Any suggestions to re-balsam lens cells...? or I'm dreaming!

[Miguel Coquis]

Hi there !
Will much appreciate any help to find a way to save a lens cell from suffering "separation" (balsame I suppose).
Big heads (and old wolves, also owls !!!)) might have an idea of how or who or where, avoiding making a hole on pants pocket...
Lens is a very nice Tessar barrel 500mm with a beautiful iris opening particularly intersting for portraits.
Thanks in advance,
MAC

[Steven Tribe]

Is this one of the many Krauss versions of the 500mm Tessar?

For you, my friend, the cost would be mostly postage!!

[Miguel Coquis]

Wow !
That brings hope. It is in fact a Carl Zeiss Tessar portrait aereal lens f:5
It is relatively light weight which represnts a must when working ulf.
Any more data, please ask.

[Kevin Crisp]

It doesn't look like balsam failure to me, that is not the usual look or pattern.

Your choices are to live with it or recement it. As to the latter, your options are professional (Focal Point in CO) or do it yourself.

Can you get the affected element out of the mount?

[Miguel Coquis]

Looks more like kind of glue. Will try to dismount rear to see if affected element can come alone.

thanks !

[Jac@stafford.net]

Separating balsam cemented lenses is as easy as placing them in water and gently raising the temperature until they slide apart. Rinse in water as hot and done.

Centering them for recementing is a real challenge. Suggestions from others would be appreciated.

[Steven Tribe]

I think it is an early synthetic glue, which often shears like this. Replacement with balsam is more reliably done than with UV glue.

I wish one could do the separation as jac describes! It can take up to two weeks with nasty solvents. Hot water over a long time may (and does!) cause horrible damage.

Lens designers did think about making glueing easy and there is always a "best sequence" for complex lenses.

[Miguel Coquis]

Separating balsam cemented lenses is as easy as placing them in water and gently raising the temperature until they slide apart. Rinse in water as hot and done.

Centering them for recementing is a real challenge. Suggestions from others would be appreciated.

I am not sure of trying...
Included are few Pics for the affected element. I have to say how much I am impressed of the fine craft on the construction of this lens.
Very fine tiny little screws retaining rings at different levels, everything comes alone once them unscrewed. And the glass is like a "gem".
So, what kind of cement, who would provide it ?
And centering for recementing...
This should probably must go to Denmark

[Steven Tribe]

Separation system is the same for balsam and synthetics.

The problem with water is that it is absorbed into glass and is full of very active H+ and OH- which react with the strange combination of chemicals that go under the name of optical glass.

[Miguel Coquis]

I think it is an early synthetic glue, which often shears like this. Replacement with balsam is more reliably done than with UV glue.

I wish one could do the separation as jac describes! It can take up to two weeks with nasty solvents. Hot water over a long time may (and does!) cause horrible damage.

Lens designers did think about making glueing easy and there is always a "best sequence" for complex lenses.

Steven, can you develop a little more about replacement with balsam being more reliably done than with UV glue.
Many thanks !