Reversibility
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Kestas
Staff member
I believe that's where the oil component of the grease separates during use, then gets resorbed later.
more like shear stability when a grease is "worked" it will thin upon standing it will thicken back up, some are better than others.
Reversibility is not the right term but I forgot which term is correct tho.
bruce
Reversibility is not the right term but I forgot which term is correct tho.
bruce
Kestas
Staff member
Quote from the first link:
Then it goes on to cite examples of how more thickener gives it more reversibility. I think this writing should be edited. It's either wrong or confusing.
The page http://www.bobistheoilguy.com/GREASE/index.htm looks more like PROPERTIES of GREASES than FUNCTIONS OF A GREASE.
just like Kestas said,
where the oil component of the grease separates during use, then gets resorbed later
where the oil component of the grease separates during use, then gets resorbed later
I do not believe this is a ASTM test is it? or is it a schaeffer oil test.
bruce
bruce
I was kind of curious as to what test method they used also so I submitted the question to NLGI. It's not just a Schaeffer's test as I have seen this mentioned on techical papers and data sheet's but never how they performed the test. when I get an answer from them I'll post it.
Kestas
Staff member
D-6184 is a oil bleed test not the "reversibility"
test discussed here, there are 2 or 3 oil seperation tests.
I do not know of one ASTM test that reports how a grease "sucks" up the seperated oil at a future date. If ASTM not just a in house test I would like to know ASTM #.
Thanks
bruce
test discussed here, there are 2 or 3 oil seperation tests.
I do not know of one ASTM test that reports how a grease "sucks" up the seperated oil at a future date. If ASTM not just a in house test I would like to know ASTM #.
Thanks
bruce
I'm still hoping to get a reply from the NLGI but found some info on a Whitmore's data sheet for one of their greases. here's an exerpt.
"Good reversibility properties can be defined as the ability of the grease to maintain (or revert to) its normal consistency (NLGI grade) after it
has been heated and cooled repeatedly. Many applications involve intermittent temperatures within a bearing that will approach or perhaps even exceed the dropping point of a grease and periodically return to ambient temperature."
It looks like they are using ASTM D-217 cone penetration test as a way to verify reversibilty
[ January 22, 2006, 11:33 PM: Message edited by: RB Shannon ]
"Good reversibility properties can be defined as the ability of the grease to maintain (or revert to) its normal consistency (NLGI grade) after it
has been heated and cooled repeatedly. Many applications involve intermittent temperatures within a bearing that will approach or perhaps even exceed the dropping point of a grease and periodically return to ambient temperature."
It looks like they are using ASTM D-217 cone penetration test as a way to verify reversibilty
[ January 22, 2006, 11:33 PM: Message edited by: RB Shannon ]
That is what I was refering to I still Do not think a oil reversibility re absorbing test is a real ASTM but is just a "schafer" test.
bruce
bruce
RB Shannon said it correctly,and as being a Schaeffers test,Bob is putting it simply but accurate,,Aluminum Complex thickener can and has a excepional relation to the bases for more extreme say coming back after a workout lubricating a surface in more adverse conditions as time,moisture,heat,cold,vibration,impact,etc over some other thickers and bases,providing its properly blended and cooled after compounded at the time of being produced,,,,,,,,,BL
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