Any tips on how to repair lenses with Balsam Separation?

[manfrominternet]

Hi all,

So I bought two lenses suffering from Balsam Separation on the cheap that I would like to try and fix. Since they were bought cheaply, I’m not worried if I totally destroy them. The inner-rear elements that had been cemented together with Balsam that has since separated and has created somewhat of a foggy haze inside that would absolutely affect shooting.

As far as I have researched, here are the general steps that were recommended to take when repairing a lens with this type of damage.

1.) The tools needed for this are: a spanner wrench (to unscrew the the rings holding the lens elements), Canada Balsam (to reglue the glass elements), double boiler (to boil the balsam-cemented lens elements), lots of microfiber cloth (to line the double boiler so that the glass elements don’t scrape/scratch against the metal of the double boiler as it’s boiling), and gloves and a super clean environment (for obvious reasons).

2.) Unscrew and remove the problematic balsam-separated lens element(s). Mark a line along the side of the balsam-separated lens elements (so that you know how to assemble it back together), and put the lens elements in double boiler lined with microfiber cloth, and put in a good amount of room temperature water.

3.) Heat up water slowly - with balsam-separated lens element inside - until it boils. If boiled too fast, you run the risk of cracking the glass.

4.) After anywhere from a few minutes to a few hours, remove lens element from boiling water and let it cool down a little bit for handling. The lens elements, after being boiled, should separate easier.

5.) After separating lens elements, clean thoroughly and let dry.

6.) Now put on a little bit of new Canada Balsam on one of the elements and “sandwich” lens elements back together, squeezing out any bubbles, using the lines you marked earlier as your guide.

7.) Wait a few hours or a full day and reassemble the lens.

This is my basic understanding of how to fix a balsam-separated lens.

Do you guys/experienced pros have any tips or suggestions?

Many thanks!