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Tinsley Saturn Help with Delamination

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#1 jragsdale

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Posted 11 September 2021 - 11:59 AM

Hello, I recently acquired an old Tinsley Saturn pull out spotter and the cemented doublet objective seems to be delaminating on the edges. There's a definite edge that shows a lot of color at angles. I tried to take a picture the best I could. What is recommended for this? Would complete removal of the cement and re-gluing with basalm be needed? Or would some optical immersion oil suffice for a mostly fix? Thanks! -Jordan

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#2 ngc7319_20

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Posted 11 September 2021 - 12:32 PM

The lens is probably useable "as is" unless the delaminated area has turned cloudy.  

 

Yes it could be separated and repaired.  I have used 91% rubbing alcohol or acetone and soaked it until it comes apart -- sometimes takes days.  Some people use heat in an oven which is much faster.  Once it is apart, clean up the remaining cement. I would suggest to use immersion oil or mineral oil for a temporary re-space.  I think this is best, because it is easily repeated if there are problems.  You must be careful not to introduce wedge or tilt in between the glasses, and avoid any de-center.  If you just use oil and re-assemble in the cell, you should be fine.

 

Optical cements (like Norland UV cure) are easy to use, and can be cured under a fluorescent lamp. But will be very hard to fix if something goes wrong.

 

https://www.edmundop...dhesives/11818/


Edited by ngc7319_20, 11 September 2021 - 12:33 PM.


#3 Kasmos

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Posted 11 September 2021 - 01:47 PM

If it continues to bother you and you want to repair it without oil or glues you could try this:

 

https://www.cloudyni...0mm/?p=10020264

 

Another CNer once mentioned doing it and it was the first time I've done it.

Some might say the spacing is not exactly the same and the color correction might be affected.

That said, the magnification that small scopes are used at makes many issues less critical plus this fix is reversible. 

BTW, I just used the finder in the link last night and it worked excellent. Jupiters Moons were easily visible.



#4 DAVIDG

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Posted 11 September 2021 - 07:38 PM

 I have recemented many many lens. Here is a  link to my thread on how it is done. 

 

           https://www.cloudyni...ecement-a-lens/

 

                      - Dave 


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#5 RichA

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Posted 12 September 2021 - 05:20 PM

Hello, I recently acquired an old Tinsley Saturn pull out spotter and the cemented doublet objective seems to be delaminating on the edges. There's a definite edge that shows a lot of color at angles. I tried to take a picture the best I could. What is recommended for this? Would complete removal of the cement and re-gluing with basalm be needed? Or would some optical immersion oil suffice for a mostly fix? Thanks! -Jordan

Could always remove it, soak it in acetone for a couple days to see if the cement dissolves than airspace it when you put it back.  High viscosity silicone oil (like AP uses) is available on Amazon if you want to try it.


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