BASIC GREASE FUNDAMENTALS
Grease is used by almost every customer that we visit with. Around 90% of rolling element bearings are lubricated with grease along with a ton of other applications such as bushings, pins, open gears. It’s a vital part of any maintenance program and often one of the most overlooked lubricants in the facility. We hear the typical, “I need a high temp grease” or “I need #2 Grease”. And the fan favorite of, “I need RED high temp grease”. These are all typical from customers that do not understand that two identical greases that can have similar performance and will work in their application but might have a different color. One being RED and the other being GREEN.
It is our job to inform and educate the customer through our own knowledge that their “high temp” doesn’t always equal someone else’s “high temp”. And that just because the grease is RED, does not mean that its high temp.
Here are some basic grease fundamentals, so your next conversation with your customer goes smooth.
1. Grease is formulated by blending BASE OIL, THICKENER and ADDITIVES.
2. Base oil typically builds the film thickness, separating the roller from the race.
3. Thickeners hold the base oil and additives together like a sponge. There are some thickeners that provide additional performance characteristics, Calcium Sulfonates for example, that provide AW and EP type protect. Thickeners come in several different types and each provide a slightly different property to the finished grease.
4. Additives are blended in to provide 3 main functions. Enhance, Suppress or Impart new properties to the base oil. Anti-Wear (AW) additives supply protecting to metal surfaces by forming protective films during start up conditions. Additives such as Moly and Graphite are often suspended in the grease to reduce friction and wear to metal surfaces during heavy loading and slow speeds.
5. NLGI Consistency – The NLGI uses a scale from 000 (Semifluid) to 6 (Firm Block). This rating is all based on a work penetration number. A #2 grease will have to be between 265-295 on the scale to be considered a #2.
6. Keep It Clean – Unlike oil, grease cannot be filtered. Anything that gets into the grease, via the tip of a grease gun, open keg or barrel or when packing bearings will be introduced into the application. Keeping containers tightly closed and wiping off the tip of the grease gun will aid in reducing ingress of external contamination.
7. Don’t Mix Greases – Many types of greases are incompatible. Grease A maybe a Lithium Complex multipurpose grease while Grease B has a Aluminum Complex thickener and is also considered a multipurpose grease. Compatibility goes back to the type of grease currently used, new grease, how much purge can happen, temperature of the application and intervals between greasing.
8. #2 Doesn’t Always Mean #2 – Since NLGI Consistency is a measurement of how soft or hard the grease is, manufactures will use different ratios of Thickener and Base oil to get the consistency needed. For reference, Grease A may use a base oil of ISO 68 and use additional thickener to get the consistency of a #2 grease. Grease B may use a heavy ISO 460 Base oil and use smaller amounts of thickener to get the same #2 consistency.
9. No Color Code – Grease colors have no standardized meaning. Red does not signify high temp and blue does not mean electric motor grease.
10. Proper grease selection comes down to the application. Just because the customer currently uses a Lithium Complex in their application does not mean it is the best possible grease or even the right grease.
Often after review and understanding the customer’s needs, we can make efforts in consolidating greases or recommending greases that provide better protection and in the long run saves the customer money by reducing maintenance costs.
You can check out our grease products here.