Valve oil

Valve oil is a lubricant for valves of brass instruments. It is typically comprised mostly of mineral oil with a small amount of other ingredients.

Use of valve oil

Besides lubricating the moving parts of the valve, valve oil provides corrosion protection to the bare metal of the inner valve. While the valve piston or rotor is made of a metal which is more resistant to corrosion, the inner valve casing is typically bare brass. (The brass on the outside of a modern instrument is lacquered to prevent corrosion.) The oil also completes the seal between the valve casing and the piston or rotor.

Although a clean and unoiled valve of a well maintained instrument should move without unusual force, the inside of a musical instrument is a very inhospitable environment for a delicate valve mechanism. The musician constantly blows warm moist air through the valve. To make matters worse, impurities may be blown from the musician's mouth into the instrument. Even if nothing grows in the valve, the condensation and changing temperature of the metal can cause an untreated valve to bind, possibly resulting in a stuck valve. Even a minor binding of a valve affects the playability of the instrument and is at least very annoying. Also, woodwind musicians use valve oil (called key oil for woodwinds since they do not have valves, they have keys) to lubricate the mechanism of the keys to improve the springback action. However, woodwinds usually oil their keys only every few months, whereas some brass players lubricate their valves several times a week.

Types of valve oil

There are two main types of valve present on brass instruments: piston and rotor. Accordingly, vendors sell different types of oil, including scented varieties. Some vendors recommend up to three different types of oil for some valve types. Slide oil for trombones is also a very similar solution. The difference between the types of oil is primarily the viscosity. The minerals in the valve oil are dangerous and can cause serious health problems if swallowed.

While many brass players may claim one particular brand of valve oil to be better than others, it should be noted that valve oil is no more than a petroleum distillate, with properties very similar to kerosene.