Grease Compatibility

Dear Graeme Vivian,
I have information that these two types of thickeners are compatible or nearly always compatible.
If a mix of these greases in case of incompatibility become thin the product will flow out from the bearing simply (as result - oil starvation).
If in case of incompatibility the mix will become thick, bearing will be more difficult to run and it will be generate the heat more strongly in comparison with work under normal conditions. Additional heat either will fuse a mix and it will leak from the bearing (oil starvation) or will transform mix of greases into compound that similar plasticine and which will be saved in all "dead" zones of the bearing and will not act in details lubrication (again oil starvation).
I think, that consequences are clear.

If you wanted to do a compatability study in house you can take a 50-50 mixture of the two greases and mix them well in a container and then allow them to sit for three days and then re-examine them for a texture change. Let me know what you find. If you want to accellerate the test allow the mixture to sit for in an oven for four hours at 160 degreed F. This is a quick in house technique to use that will give pretty reliable results without going through lab ($$) testing,

incompatability of greases can be indicated by change in consistency, mechanical stability, and thermal resistance. It is not just the thickener type which should be looked at. The grease is a combination of the thickener, additives and base oil and any of these can react with the other components of the other grease.
In general, mixing greases should be avoided by thorough cleaning or flushing of equipment at changeover. If mixing cannot be avoided then a compatibility test should be carried out to confirm there are no problems, even with thickener types that are considered to be compatible.