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    Re: Sextants and Glue [was Sisteco Prismatic Compass]
    From: Fred Hebard
    Date: 2004 Mar 21, 17:38 -0500

    I used cyanoacrylic glue (Super Glue) to refit the filters.  Acetone
    cleaned off my slight excess of cyanoacrylic quite rapidly.  I didn't
    find any Un -Cure at the shops I went to, but I wouldn't be surprised
    if it's not acetone, or a similar intermediately polar solvent.  It
    looks like there aren't any antireflective coatings on the filters,
    which I wouldn't expect due to the harsh service (exposure to salt
    water) expected of a sextant.
    I also repaired the broken clamp in the case, which was what led to the
    filters being in such sad shape.  However, before the sextant is fit
    for sea, I would need to replace the clamp.  I believe I'll follow
    Jared Sherman's suggestion on this and contact Robert E. White & Co. in
    Boston, MA for the clamp.  They also sell reconditioned sextants; I
    wonder whether they still calibrate sextants.
    The Cassens & Plath is doing at least as well as my Husun; a few star
    shots the other evening came in at less than 0.35' of my actual
    location, and I still have not gotten really fine weather for
    observations, so I have hopes that it is not irretrievably foobarred.
    Then to buy a 6x30 scope!
    On Mar 20, 2004, at 12:17 PM, Fred Hebard wrote:
    > Thanks Joel
    > On Mar 20, 2004, at 11:53 AM, Joel Jacobs wrote:
    >> Hi Fred,
    >> I suggest you get some Cyanoacrylate clue. It come is various
    >> viscosities.
    >> The one I like is blue labeled Super Thin with a cure rate of 1-3 sec.
    >> Experiment with this on some test items until you feel comfortable
    >> with its
    >> running action.
    >> A companion product is Un -Cure, a debonder.
    >> The glue is space age technology, and will work with anything.
    >> Best Source: Your local hobby shop.
    >> I also have some spare parts that might work though they are
    >> Japanese, not
    >> C-P.
    >> Joel Jacobs
    >> ----- Original Message -----
    >> From: "Fred Hebard" 
    >> To: 
    >> Sent: Saturday, March 20, 2004 8:56 AM
    >> Subject: Re: Sextants and Glue [was Sisteco Prismatic Compass]
    >>> Jared,
    >>> I believe my sextant is the C&P Professional Sextant, as referred to
    >>> on
    >>> their website.  However, I am not familiar with older designs.
    >>> It has 3 horizon and 4 index filters plus an astigmatizer added to
    >>> the
    >>> the index filter rack.  There is no added button on the micrometer
    >>> dial
    >>> for adjusting for dip and index error.  The mirror housings are
    >>> aluminum, as best as I can tell.
    >>> Most lens systems I have disassembled glued the compound lenses
    >>> together, but mounted them with threaded rings in the barrel.
    >>> Retaining clips also could be used for filters.
    >>> If it's so easy to replace, do you know how I might dissolve the old
    >>> glue clinging to the two horizon filters that have fallen out and
    >>> what
    >>> sort of glue I should use to replace them?
    >>> Fred
    >>> On Mar 19, 2004, at 8:02 PM, Jared Sherman wrote:
    >>>> Fred, I would bear in mind that most of the finest camera lenses in
    >>>> the
    >>>> world today are in fact built up from multiple elements--glued
    >>>> together.
    >>>> Glue is literally the stuff that makes precision optics possible
    >>>> today.
    >>>> If the alignment and material selection is done properly, the glue
    >>>> joint is
    >>>> stronger, lighter, and thinner than screwed metal rings. It will
    >>>> never
    >>>> seize
    >>>> up, and it is easily replaced when and if need be.
    >>>> There are also combat aircraft whose wings are literally glued on.
    >>>> Glue is
    >>>> not necessarily a bad thing! And if it happens to keep down the cost
    >>>> of the
    >>>> sextant, even better.
    >>>> Which sextant did you get? How big is the filter rack on it? (How
    >>>> many
    >>>> filters?)

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