The release of base oil from the thickener structure. Some bleed is the whole point, because that oil is what actually lubricates the rolling contacts. Too much in storage leaves a puddle on top of the pail or cartridge, and too much in service leaves a dry, hard crust behind. Oil separation is measured with static tests such as ASTM D1742 and D6184 and rises with low-viscosity base oils, heat and soft grades.
Every cartridge off that pallet has oil bleed pooled on top, they sat in the hot shed all summer.
Also heard as
- oil bleed
- oil separation
- bleeding
Related terms
Grease
Semi-solid lubricant made of oil held in a thickener sponge, usually with additives.
Thickener
Solid structure in a grease, usually a metal soap or polyurea, that holds the base oil like a sponge.
Channeling
Grease pushed aside by rolling elements so it sits in shoulders beside the track instead of churning.
NLGI grade
Number from 000 to 6 describing grease stiffness, based on cone penetration after working.
Same word, different worlds
To let trapped air out of a hot water radiator, baseboard or high point by opening its small vent until water appears.
Sealants & WaterproofingStaining from fluids or plasticizers that migrate out of a sealant into porous stone or masonry.
Vacuum EngineeringTo admit a small, controlled flow of gas into a vacuum system through a needle or leak valve.