NavList:

John Fosh you wrote: I am trying to find someone who can repair or replace my KH Mate horizon mirror. The reflection half obviously suffered from moisture some years ago. I originally bought the instrument when it was new about 1952.  shall be grateful for help. Thank you.

A lot depends upon where you live, how seriously you want to use your sextant, and how much you want to spend.  I just rang B Cooke & Son Ltd, 58-59 Market Place, HULL, East Yorkshire, United Kingdom, HU1 1RH. 0044 (0)1482 223 454 , bcs@cooke.karoo.co.uk .  https://bcookeandson.co.uk/ .  They will resilver your horizon mirror for you, but it will cost around £60GBP.  You can send just the mirror, the mirror in its surround, or the complete sextant.  They suggested that if you were going to use it seriously, they could recollimate the whole sextant and return it with a certificate.

You could of course try to resilver said mirror yourself.  Instructions are available online, but I’ve never tried it.  If you’re a ‘just for fun’ navigator these days, you might try buying  a vanity mirror or mirror tile of the correct thickness; cutting it to the correct size; masking off the mirror half, and removing the mirroring on the clear bit.  You can do this with paint stripper to remove the protective paint, then ferric chloride to remove the mirroring.  I did this on the plywood sextant I made, and it’s perfectly OK for fun work.  I’m also including a photo of the back of an old Hughes index mirror, which came as a spare with my Mate’s Three Circle sextant. It’s fractionally larger than the horizon mirror and 3.8mm thick. The lay-up appears to be:  glass, mirroring, thick paint, and a thin metal film (possibly lead).  DaveP

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