Effects of silicone vapor on brush wear

The lubrication of graphite by water vapor is now well known. Many other condensible vapors, however, have been found equally effective. Demonstrations occurred during the high-altitude testing of aircraft brushes during the war. It was found that certain solvents from the freshly painted interiors of cold chambers provided vapor lubrication for brushes operating under dry conditions, and brush dusting which normally would have occurred was prevented. The easily condensible vapors as a class, excepting corrosive substances, thus gradually became recognized as lubricants for carbon brushes.