One way to fix lens separation

There are quite a lot of posts that describe how to fix the Canada balsam problem.
But I couldn't find anything related (or useful) to modern Epoxy / UV glue, and too bad, I got some of those lens on hand, so ... lets do something.

What I got is Rodenstock Apo Rodagon 300/5.6 Enlarger len, both front and rear element has the len separation problems.
http://www.pbase.com/jack_hui/image/127380923.jpg

Lens in water, and ready for heat up.
http://www.pbase.com/jack_hui/image/127600046.jpg

I heated it up until it boil, and then cool down for 10 mins, you can see the rainbow get larger!
http://www.pbase.com/jack_hui/image/127600048.jpg

Second round, re-heat and cool down ...
http://www.pbase.com/jack_hui/image/127600049.jpg

After 10 cycles, you can see ....
http://www.pbase.com/jack_hui/image/127600050.jpg

Well, until the rainbow is disappear, let the len cool down in the water, and you are ready to re-glue. It took me one hour to separate the lens, quite fast in my standard!
http://www.pbase.com/jack_hui/image/127380922.jpg

I will just skip the re-glue, and finish ...
http://www.pbase.com/jack_hui/image/127380924.jpg

Same to my Contarex 85/2 front element, easy job!
http://www.pbase.com/jack_hui/image/127380100.jpg

http://www.pbase.com/jack_hui/image/127380101.jpg

http://www.pbase.com/jack_hui/image/127380102.jpg

http://www.pbase.com/jack_hui/image/127380103.jpg

Before I find out boiling water can do the job, I had tried to soap into the solvent, but after one week of solvent-spa, nothing seems to work. I had also tried to heat the lens in a oven, it works, but ..... the % of breaking the glass is quite high.

I think I seen this in HKLFC? Anyway I used portable oven to warm up the glasses and separated them easily; then used Acetone to clean up the mess.

Yes, I did post in HKLFC.

Is ur Len using Canada balsam or modern epoxy/UV glue?

great stuff jack

Very interesting Jack. I have two Rodenstock lenses with separation and I may now try to repair the Sironar.

Ian

Did you "skip the reglue" or did you rebalsam or reglue and with what glue or balsam? Bernie

I did re-glue the len, but I didn't show it here. My hand was full of mess, didn't want to hold my cell phone/DC .. hahah!

I use UV glue for modern len, and canada balsam for brass len.

Jack, the elements you were trying to separate, were they bonded with Canada balsam, and if so, are you saying that the solvent didn't work - acetone, I presume. I've a couple of lenses that need re-cementing. Fortunately I've got a couple of rubbish lenses to try with first.

J.

I am now boiling a Zeiss 50mm. f1.5 Sonnar (Contax) postwar, presumably UV glue, and ask who sells it and what is it called. It was a cull lens: I just finished "hand-machining" the mounting -camera attaching bayonet and hope to separate the rear and center assemblies (the front element is a single lens).
Please, what is the UV cement called and who sells it, presumably on line?
Thank you,
Bernie

They were originally bonded by modern UV glue (or epoxy?), and I believe that they are quite strong to dissolve by acetone.

One type of cement that I used is this
http://www.optical-cement.com/cement...l#anchor669157

Would index matching gel (as used in fiber optics) be suitable to interfacing two lens elements as well?

Jack,

Reviving this thread for a short post : I've just solved the separation problem on the rear group of my Sironar 135 thanks to you, although in a simplified way :

I unscrewed and took out the two outer (glued) elements of the rear group, where the separation occurred (unilateral, 3mm wide, amber)colored).The sides being black, I checked with solvent (turp) that it was just paint and not a fine metal casing - so far, so good. My strategy was to remove the paint , at least at the junction of the two elements, to allow melted balsam to seep out during heating, but I tried a first run in the boiling kettle just so, during 10 minutes.

Taking out the boiled element, I noticed the separation mark had changed shame, and somehow thinned out. I pressed the two sides together, and it seemed to me that the separation receded. So I put the elements to the boil, 10 minutes again and pressed the sides immediately on taking the element out.

It worked. I think luck allowed me to spread the melted balsam uniformly between the two components of the element. Well, at least, it does not show any irisation anymore.

I painted the sides back with black DVD marker (water- not solvent-based), let tie element dry, cleaned and put it back in the rear group mount with the retaining ring (the element was now completely cold, of course).

I am not sure this will last, but at least I know the first part of the modus operandi now, so I'll resort to re-glueing the two parts if need be, but I wish I could avoid this since the contact surface is plane, not curved, and the two parts don't have the same diameter, hence a possible centering nightmare...

