NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: on washing sextants
From: Courtney Thomas
Date: 2004 Aug 3, 09:52 -0500
From: Courtney Thomas
Date: 2004 Aug 3, 09:52 -0500
Joel, I have a SNO-T with the barrel enclosed tangent screw. How do I properly gain access to the tangent screw ? Also, what should be done to preserve rubber eye cup pliability ? Appreciatively, Courtney Joel Jacobs wrote: > Peter, > > The most damage that befalls a sextant is due to living in a salt > atmosphere, particularly when used from small craft where they are subject > to frequent spray. Salt water, left unattended will first attack the > mirrors. The backside of the mirror's frames have a trough which collects > more of this spray then elsewhere and this starts to erode the silvering. In > time, it also will eat into any chrome parts, cause the paint to bubble and > lift on the frame. It will do major damage to a sextant with an aluminium > frame as salt water is a strong electrolyte. > > The prevention is to rinse the sextant in fresh water after each use, > whether its been subjected to salt spray or not. If the sextant has its > tangent screw encased in a barrel or cylinder like the Russian and > Freiberger sextants make sure to run a lot of water through it which will > keep the screw from freezing. Then of course wipe down with a soft cloth. >>From time to time, you may also add some lubricating oil to the tangent > screw for protection on those that are housed. This is not necessary on > sextants with open screws. Doug Royer recommends NYOIL. Jared Sherman > recommends DuPont Krytox. I use what I have handy which is Vaseline and > Never Seize. The latter only on a tangent screw encased inside a barrel or > cylinder because it does stain. > > Doug some time ago wrote a message which went into great detail of how he > and others on his ship took great pains to clean their instruments and > protect them. One of his recommendations was the use of RainX on the > mirrors. Hopefully he saved that message and can re-send. > > I also would like to hear what Jim Thompson has to say. He has one of the > most comprehensive sites on the internet devoted to CELNAV. > > Joel Jacobs > > > > ----- Original Message ----- > From: "Peter Fogg"> To: > Sent: Monday, August 02, 2004 10:45 PM > Subject: on washing sextants > > > >>Quoting Joel Jacobs >>..where I >> >>>was talking about washing a sextant after use. >>> >>Would Joel, or anyone else, like to go into a little detail about this >> > sextant washing idea? > > -- s/v Mutiny Rhodes Bounty II lying Oriental, NC WDB5619