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Shinobi
Tinkerer
Username: Shinobi
Post Number: 1
Registered: 09-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 17, 2012 - 06:58 pm: | 
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I currently have two of the subject lenses, both in need of cleaning. I cannot get either one sufficiently apart. Here is the situation:
I have been able to remove the first (i.e., front most) two elements from both lenses without destroying anything so far. Bad luck for me is that both need cleaning deeper than that, into the rear elements. One lens contains a very small bug. The other lens has just a smidgen of fungus. Both lenses are otherwise in decent shape. I could rescue them, I'm certain, if I could disassemble them.
In both cases:
With the first two elements removed, and with the cone-shaped front piece also unscrewed and removed, I am down to a rather broad, black, round metal piece which appears to secure the next lens element. There are two slots in this piece, 180 degrees opposed, leading one to believe it should unscrew. But I've applied a very large amount of torque to that end and the piece will not budge. I've tried several times.
What does frighten me is that I have found here and there a substance I can best describe as contact cement or contact adhesive. If the lens was assembled, at the factory, with this cement (or adhesive) on the threads it would explain the impossibility of unscrewing the stuck piece. I've also tried to unscrew the rear most metal ring which appears to be securing the rear most lens element. It, similarly, will not budge. And I have applied a very large amount of torque, to the point where I was fearful for the integrity of the (rear) lens itself (the lens is OK, though).
I hope somebody has disassembled one of these lenses and knows the trick which currently is eluding me. Only thing I can think of is to warm the lens a bit. I've not yet tried that.
Surely there must be a secret to further disassembly of these lenses . . . I hope!! |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 380
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, September 17, 2012 - 08:28 pm: |
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You probably need some acetone to loosen the thread glue. Or some alcohol. Someone else though may know the exact solvent to use.
PF |
Shinobi
Tinkerer
Username: Shinobi
Post Number: 2
Registered: 09-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, September 18, 2012 - 05:28 am: |
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Thank you, Br1078lum, for your reply. It is appreciated.
I'm a noob to this sort of thing. My lack of experience easily could be clouding my judgement. But I only can observe that if those threads have on them the kind of adhesive/cement I found in small quantities elsewhere within the lens . . I'm sunk.
I see no way to apply solvent to the threads currently giving trouble. I can't even see the threads. Perhaps if I immersed the lens in solvent that would do the trick. But I cannot fathom an assembly procedure which would make these lenses that difficult to disassemble.
Frankly your post, while appreciated, has left me disheartened. |
Br1078lum
Tinkerer
Username: Br1078lum
Post Number: 382
Registered: 11-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, September 18, 2012 - 11:31 am: |
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You just need to introduce the solvent around the outer edge of the ring, and it will work it's way down into the threads on it's own. Just don't get sloppy with it.
PF |
Shinobi
Tinkerer
Username: Shinobi
Post Number: 3
Registered: 09-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, September 18, 2012 - 01:43 pm: |
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Understood. OK, thanks. |
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