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Peter Lewis
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 15, 2005 - 09:51 pm: | 
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I just purchased a Spiratone 85mm f1.9 lens on e-bay (said to be in excellent condition...riiight! Anyway, it has the usual snowflake signs of lens element seperation. How do I finish what Nature has begun, and then clean off the old cement, so that I can re-cement the elements?
I've already learned that "purchased from estate", "selling for friend", "don't know much about these" etc. are all e-bay code for "the seller knows it's broken but doesn't want to admit it." |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 16, 2005 - 03:46 am: |
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If lens are cemented by genuine canada balsam, their separation is easy. Put lens pair into water and get warm water slowly. When water temperature is 80-90 degree Celsius, canada balsam get melt and lenses are separateable. Rest of balsam you can clean by (pure) alcohol. For re-cementing you will need a little of canada balsam or synthetic optic cement. Warning - if lens is very old (50 years or more) is better to sign location of elements each other. Old lenses were hand assembled and position (turning) of two lenses in pair is important, it can have influence to optical quality.
If elements are cemented by synthetic glue, it is problem. You can try to separate elements by xylen. You have to plunge lens pair into xylen for several hours. Attention, xylen is toxic! |
charlie
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 16, 2005 - 07:27 am: |
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Xylene used to be available in auto parts store as carburetor cleaner. |
paul ron
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 16, 2005 - 08:27 am: |
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There is an orange smelling stuff that replaced xylene used in histology labs. if you have a lab near you or know a tech, ask em for a little. You can also get a bit of balsam too that they use to mount specimens. |
Peter Lewis
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 16, 2005 - 07:17 pm: |
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Thanks. I'll try the hot water first, this is an old t-mount pre-set lens, so maybe I'll get lucky and it won't be synthetic. Or maybe, if I was really lucky, it would have been synthetic and never have seperated in the first place! |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 17, 2005 - 12:10 am: |
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Hello once again, there is a long text aboug cementing of lenses: http://www.atmsite.org/contrib/Sapp/LensGlue/ |
Wayne ONeill
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 17, 2005 - 05:14 am: |
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As the article that Roman has linked mentions, Methylene Chloride works well for seperating synthetic cement. It can sometimes take a few weeks to work (although it has worked overnight for me in other cases), but there is no risk of cracking elements due to heat. This chemical is used as a solvent-type glue for acrylic, so businesses that carry out that kind of work can be a good source of small quantities of the stuff.
Cheers, Wayne |
