Recementing lens element

[Jimi]

Thanks for the further comments and thoughts. Maybe I am doing it the wrong way around, but I am thinking farming it out would cost me $150-200 for the work and maybe another 50 for shipping, and I guess that is why I would be on the fence. If I was to try recementing, I think this lens is as easy as it can get (I don't say it is too easy though, many things can go wrong) - there is a threaded ring that screws out and the lens element is very easily taken out. It's also only two elements.

I would have no qualms about sending the job out if the lens was more valuable or multicoated, me risking wrecking the coating and so on. It's a balance as you say, Kuzano.

[Peter De Smidt]

Give it a shot. You could use a modern UV cure lens cement instead of the Canadian balsam.

[Old-N-Feeble]

Give it a shot. You could use a modern UV cure lens cement instead of the Canadian balsam.

That's precisely what I would do... replace the balsam with UV activated cyanoacrylic glue.

[winterclock]

http://www.popsci.com/archive-viewer...147&query=lens An old how to on re-cementing lenses. I seem to recall seeing something about re-flowing the cement on delaminated lenses by boiling them, but can't remember where.

[J. Fada]

I have done a few lenses now and it isn't all that difficult. Make sure you mark the lens before you separate the elements. I use a pin to score a line on the edge which works fine and makes it easy to realign the elements. I think you are better off using Balsam instead of the UV glue until you get some experience. I pretty much guarantee that it won't be right the first time you do it. If you use UV cement you will be cursing up a storm trying to get the elements back apart. You will need some small v-blocks. If you soak the elements in Acetone they will eventually separate. I bake the elements with the balsam in the oven for a couple of hours between the v-blocks and then when I take the lens out of the oven I make sure it is aligned and let it cool. I have restored by this method a couple of Computar enlarging lenses which are prone to horrible separation and they are spectacularly sharp now living up to their full potential.

The other down and dirty way is to bake the elements as they are melting the Balsam that is already there. If you get lucky it will fix the problem. If not, no loss. You still need to make sure they are aligned though using v-blocks. If it doesn't work they should come apart easily while the elements are warm

[Steven Tribe]

Stick to Balsam. I gives you the opportunity of doing many attempts without difficulty.
The thread I have on it is labelled:
"How I did it: new balsam for a sick RR".
This is quite extensive.

[imagedowser]

+1 on Steven..... balsam is much easier to reverse.

[Vick Ko]

NO NO NO
Never use cyanoacrylate glue anywhere around optical glass. NASA banned it from their labs.
It creeps and outgasses, and coats all other glass surfaces.

...vick

That's precisely what I would do... replace the balsam with UV activated cyanoacrylic glue.

[John Koehrer]

+1

http://www.popsci.com/archive-viewer...147&query=lens An old how to on re-cementing lenses. I seem to recall seeing something about re-flowing the cement on delaminated lenses by boiling them, but can't remember where.

I've tried this and it worked pretty easily, lots easier than separating & recementing.
Try it, boiling water isn't that expensive.

[Carsten Wolff]

So that wouldn't work on reasonably new lenses I guess then? When did the big manufacturers change from Canada Balsam (to....)? I have a few 1960 -1970s lenses that may benefit: I just don't want to try it in case modern cements start to bubble, go cloudy, or otherwise make a greater mess when heated....
I did a Canada Balsam replacement on a big old Petzval and that was actually pretty easy. The trick is to use the right amount and to center the glass properly. Still looks good after a few years; I sealed the edge about a month after recementing with black laquer to prevent humidity affecting the balsam in the long term. So +3 on Steven.