Grease Selection Made Simple

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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
    1. 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
  1. If a compromise is a must for motor bearings, use Lithium Complex

  2. 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.
  3. 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

Terry Taylor

Terry Taylor

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