Re-cementing lens elements question.

[Gerald C Koch]

I would not use anything other than what is used to polish telescope lenses and mirror blanks. That is cerium oxide and it can be purchased from sites that sell telescope parts.

Besides Canada Balsam you can also use Venice Turpentine. This is also a natural resin that is water white (unlike Canada Balsam) and also has the advantage of being soluble in alcohol.

 

[Tom1956]

Well I can tell you Ultra Brite toothpaste doesn't work. I'm convinced the front surface of this lens got itself etched somehow. Back in the junk box this Rolleiflex goes. I refuse to believe this lone single little front element, already extracted from the camera and ready for polishing, is worth 225 dollars of time and materials. It would probably spend 5 minutes on the polishing bench, and into the coating chamber. MY money doesn't come like that.

 

[desertrat]

If you have some time on your hands, there are some old amateur astronomy books on telescope making that have info on how to make small lenses. You can make a lap form fitted to the front surface of your lens and polish it yourself.

The book title is Amateur Telescope Making by Albert Ingalls, published by Scientific American. There are three volumes. Books II and III have information on small lens making for eyepieces. The polishing info should work.

I bought the set from an online used book seller. Some of this information might be downloadable from the internet.

If a lens has been exposed to water, sometimes it develops a thin layer of alkaline mineral deposits on the outside surface that cannot be cleaned off with the usual glass cleaners. An acid cleaner might work. Try warm vinegar first, followed by hydrochloric acid if that doesn't work. Vinegar has worked for me to clean these deposits off old microscope slides that had been in storage for many decades. Windex and ammonia didn't work at all.

 

[John Koehrer]

The polish I use is Maguires. It's used in polishing automotive bits.
Toothpaste(I use Colgates) can be a bit more aggressive.
The buffing compound used by hand shouldn't(?)be any worse I've never tried it. If you want to give it a whack even using a wheel may work. Depends how frustrated you get.

I'd try by hand first.