Yesterday somebody sent an email asking how difficult it was to separate and re-cement lens elements. A couple of years ago I wrote some notes and posted them to Fotomozaic. You can see them here (along with a few other notes I wrote):
Hope they're helpful. If anyone has any questions or needs a small bit of balsam, please let me know. Note: you can use the same balsam used for microscope slides. Honestly speaking, there are many different ways to successfully do this and they all will work. Some people use UV cured cement, and it will work fine, however there are reasons I don't like it (and I should mention I've repaired watches since...well for decades). If you read comments on the internet, you are likely to see dire warnings about lens element alignment. Trust me, you can use your tongue to sense proper alignment. It is able to detect differences of less than the thickness of a cat hair.
You lick cats?
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.