Static Oil Bleed
What does it mean static oil bleed?
Static bleeding is the release of the base oil from the grease thickener in the container in which it has been placed or in a non-moving part in which it has been placed.
Static bleeding occurs naturally in all types of greases, the proportion, however, depends on their composition. Moreover, Bleeding can be affected by storage conditions:
- storage temperature
- duration of storage
- vibration to which the container may be exposed
- an uneven grease surface in the container
- the natural force of gravity.
These factors can cause extremely weak stresses to be placed on the grease, resulting in the release of small amounts of base oil.
Static bleeding is more pronounced if:
- the grease is a soft consistency grease (NLGI grades 00, 0 and 1)
- base oil viscosity is low (ISO 68 and below)
The most important thing to understand is that: bleeding does not mean that the grease is not suitable for use.
What to do when bleeding is spotted
Any base lying on top of the grease can be removed by decanting the free oil from the surface or manually mixing it with the rest of the grease.
The amount of oil that can be separated from the grease is generally negligible and represents a mere fraction of the total amount of base oil found in the matrix of the thickener system. Therefore, this small amount of oil will not adversely affect the consistency of the remaining product and will have little or no effect on the performance of the product.
Storage conditions
Due to the tendency of greases to bleed and release their base oils during storage, the best practice is to store the grease in a cool, dry indoor area that does not exceed 30ºC and remains above 0ºC. It must be taken into consideration that the proportion of oil released from greases increases over time and varies depending on the temperature at which it is stored.
Finally, it’s important that a drum or any other container of grease should never be exposed to direct sunlight or stored in an area directly near a heat source. This will only aggravate the bleeding rate. New grease cartridges should be stored vertically with the plastic cap up in order to help to prevent oil from leaking out of the tube.