What is the difference between liquid and solid lubricants?
A solid lubricant such as PTFE creates a permanent boundary layer between moving parts, and almost eliminates start-up friction.
Within a machine, lubricated parts float on a boundary layer of fluid – an oil – and this is called hydrodynamic lubrication. But when the machine stops, these parts settle and this boundary layer is compromised or even eliminated, often leaving metal-to-metal contact. This creates extreme start-up friction when the machine is brought back into service. Solid lubricants help reduce this friction.
Hydrodynamic lubrication can also be compromised at higher temperatures and in exposed areas. Both these scenarios benefit from the addition of solid lubricants.
What is PTFE lubricant?
Poly Tetra Flouro Ethylene (PTFE lubricant) has the third lowest coefficient of friction (COF) known to man, 0.05, which is similar to wet ice on wet ice. It has a bearing structure which can be sized to suit the application (imagine walking across a floor of marbles).
PTFE can be dispersed within a medium weight oil.
Ecopoint Laboratories’ PTFE bearings are very small and uniform to suit high speed lubrication on smooth surfaces.
PTFE lubricant’s incredible characteristics mean that it is the only known surface to which a gecko cannot stick. It is also used as an ant barrier.
Is graphite a solid lubricant?
Graphite has a reasonable COF at 0.5-0.8, but is not easily dispersed in a medium weight oil, so tends to be restricted to greases. It has a lamellar structure (imagine walking across freshly scattered playing cards). Graphite is used in high temperature applications, such as glass manufacture, and in some high torque applications.
What is Mos2?
MoS2 (moly) is a grease additive used in general applications. It is messy in use, but very effective against friction and wear.