[LargeFormat] Schneider Angulon 120mm

[Clive Warren]

At 9:37 am -0500 9/6/02, Ken Hough wrote:
snippety
>Optics not good. Hummm. Being a repairman who recements lenses
>I wondered what gives here. I actually had a guy (whos on this list I think)
>send me his. Angulons are cemented with Canadian Balsam. This cement
>Is refined till at anything less than 150 degrees F. it's a solid. 
>Above 150 it
>turns plastic. So this lens was decemented. Its a reversed Dagor. Three
>elements in the front and rear. The front 3 came apart in a day or two. Of the
>rear 3 only the rear inside double concave fell off right away. The convex
>cell stuck fast! It was "recemented" with crazy glue. This has happened to 4
>of these lenses I've recemented. The back 2 lenses fall off from, shock, heat,
>brute force. After I recemented it it was just fine, as are all 120s.
>Ken

Ken,

150F is pretty low - if you left the lens in a car in the US South 
West sun with the windows closed the Balsam would turn plastic! Does 
this mean that the elements move with respect to one another and when 
the temp. drops the balsam again becomes solid and transparent?

Do you use a modern cement when recementing?

Cheers,
        Clive