Grease Selection Made Simple

First question- what is grease?

Grease is simply a semi-fluid product that’s made up of an oil (70-90%) combined with a “thickener” (5-15%). Added to the mix are a few special additives (3-10%) to make some specific improvements and you have GREASE!

 Now we get a little more technical

1. There are two main types of grease –
   1. ‘Metal Soap’ Thickener grease (Aluminum, Barium, Lithium, Sodium, Calcium, etc.)
   2. ‘Non-Soap Thickener grease (Polyurea, Clay, Silica)
2. Grease is named after its thickener type –
   1. Example – Aluminum Complex, Lithium Complex, Polyurea and many others are classified and known by their thickener type
3. More info about 2 of the most popular grease types –
   1. Lithium Complex Grease
      • General purpose
      • Good anti-wear and extreme pressure properties
      • Good water resistance
      • Good heat resistance
      • Good in low temperature applications
      • Good for roller and spherical bearings
      • Accounts for more than 50% of all grease usage

2. Polyurea Grease
   • Used mainly in ball bearing applications – electric motors
   • Excellent low temperature pump-ability
   • Water resistance is satisfactory to excellent
   • Excellent heat resistance
   • Not good in slow-moving applications
   • Polyurea does not work well in roller and spherical bearings

4. If a compromise is a must for motor bearings, use Lithium Complex

    

5. Grease can be a very complex subject but 99% of the typical applications found in the industry can be satisfied with a minimum number of greases such as those above. However, special applications may require further investigation for the proper grease.
6. A few tips  –
   1. Do not mix grease types! Compatibility is an issue with many grease types.
   2. Use the same grease in a bearing for the life of the bearing.
   3. Send a tube of the grease you are using in your motors with the motor when it goes off to the repair shop.
   4. Use button-head grease fittings on your motors instead of regular zerts