Grease compatibility chart and info

dnewton3

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All - This is being posted as a sticky for reference. Often questions arise about greases which can be easily answered in this article. One of the most important things to realize is that there are a lot of greases which are not compatible with others. Whereas many oils which meet API specs can be safely mixed within their category (SN, GL-5, etc), that same context does not always exist with grease. Performance specs for grease do not assure compatibility; greases which meet the same performance standard can have vastly different make-up and not work well together. And to further add concern, some grease compatibility charts actually contradict other charts! https://www.machinerylubrication.com/Read/30727/determine-grease-compatibility " Several contradictions were discovered among the various charts. ... Although there were significant disagreements between the various charts, they all had one thing in common - few provided any link or reference to research that was conducted to develop them. That is to say, the charts being used to make significant engineering and design decisions are contradictory and do not indicate the source of information or research used to compile them." https://www.machinerylubrication.com/Read/1865/grease-compatibility "To add to the confusion, there are some grease specifications that are based solely on grease performance without regard to grease composition. If greases of different thickener types (both of which meet the performance requirements of the specification) get mixed in service, dire consequences can result." If i understand correctly; for example your axle calling for GC/LB (refers to applications) and NLGI#2 (refers to thickness), it does not mean that all greases meeting those specs are compatible. If you are unsure of what grease currently exists in your application, you have two choices: 1) completely purge the application and use a grease you choose which will have the correct performance criteria for that application 2) contact the maker of the component and ask if they can give you the specific brand name and product number of what was installed OEM, assuming it has not been altered by someone else prior to your ownership In low-load/low-speed applications, this may not matter much (ex: hinge pins, low-frequency sliding contact, etc). In high-load/high-speed applications it matters quite a bit (ex: wheel bearings, pulley bearings, loaded shaft bearings, high-pressure contact surfaces, etc).
 
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Thank you for posting this. Both links show the difficulty of determining the compatibility of polyurea grease, which is why I decided not to use it for general equipment greasing years ago.
 
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Very interesting, I have also noticed in the past that 'some grease compatibility charts actually contradict other charts! ' Each major manufacturer has its one compatibility chart. Not to take into consideration the changes in formulation and technology as the years go by. So among the most reasonable actions would be indeed to purge the old lubricant completely and use the new product on a tabula rasa.
 
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Taking compatibility beyond the generic charts and the fact that they are inconsistent and are really not dependable, compatibility must include base fluid and additive compatibility. Compatibility must be tested. ASTM D6185 is a great method. It takes into account changes in consistency (thicker and base oil) as well loss of performance, specifically corrosion and load-carrying.
 
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is there a chart showing grease compatibility per application and effect on various types of rubber seal material?
 
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Most of the time it's the base fluid of a grease that will effect elastomers. If you know the BO type, Google compatibility of it with the elastomer type. If you don't know the elastomer type search for compatibility with any elastomer such as NBR. Hopefully this leads your to an elastomer manufacturer's compatibility table.
 
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im currently using REDLINE CV2 grease with a Calcium sulfate thickner and want to use Shell Rotella MP with a Lithium Hydroxstearate thickner would this cause an compatability issue?
 
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im currently using REDLINE CV2 grease with a Calcium sulfate thickner and want to use Shell Rotella MP with a Lithium Hydroxstearate thickner would this cause an compatability issue?
anyone have an answer or input to this
 
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Could you please format that so it is more readable? Tried two different browsers and is a mess on both. Thanks.
@Dave9 Who or what are you referring to? The original post on top, the comment before yours, or something else? I don't understand the bit about two different browsers – what is a "mess"? What would different browsers do?
 

X15

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@Dave9 Who or what are you referring to? The original post on top, the comment before yours, or something else? I don't understand the bit about two different browsers – what is a "mess"? What would different browsers do?

Pretty sure he was referring to the original post, it was written before they updated the forum software, and unfortunately they didn't reprocess the old posts to fix the formatting.

All -
This is being posted as a sticky for reference. Often questions arise about greases which can be easily answered in this article. One of the most important things to realize is that there are a lot of greases which are not compatible with others. Whereas many oils which meet API specs can be safely mixed within their category (SN, GL-5, etc), that same context does not always exist with grease. Performance specs for grease do not assure compatibility; greases which meet the same performance standard can have vastly different make-up and not work well together. And to further add concern, some grease compatibility charts actually contradict other charts!

"Several contradictions were discovered among the various charts. ... Although there were significant disagreements between the various charts, they all had one thing in common - few provided any link or reference to research that was conducted to develop them. That is to say, the charts being used to make significant engineering and design decisions are contradictory and do not indicate the source of information or research used to compile them."

"To add to the confusion, there are some grease specifications that are based solely on grease performance without regard to grease composition. If greases of different thickener types (both of which meet the performance requirements of the specification) get mixed in service, dire consequences can result."

If i understand correctly; for example your axle calling for GC/LB (refers to applications) and NLGI#2 (refers to thickness), it does not mean that all greases meeting those specs are compatible.

If you are unsure of what grease currently exists in your application, you have two choices:
1) completely purge the application and use a grease you choose which will have the correct performance criteria for that application
2) contact the maker of the component and ask if they can give you the specific brand name and product number of what was installed OEM, assuming it has not been altered by someone else prior to your ownership


In low-load/low-speed applications, this may not matter much (ex: hinge pins, low-frequency sliding contact, etc).
In high-load/high-speed applications it matters quite a bit (ex: wheel bearings, pulley bearings, loaded shaft bearings, high-pressure contact surfaces, etc).
 
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If a grease is not compatible with another, and they get mixed in a ujoint or suspension component, what happens?
It risks the thickener degrading and releasing the oil which then runs out, leaving inadequate lubrication or in some cases it can harden, also becoming inadequate so you have accelerated wear, and potentially undesirable noise. In rarer cases, the grease may not be compatible with the component you are lubing, particularly its rubbery bits.
 
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@Dave9 Who or what are you referring to? The original post on top, the comment before yours, or something else? I don't understand the bit about two different browsers – what is a "mess"? What would different browsers do?
Better question is why are you second guessing my post? You can't see the post which has no formatting?

Different browsers can render pages differently, including text formatting, something I'm often faced with during QA of site changes, that you have to test for different browsers/versions.
 
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Better question is why are you second guessing my post? You can't see the post which has no formatting?

Different browsers can render pages differently, including text formatting, something I'm often faced with during QA of site changes, that you have to test for different browsers/versions.
I still don't know what you're referring to. It you mean the single long paragraph in the original post, that won't be affected by browsers at all. A browser won't add paragraph breaks to text. But I'm not sure what you meant, since "mess" implied something that was broken or jibberish.
 
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^ A great wall of text without breaks is in fact considered a mess to many people, and yes browser compatibility can affect text formatting whether it be breaks reflowed in a different way or just spacing lost.

What does it matter if you understand since it wasn't your post that was the great wall of text? It's beside the point, after realizing that the problem was the reformatting from the forum SW change, and yet, the post could still be cleaned up...
 
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^ A great wall of text without breaks is in fact considered a mess to many people, and yes browser compatibility can affect text formatting whether it be breaks reflowed in a different way or just spacing lost.

What does it matter if you understand since it wasn't your post that was the great wall of text? It's beside the point, after realizing that the problem was the reformatting from the forum SW change, and yet, the post could still be cleaned up...
I mostly hoped you'd communicate to whomever you were trying to communicate with, since you left everything so unclear, even who you were talking to. There was no way for anyone to do anything, and the browser bit was extremely confusing. No browser will render a huge paragraph any differently from any other browser – the poster will have to edit it.
 
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