separation in a lens (Biogon35 LTM)... advice or solution needed...

[photovdz]

I just got a very nice biogon 35 LTM T (perfectly original) with very nice glass §no scratch on the rear lens... no scratches at all anywhere else) but suffering form separation between two glued elements. I have read somewhere that it's possible to fix the problem through a careful recementing of the element... it involves heating slowly, pressing the lens back together, and letting it cool down quietly...
so does anyone know or has experienced the process ? what are the temperrature to obtain ? etc...

please help ?

Stephan

[Santafecino]

Yow; this must be one of those things that shouldn't be attempted in the home. I'd sens it to DAG or Golden touch and get their take, because this is not a common lens and it's valuable.

Just one man's judgment.

[John Shriver]

The problem is getting the two elements perfectly centered when gluing them back together. This is really a job for SK Grimes or Focal Point Lens, I don't think DAG or Sherry are set up for centering and cementing elements.

Now, there are tricks with injecting the right oil to fill the gap, and using them as-is. Not perfect, but it does work.

[SolaresLarrave]

John Van Stelten is the only person who repairs this problem. Send him an e-mail (you can get his address from his website, which is HERE (http://www.focalpointlens.com/fp_intro.html).

Some years ago, I purchased a lens relatively cheap because it had a small separation. It didn't show, or had any effect on my slides, but I sent it to John and he repaired it faster than his usual turnaround (he was leaving on vacation and wanted to get all his work done). Again, contact him about the job.

[John Lawrence]

These people are good:

http://www.optil.co.uk/

[Rob-F]

I have used John Van Stelten for this issue. I sent him a Dual-range Summicron, and he did first-class work. So here's another recommendation for John at Focal Point. They are in Louisville Colorado, which is N.W. Denver area.