Bright stock, a high-viscosity Group I base oil, has been prevalent in the lubricant industry for decades in industrial applications. When production has been plentiful, bright stock has been used as the base oil for everything from industrial gear oils to greases. Essentially, it is a breadbasket component that encompasses multiple end uses and has the following benefits for grease manufacturers:
- Thickening properties that enable formulation in higher-viscosity ranges
- Compatibility with other oils, additive packages and viscosity modifiers
- Historically proven performance, which allows blenders and end users to be more comfortable with its use in finished lubricants
- Ability to be used as a high percentage of the finished lubricant formulation
Although these advantages are important, developments in recent decades have revealed that bright stock also brings with it some potential pitfalls.