replacement of Canada Balsam?

[jack_hui]

Hi,

Just want to fix my old petzval len (for fun only). I have already separated the lens elements, but not sure which glue should be use, Canada Balsam (I can find it from ebay) or other UV-glue? any source?

I am working in an optical media factory (e.g. DVD), the bonding lacquer we are using
is UV-glue, but I am not sure whether it is usable for bonding the glass ....

Thanks
Jack

[eddie]

use canadian balsam. more forgiving than the UV stuff.

keep us posted.

[jack_hui]

Eddie,

Any idea on how to harden the Balsam ?? should the balsam heated up first (e.g. 150degC), apply a small drop between the element and let it cool down naturally?

Thanks
Jack

[eddie]

i do not know for sure....or i have forgotten. i have been wanting to do this for some time now. after speaking with several people that do it i have decided CB is the best method for me to try. i will do it soon.

i have a friend that has re cemented a few lenses for me with the UV stuff. works fine. no room for error once you hit with UV. another down side is that the UV stuff does not seem to keep long....it gets hard.

i will find out how to dry it/harden it. (air? and time?)

eddie

[Glenn Thoreson]

I use UV cure optical cement from Edmund Optics. I just got a fresh bottle of glue that works really well. Using sunlight, you have enough time during exposure to keep everything in line. About 20 seconds to initial set. I don't know how fast it sets under a UV bulb, as my bulb doesn't seem to putout the right wave length. The last glue I used would flash set under that bulb. UV glue is expensive. My new 1 oz bottle was 25.00 plus shipping at a ridiculuos rate, but what's a guy to do? Can't get it at the grocery store.

[jack_hui]

I use UV cure optical cement from Edmund Optics. I just got a fresh bottle of glue that works really well. Using sunlight, you have enough time during exposure to keep everything in line. About 20 seconds to initial set. I don't know how fast it sets under a UV bulb, as my bulb doesn't seem to putout the right wave length. The last glue I used would flash set under that bulb. UV glue is expensive. My new 1 oz bottle was 25.00 plus shipping at a ridiculuos rate, but what's a guy to do? Can't get it at the grocery store.

I just checked with the bonding glue for our DVD machine, the glue seems to be a bit "yellow" ... but it will turn to clear after it expose to UV lamp. But I have no way to check how "clear" is it ...

Is the color of optical cement from Edmund Optics, also appear a bit yellow?

[jack_hui]

i do not know for sure....or i have forgotten. i have been wanting to do this for some time now. after speaking with several people that do it i have decided CB is the best method for me to try. i will do it soon.

i have a friend that has re cemented a few lenses for me with the UV stuff. works fine. no room for error once you hit with UV. another down side is that the UV stuff does not seem to keep long....it gets hard.

i will find out how to dry it/harden it. (air? and time?)

eddie

Just ordered one bottle of Canada Balsam from ebay, hope to get ur answer soon!

[John Schneider]

Search the archives, e.g., http://www.largeformatphotography.in...ad.php?t=54349

[Brian Stein]

Also have a look at:

http://www.atmsite.org/contrib/Sapp/LensGlue/
http://www.optical-cement.com/
http://www.skgrimes.com/popsci/pops/index.htm
http://www.freelists.org/post/rollei...menting-Lenses

The advantage of canada balsam is ready reversibility: nice if you are new to this sort of thing, and still used by some folks when experimenting

good luck

[Steven Tribe]

I have just been in the freezer to check my UV 65 glue from Edmonds. Looks fine even though it is 2 years past the last date. Perhaps slightly less viscose but it will get more fluid as it warms up. Methylene chloride (CH2CL2) will remove it quite easily. Even separating old Balsam can be a problem.