Mixing different types of greases

When you start to use a new grease in an application, it is important to know whether the new and the old grease are compatible. This depends on whether the thickener and/or the base oil can mix with each other. A number of things can happen when two different greases are mixed:
- Nothing, i.e. the two greases are miscible
- The grease mix hardens, which can be devastating in, say, a central lubrication system
- The grease mix softens. The soap structure is broken down and the greases are not miscible. This can cause leakage and bearing failure
- We can help with miscibility tests ahead of product changes to avoid problems in advance. Feel free to contact us if you need help.
Thickeners - miscibility
Thickener | Li | LiX | Ca | CaH | CaX | CaSX | Clay | ALX | BaX | PU | Na | NW |
Lithium (Li) | + | o | + | - | + | o | - | o | o | - | + | |
Lithium complex (LiX) | + | + | + | + | + | - | + | o | - | o | + | |
Water-stabilised calcium (Ca) | o | + | + | - | + | o | - | o | o | o | + | |
Water-free calcium (CaH) | + | + | + | o | o | + | + | o | - | - | + | |
Calcium complex (CaX) | - | + | - | o | + | o | o | - | + | o | + | |
Calcium sulfonate complex (CaSX) | + | + | + | o | + | - | - | o | + | - | + | |
Clay | o | - | o | + | o | - | - | o | o | o | + | |
Aluminium complex (ALX) | - | + | - | + | o | - | - | + | o | - | + | |
Barium complex (BaX) | o | o | o | o | - | o | o | + | o | + | + | |
Polyurea (PU) | o | - | o | - | o | + | o | o | o | o | + | |
Sodium (Na) | - | o | o | - | o | - | o | - | + | o | + | |
NOVA Technology (NW) | + | + | + | + | + | + | + | + | + | + | + |
+ = Compatible | o = Miscibility test required | - = Not compatible
The above table is based on the type of thickeners only. Please note that different types of additive may affect miscibility.
More about grease

Handbook
The Law of Least Resistance - The FUCHS Lubricants book regarding greases.