Is it possible to fix the de-cementing in a lens?

[Teodor Oprean]

I have acquired an Optar 162 mm f/4.5 lens in which the rear doublet has suffered very obvious de-cementing. Is there anything that can be done to fix this defect?

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[Steven Tribe]

Yes!

There are threads in the DIY section. Use "Balsam" as a search word.

[Teodor Oprean]

Yes, I understand that Canada balsam is the cement used in holding the elements of the doublet together, but where can I buy the balsam? Who sells it? In what quantities? How do I perform the restoration? I have not dared to try such repair work before, so I am hesitant to ruin a lens that might work just fine as it is, even in ugly condition.

[Steven Tribe]

As I mentioned before, there are answers to all these questions and much more in the DIY threads!

I would guess that the Optar has synthetic cement - but the repair can be done with balsam.

[Jim Galli]

A 162 Optar is a great lens to learn on because if you do spoil it, they're quite replaceable and cheap. You'll have to find a way to cut into the brass that is 'rolled' around the back of the lens in order to free the glass from the barrel. A friend with a lathe is one way. Put the lathe in 'neutral' and rotate the chuck by hand as the cutter advances. Then read all the good stuff that's been written before and give it a go. Nothing to lose. I think those lenses were produced by Rodenstock which was famous for having delamination problems with that first generation non-balsam cement.

[Teodor Oprean]

Can't be Rodenstock. It must have been made by Wollensak. It's a Raptar rebadged using the Graflex Optar name.