Builders' Forum Archives
Re: Liquid Compass Questi
Posted by Terry Mcadams on Nov 23, 2004
Yeah, Cliff is right. Mineral oils can get pretty cold before freezing, but the "pour point" of the oil is more critical than the freezing point for compass performance in cold weather, i.e., the point at which the oil ceases to flow under specified conditions. This can vary among the natural mineral oils, depending on the amount of wax in them. It's the wax that crytalizes and impedes flow. My guess is that the compass manufacturers use synthetic, wax-free oils that can get REALLY cold and still pour. I have an old hand compass that I've had as cold as 30 below zero F on Mount Washington and it still worked. I didn't work very well, but the compass did.
In Response to: Re: Liquid Compass Questi by Cliff Herring on Nov 23, 2004