A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Bob Peterson
Date: 2023 Mar 13, 11:21 -0700
Okay, I'm going to weigh in. My exerience with Plastimo compasses has shown issues with pivot and jewels going bad, and the P/J are the heart of any compass. I've seen some (in general) where the pivot looks like a nail smashed by a hammer under a microscope. Then the card/dial will not swing freely; free rotation is vital. So, test all compasses this way:
-- on a wooden table, let the card settle for length of time.
-- note the heading number.
-- bring small magnet up to the card and pull off the heading by no more than 5 degs, small amount.
-- remove the magnet. the card should return to the original number exactly. failure says the P/J is shot and needs to be replaced.
And the P/J cannot be replaced on any Plastimo compasses. They are sealed capsules. And beware the fluid. It can get nasty. The green color usually comes from sulfur leaching out of the gaskets.
If you chose to refill, the fluid needs to be evacuated of gas in a vacuum chamber. Good luck.
-- Robert S. Peterson Great Lakes Compass 31 N Alfred, Elgin IL 60123 USA 847/697-6491 Compass expertise for Lake Michigan navigators since 1985 email: glcompass(at)astound(dot)net web: https://www.greatlakescompass.com/