How to Breathe Life into a Doublet

[Liquid Fusion]

"Curiosity killed the cat, but knowledge brought it back."

Hi. Bought a Summitar 50mm. Had a "fingerprint" inside the front lens group. Managed to separate the lens from the front lens group and even open the outer ring housing the 1st (doublet) and 2nd (single) lens groups. Whats needed here is mention I boiled the front lens group in water, thinking it might melt any cement bonding the outer ring to the Front Lens Group. Right now, separated lens glass is super clean and nice. Problem: the front outer ring doublet is sealed / burnished. Balsam melted and had nowhere to go: outer doublet Lens is all blotched. If you can open the doublet, then the solution is easy: boil the doublet glass, separate glass elements, dry, clean balsom off with solvent, dry, center in V Block, cement, reinstall in doublet outer ring housing. Thus the reason for a pro: 1st lens doublet being burnished can't be opened without a lathe.

Know anyone who can do this? Thanks // Link to photos of lens as it is now

BTW the "fingerprint" melted away. 2nd lens group in the Front lens group is very clear. The outer lens is too. Once the doublet is opened and the old balsam removed, anti-reflective paint is added, and a new lens coating it applied - this will be a great Summitar!! Just need to find the right person to do this work: a lens master who loves a challenge and is not too expensive.

 

[Robert Lai]

I would probably give Don Goldberg a call and see what he suggests.
Ken Hansen can probably rescue you also, at a cost.

 

[Liquid Fusion]

Fixed properly, more expensive than a new lens. Boiling lenses apart is somewhat hit and miss, sometimes they crack.

OH MY, boiled it did you?

I always read Heating can crack a lens. Boiling never does.

One way to fix lens separation (Boiling Lens) - in water (until it confesses and separates)

 

[Liquid Fusion]

Well you can't believe everything you read!
I had one of best repairmen around crack a lens boiling it, he was able to find a replacement element and all was well, but for sure they can crack.

Think the trick is bring water to boil (stove top gas burner) - then turn off the heat / flame and let the water cool with lens in the water.

 

[Liquid Fusion]

I would probably give Don Goldberg a call and see what he suggests.
Ken Hansen can probably rescue you also, at a cost.

Thanks. Don Goldberg / DAG sent me a nice email:

<<< Yes, the front lens element group in the Summitar lens de-cements very easily. The rolled over lip of the lens barrel needs to be partially machined & then the front lens elements need to be pressed out. I was trained at Leitz in Wetzlar, Germany as a Fine Mechanic & have all the cutting machines to do this type of work, feel free to send your lens to the address below ...>>>

He doesn't recoat lens, but just having this lens fully taken apart, cleaned, then reassembled will be amazing!! This Summitar (1949) must be a factory reject as there was a "fingerprint" inside the 1st lens group / doublet. The glass seems clear. No marks. No haze. No fungus. A good thing to work with when it will be put together again the right way!!

 

[Sarcophilus Harrisii]

What is the likelihood of Milsolve Decementing Solvent penetrating the melted balsam and freeing the pieces involved? Some product details here.
Separating bonded pieces is not a task I have tackled yet, but from my reading about the subject, I've always been inclined to try chemical methods where practicable instead of heat, in the first instance, if I need to carry it out at some point. It avoids the risk of breaking glass.

I am not sure what effect the solvent would have on things like the makers name and lens details on the front ring. You'll need to do your homework first, before you immerse items like that in it. But, FYI, if you've not heard of it.
Cheers,
Brett

 

[kuuan]

a doublet out of my CV 2.5/75 isn't clear and I am quite sure that is it separation. It looks like this:

it was easy to get the doublet out of the lens and I had tried once to separate it's two elements by placing it on top of a 100W lamp, or was it only a 60? anyway I was not able to get them apart and have not dared to heat it in an oven or boil it..yet.
Has anyone experience with this very lens? What kind of bond would it have to make it either likely to be separated or not? Any advice on how best to get it separate would be most welcome!!