Best adhesive for re-cementing lens elements?

[Bayliss]

I have this Zeiss Tessar 105mm 3.5 with balsam separation that I'd like to try repairing. I've heard that tp-2500 UV glue may work for re-cementing the elements - has anyone tried this? Or know of a better option? Thanks!​

 

[4season]

I have this Zeiss Tessar 105mm 3.5 with balsam separation that I'd like to try repairing. I've heard that tp-2500 UV glue may work for re-cementing the elements - has anyone tried this? Or know of a better option? Thanks!​

I haven't done this sort of work to date, but have been thinking to try Norland NOA 60, which is specifically designed for cementing optical doublets, as opposed to mounting jewelry or repairing smartphone screens.

 

[Bayliss]

I haven't done this sort of work to date, but have been thinking to try Norland NOA 60, which is specifically designed for cementing optical doublets, as opposed to mounting jewelry or repairing smartphone screens.

Very interesting, I hadn't heard of this - are UV adhesives reversible at all? If I accidentally misalign the elements it'd be nice if I could remove the glue and try again

 

[BrianShaw]

Consider heading over to the Large Format Photography Forum and look for a recent post by Kevin Crisp. He has done this before and explained in a lot of detail no more than a couple of days ago.

 

[4season]

Very interesting, I hadn't heard of this - are UV adhesives reversible at all? If I accidentally misalign the elements it'd be nice if I could remove the glue and try again

You'll want to inquire with the manufacturer for that info.

 

[Bayliss]

Consider heading over to the Large Format Photography Forum and look for a recent post by Kevin Crisp. He has done this before and explained in a lot of detail no more than a couple of days ago.

Ah I'll take a look, thanks

 

[OAPOli]

I tried synthetic Canada Balsam (for mounting slides) but after three weeks dry time I could still push the lenses apart. Got a tiny flask of Norland NOA61 adhesive from eBay instead. But then you need a good UV source to cure it. I think it dissolves in MEK, Methylene Chloride or acetone but I didn't try. I used v-blocks to centre the elements.

Edited to add. You should consider if it's worth the effort to re-cement the lens. It looks severe in your case but it generally doesn't affect flare response or sharpness. The air new airspace is tiny at ~250nm and causes mostly an uneven transmission pattern due to light bouncing off the new air/glass boundary.

 

[Nodda Duma]

I repair separation on the side to help out my fellow photographers. I use a laser alignment station that I custom built to realign the crown and flint (important to get centration accurate when rebonding).
I am a lens designer by profession and run the engineering department at one of the U.S.'s largest optical shops.
If you decide you'd rather have it repaired by someone else, feel free to reach out to me.

Regards,
Jason