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Dear Henry.

1. Mercury seems to be available on the Internet.
Just type "mercury" on Google and you will find several
dealers which sell it. For about $100 per pound.

2. I have instructions, how to re-silver mirrors
from some old Navigation
book (about 1909) but this was not Bowdich.

3. I just thought you can share some personal experience,
it is always better than an instruction in a book.

4. I suppose that ordinary commercial glass
and household mirrors are not appropriate.
The glass for sextant mirrors has to be very flat and its
surfaces very parallel.
That's why I am talking about re-silvering existing
mirrors rather than making new ones.
I mean using glass from old sextant mirrors.

Alex

On Tue, 7 Nov 2006, Henry C. Halboth wrote:

>
>
> Hi Alex,
>
> I have, in the past, successfully re silvered mirrors in accordance with
> the directions in the 1909 Edition of Bowditch which do require the use
> of Hg. The later editions of this publication do not contain these
> directions, but I feel sure that some of the other earlier ones must
> include them. Until recently, I had some Hg in stock but frankly do not
> know where to buy it commercially these days; perhaps the lab at Perdue
> could supply you. At one time all the nautical instrument houses were
> able to handle mirror re silvering, the last I know of being New York
> Nautical Instrument, on Hudson Street in NYC. I recently spoke with the
> proprietor of a glass shop that also supplies mirrors commercially, who
> offered to cut mirrors for me to any size desired, but that, of course,
> did not include the split mirror generally employed as a horizon glass in
> the average instrument, but cannot speak to the optical quality of
> commercially made general purpose mirrors or their suitability for use in
> our instruments - this later might be a subject for ongoing discussion,
> as I would like to explore the use of mirrors as an alternative to Hg or
> oil as an artificial horizon reflecting surface. If you do not have
> access to a pub containing Hg re silvering instructions, I will be
> pleased to post them, as they are not lengthy.
>
> Regards,
>
> Henry
>
> On Mon, 6 Nov 2006 21:05:58 -0500 (EST) Alexandre E Eremenko
>  writes:
> >
> >
> > Dear Henry,
> >
> > On Mon, 6 Nov 2006, Henry C. Halboth wrote:
> >
> > > As long as there is no deformation, I believe restoraton to a
> > condition
> > > of serviceability is entirely possible. I have done so with
> > several old
> > > sextants/octants that have been missing a variety of parts
> >
> > Do you make/resilver mirrors yourself?
> >
> > I am currently shopping for an old vernier sextant,
> > mostly paying attention on the state of the arc,
> > frame, vernier and filters.
> >
> > The requirement that mirrors should be also in good condition
> > substantially narrows my choice. So I thought of trying to
> > learn how to resilver mirrors myself.
> > Can you give any advise on this?
> >
> > I have in mind a recipe from an old navigation book
> > which requires mercury and tin foil.
> >
> > Alex.
> >
> >
> > >
> >
>
>
> >


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