NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Bill Morris
Date: 2023 Feb 27, 15:48 -0800
David, I think your surmise about the three recording rings of your Plastimo sextant must be correct. If they are stiff to turn, lubricate with silicone grease.
If you unscrew the black plug in the base of the handle, a sort of torch will come out. If you then unscrew the black plug from the torch thing you will get access to the battery, via a small spring which is loose and easily lost if you don't know it is there. One end fits in a groove in the plug and the other end sits against the base of the battery. On the handle should be a round sticker saying, in French "lighting press here". If your sticker has been lost at sea, press around with your thumb and you will find a soft spot half way up the handle.
To refill, you will find _two_ tiny Allen grub screws between the top and middle rings. Unscrew them with a 1.5 across-flats Allen wrench untill the head is flush with the outside of the casing, when you will find that it is possible to wringgle out the capsule. This will reveal a filling screw and a temperature compensation diaphragm. I do not recall what the filling fluid is. I would suggest thin silicone oil or something else that does not attack the plastic. Alcohol would probable do too. Perhaps Monsieur Plastimo could tell you. In any case, use a bit of plumbers tape around the filling screw.
The fixing screw tips fit into holes in reinforced areas of the capsule. Take care to align these areas with the screws, which you do not need to tighten up hard, but only enough to secure the capsule in the handle. Too hard and you may hear "un craque! Merde!"
If anyone in New Zealand would like a Plastimo hand bearing compass for the price of a cheap bottle of wine plus postage, the first to e-mail me gets it
Bill Morris
Pukenui
New Zealand
nzengineernz@gmail.com