in chemical processing plants and industrial equipment. The compound is commonly applied to synthetic rubber gaskets, seals, and O-rings operating at elevated temperatures or in chemically aggressive environments.
The grease is also used in optical equipment such as binoculars and telescopes to lubricate O-rings and prevent lens fogging caused by moisture ingress. Its excellent chemical stability and resistance to common gases and aqueous solutions make it a reliable sealing and lubrication solution for vacuum technology and precision equipment.
Key Selection Proof Points
Chemical type: Silicone oil with inorganic thickener
Appearance: White to gray translucent compound
Consistency: Stiff, non-melting grease
Penetration (unworked): 170–230 mm/10
Penetration (worked 60): <260 mm/10 Bleed (24 hr at 200°C): <0.5% Evaporation (24 hr at 200°C): <2.0% Melting point: None (non-melting compound) Key properties: low volatility, chemical resistance, water resistance, vacuum sealing capability Typical applications: vacuum systems, plug valves, control valves, O-rings, synthetic rubber gaskets, chemical processing equipment, optical instrument seals