Degradation 6 – Varnish

Degradation 6 – Varnish is a foundational course that explains how lubricant degradation leads to the formation of varnish, one of the most persistent and damaging issues in fluid power and rotating equipment. Varnish deposits can cause valve sticking, flow restriction, overheating, and ultimately unplanned downtime.

In this course, you’ll follow the complete varnish formation cycle—beginning with oxidation and progressing through polymerisation, solubility changes, precipitation, and agglomeration. You’ll also explore the various accelerators that drive varnish formation and how these processes interact with system conditions and lubricant chemistry. Finally, the course covers the real-world impacts of varnish on equipment performance, control stability, and maintenance costs.

Whether you’re in power generation, refining, or heavy industry, this course will give you the insight to identify early signs of degradation, communicate the risk of varnish to stakeholders, and take proactive steps to prevent failure.

Key learning outcomes include:

• Understanding the chemical and physical processes that lead to varnish formation
• Recognising the stages of varnish development in oil systems
• Linking symptoms in the field to root causes in oil chemistry
• Identifying environmental and mechanical factors that accelerate varnish
• Supporting data-driven maintenance decisions and condition monitoring strategies