iHenning. Kerosene, Naptha, Lamp Oil, Compass Fluid… anything like that, close to the viscosity of water. You can also use high proof alcohol which is what they used to use until the sailors started drinking it because the US Navy had dry ships. That’s why they’re also known a s “Whiskey Compasses”.

mineral spirits
The fluid is mineral spirits. There should be a fill / drain hole on the compass.

Modern compasses usually use a magnetized needle or dial inside a capsule completely filled with a liquid (lamp oil, mineral oil, white spirits, purified kerosene, or ethyl alcohol are common).

Locate the filling screw on the side of the compass. Position the compass so that the filling screw is facing upward. Remove the filling screw by turning it counterclockwise with a screwdriver. Jostle the compass gently to bring any trapped air bubbles to the fill hole.

Compass Fluid contains alcohol concentration. It is important to note that this compass fluid may not be compatible with some compasses, user should decide on the usability of this product. DANGER: Harmful or Fatal if swallowed; Combustible. Keep from heat, sparks, open flame, or other ignition sources.

If you ever need to refill or top off the fluid in your Ritchie compass, the manufacturer recommends Isopar L, an odorless, colorless, refined synthetic fluid. Its low viscosity promotes quick swinging.

COMPASS FLUID. Many types of fluid have been used over the years to fill liquid-damped compasses. The presence of fluid acts to damp the horizontal circular oscillation of a compass card and allows the card to settle on north much faster than air-damped compasses.

This compass liquid may be used in CASSENS & PLATH compasses. This liquid contains isopropyl alcohol.

Usually, the bubble will disappear when the compass is returned to sea level and/or room temperature. If it doesn’t, place it in a warm spot-like a sunny windowsill-so the liquid can heat, expand, and return to it’s normal volume.

It is not alcohol, it is mineral oil. You will probably get a lot of good (and not so good) suggestions, but one readily available source for mineral oil is Baby Oil, like Johnson and Johnson. It is pure, clear mineral oil and does work.

The compass is considered an instrument. FAR 1.1 under maintenance explains calibrations are considered a repair. So this just leaves repair stations to adjust/swing your compass. Needless to say a pilot cannot perform this task as it is not considered preventive maintenance.

It is important to note that this compass fluid may not be compatible with some compasses, especially compasses that were originally alcohol-filled. The very early fluid-filled compasses made from around 1860 were filled with an alcohol and water mixture. Compass oil was not commonly used until the 1940’s.

It is designed for Ritchie compasses but is compatible with most oil filled compasses. It is important to note that this compass fluid may not be compatible with some compasses, especially compasses that were originally alcohol-filled.

Compass oil was not commonly used until the 1940’s. If there is any question about what type of compass fluid is needed please contact our repair department.