Fixing lens delamination - first try

I mentioned it from time to time that the Fujinon video lenses i got with several vintage video cameras all suffer from one problem - one of the laminated lens elemens delaminates, resulting in a blurred image with low contrast.

Interesting enough, there was not a single exception yet. The last one i got first had fungus, i didn't see the delamination, but after cleaning the fungus problem, the slightly milky look through the lens revealed that it also is no exception.

Beside all those Fujinons, i also have 2 Canon and 1 Schneider video zooms, they don't have those issues. Very interesting. So a while ago, i decided to give relaminating a try on one of the Fujinons i don't really need. It's a hard challenge consisting of first separating the elements, which is not too hard with the old canada balsam, but most people will tell you it's nearly impossible with the more modern epoxy based cements. If you separated and cleaned the lenses and the glass is okay, the next challenge is cementing it back together. Most people use canada balsam, some use the modern epoxy based stuff which is even harder to get for normal people, but one out there uses simple consumer glass glue. This is what i decided to give a try and ordered a while ago.

Now, with another new camera, i had the chance for a first try. The filter block in front of the color separator looked very ugly. Too bad i didn't make a photo of this, but i started working on this too spontaneuously yesterday evening, so i forgot. But meanwhile, i have some progress i need to share with you.

Yesterday evening, i have thrown this 3-element filter into an acetone bath. Half an hour later, i was able to easily remove the thickest element from the stack and with the help of some more acetone and a guitar pick, it wasn't too hard to remove the remaining epoxy from it. But i wasn't able to separate the remaining 2 elements yesterday evening, so i let it soak over night. Stil no success this morning, so i carefully applied a bit more force, there was not much to lose. The problem was the blue disc, which is the IR filter and this one is very thin, so it can easily break. But everything went fine, after patiently pushing around the seam with the fingernails it suddenly came off.
Same procedure with acetone and the guitar pick to clean all the surfaces and then a closer inspection. The IR filter definitely had some damage, but at least the center was mostly clean. I inspected a bit with the microscope, i wasn't too happy with what i have seen, but still better than before with the bubbles in the dissolving cement.

So let's go for re-cementing it. I never worked with this glue, so i was a little bit nervous. Cleaned all surfaces with the LensPen, compressed air to blow off remaining dust, a drop of the glue, pushed the first 2 elements together and got a horrible mess. Sure. That was too much glue. If i knew how evil this stuff stinks and what mess it leaves, well, everywhere, i would have use less :) But okay, after aligning everything and washing my hands about 5 times during this, cleaning the desk and so, the 2 pieces were together. I couldn't judge the quality because everything was contaminated with this glue. I didn't want to risk damaging the only important area - the area between the two pieces. They say 5 minutes until it's a little bit stable.

And they said 24h in daylight to harden. Well. Daylight. Maybe visible again in March? Okay, let's see how it works out tomorrow...

1.5h later, i decided to clean the outer surfaces and noticed that really nothing changed, the glue was still as soft as it was 1.5h before. And tweaking the whole thing to clean it didn't seem to damage the joint between the glass surfaces. So i cleaned it and decided to put the third piece in place also, looks like the glue is not so critical. And it really isn't. This time it was not enough glue, i added some with the finger, shifting the elements around, i did absolutely everything you would never do to get a good result :)

Then there still is this 24h daylight problem. How to i stabilize the whole thing without creating another mess with the plastic frame where the whole thing later goes? I wrapped some adhesive tape around it.

And then i had another idea. Daylight. 24h. What if i use an UV source? UHU doesn't specify the required wavelength, so i decided for the EPROM eraser, which looked plausible. To erase an EPROM under sunlight, you might need weeks. This erase needs minutes. So i gave it 5 minutes and voila - the glue hardened enough that it was impossible to shift the elements around to fix a minor misalignment i noticed. I removed the tape, cleaned the surfaces and threw it back into the eraser for another 15 minutes, which should complete the task.

Really bad that i don't have the before-photos, but the after-photos are impressive, even on closer inspection, i don't see the defects of the IR filter, maybe the glue filled enough small gaps that even this problem is gone.

Even if the separation with Acetone might have been a matter of luck, i'm very positive using the not so important Fujinon lens as my next victim for this :)
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30.11.18
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