[LargeFormat] Schneider Angulon 120mm

[Ken Hough]

150F is where it gets soft. Look at all Angulons. There is no metal shield 
supporting the optics. Thats why the rear pair drops off.
 At 150 Balsam is clear. At 228f it is clear too. But it loses some solvents 
and crystallizes. Remember those old Turner Reich lenses that are cloudy 
and yellow? Thats either poor cement or Long term heat damage. Those 
lenses are pretty great with the Orange filter they came with. I use a 12/21/28
that I would not trade for anything.
Yes I use a UV cement. Unless its really old and extremely Valuable I will 
use Balsam.
Ken

To:             	largeformat@f32.net
From:           	Clive Warren <cocam@blueyonder.co.uk>
Subject:        	Re: [LargeFormat] Schneider Angulon 120mm
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Date sent:      	Sun, 9 Jun 2002 19:02:09 +0100

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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


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        ******Ken Hough Photographic Repair******
         Specializing in Deardorff Refinishing
          Lens Recementing and Shutter repair
          Contributor to McKeowns Price Guide
                   Deardorff Section
           Custom machined Photographic items
           Text Contents Copyright 1999 KHPR
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                   Est. 1980