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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!

Fred

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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