lens separation

thebbm · Joined: 11 Dec 2013 Posts: 295 Location: France montpellier

I buy a vivitar m42 17mm with lens separation in the group near the aperture ( from the rear side ).
It was very easy to remove the lens group ( 2 lenses ) with the separation and to unstick them ( boiling in water 30min. )

Now i need to clean the lenses from the old canada baum (i think) . can i use white spirite or alcohol ?

To glue them back can i use something else than canada baume ? Something that i can find easly, i need just one drop of "glue"/baume and the canada baume is sold in very too big size for me.
Why the original baume was applicate inside/between the two lenses and not just around them ?

thanks a lot

Lloydy · Expire: 2022-01-01

Do a search on the forum and you will find some excellent information on an old thread, I think it was from Klaus ? about repairing seperated lens groups. He used a commercially available glass glue, something you get in a hardware shop, instead of the original balsalm. I,m posting this from a phone so its not easy to do the search, the information is here somewhere though.

ZoneV · Expire: 2011-12-02

I use "UHU Glas" which is a special glue for glass, that hardens under UV (sun) light for lens separation repair.
I found this to be a cheap alternative to other UV curing glues like from Edmund Optics, Summers Optical and others. And for me much easier to handle than canada balm.

cooltouch · Joined: 15 Jan 2009 Posts: 9109 Location: Houston, Texas

Hey ZoneV, when you reglue lens elements using this UHU Glas, do you just push them together firmly and then set them aside for the glue to set up, or do you use clamps of some sort?

ZoneV · Expire: 2011-12-02

I did it in the lens housing.
Before this I press the elements very hard together to get the excess glue out the lens group, and clean it away. After this I put it in the lens housing to get the alingment. Clamps usually only hold on two sides, three sides would be much better. But my three-jaw power chuck from the lathe is not good for this with those theeths on the jaws.

cooltouch · Joined: 15 Jan 2009 Posts: 9109 Location: Houston, Texas

I have some small C-clamps with plastic disks on the ends. So if I were to use a clamp, I'd locate the disks on the center of each element to press them together. I can see why mounting it in the lens's receptacle for it would be important for alignment, though.