But as I said, so far, so good. Thanks for the advice, I would never have dared boil lenses !!! :)

Well ain't that slicker than snot on a doorknob!

I have an old Nikkor 35 f2 the needs some recementing.

Jack, what black paint did you use on the sides after recementing..?

Sally Mann just called and she's PO'ed!;)

If the diameter of the two elements are the same, they can be aligned by gently clamping them between two "V" shaped pieces of material. I'm using 3/4" aluminum angle 3/4" tall and a small clamp.
It's gonna look something like this < O > where the arrows are the angled aluminum and O is the elements being aligned. Obviously the angles will be in contact with the sides of the elements.

Quote:

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Originally Posted by John Koehrer

If the diameter of the two elements are the same, they can be aligned by gently clamping them between two "V" shaped pieces of material. I'm using 3/4" aluminum angle 3/4" tall and a small clamp.
It's gonna look something like this < O > where the arrows are the angled aluminum and O is the elements being aligned. Obviously the angles will be in contact with the sides of the elements.

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In case the elements are not of the same size (case of my Sironar), I would have used modeler's hard latex to make an imprint of the original assembly, then use it to hold the two unglued / reglued lenses It should work and, if you have taken the precaution of making an external enclosure of Lego or something of the kind (rigid) to contain the latex when making the imprint, it should be reasonably precise.

Well this is all very interesting-
particularly the idea that I might not need to completely dismantle the cells-

However, a problem- the two lenses that could benefit from this treatment have cells that are difficult to get at-

One is a Suter Aplanat, and the group seems to be crimped, or bonded, in.
Does anyone know how to remove it from the brass, or might it be possible to boil the complete assembly? If it were, that might actually be the favoured approach-

The other lens is more problematic, and might deserve a question in a dedicated thread...

Glad I found this. I've a 600mm APO Voigtlaender Skopar that need this done to it. Never had any luck with the later cements. Wrecked a 240mm f5.6 Rodenstock messing around with it. Hot water? go figure.

Joseph - I redid a big Suter aplanat (A no. 4). I spent hours gouging out a channel to remove what I thought was a lathe turned down edge. Finally, I realised that there was an L shaped washer where the protruding edge had been pushed down inside the barrel casing edge!!
Completely impossible to see - even with the black enamel removed. It might be worthwhile checking yours for the same assembly method.
I don't think this warm "manipulation" will work with balsam. The balsam will be discoloured by now and the separated solids will prevent movement.

Thanks Steven-

It sounds like I'd be better off leaving it as it is-
just stopping down by one removes the offending edge-

It would be good to re-cement, not least to improve the value, but a description that includes 'some separation' might be preferable to one that reads 'gouged'...

Re-reading, removing the black paint would seem to be an important step-
impossible to verify with the group contained within the brass assembly...

How would I mount a smaller lens on top of the bigger ones...I'd have to center them very well?

This will have to be moved over to the "new" DIY section.

Mounting a smaller lens on top of a larger lens is not difficult. This is quite a common construction, for instance, Protar series VII. The spherical surface will fit precisely in the "hole". Just press home around the edges until the edge of the smaller lens has the same distance from surface of the larger lens.

I've done a number of lenses with the boiling water trick, until I discovered furniture stripper is less stressful (both for the glass and for me). I just put the lens assembly into a glass jar with a tight lid, enough MEK-based stripper to cover plus a bit, and let it do it's magic. On a large modern UV-glued lens, it might take as long as a week, but eventually I swirl the jar a bit and find the lenses are floating separately. A judicious poke with the tip of a pencil might speed up the separation a bit, and the advantage of the stripper is that the lenses only need a minimum of wiping to clear the gunk off, and a rinse in alcohol before re-gluing.

I was going to start a new discussion but since this one's been revived -- thanks, Albert -- here goes.

Years ago I was given a 58/5.6 Grandagon ex-Graflex XL. The glass was clean in the sense that there were no scratches or fungus but both cells had major separation. Both had rings of fire around the periphery, the rear cell had silver spots near the center. Many Rodenstock lenses from that era have similar separations.

I tried it out anyway. It shot quite well and is one of the shortest lenses that will focus to infinity on a 2x3 Pacemaker Speed Graphic. Unfortunately putting it on the camera is a pain because the rear cell is too large to pass through the front standard. The procedure is: unscrew rear cell, attach board with shutter and front cell to the front standard, put the rear cell back in the shutter from behind the camera. Reverse to take the lens off the camera.

After I got 65/8 Ilex that went on the camera without all that fiddling I put the Grandagon in the drawer. I recently took it out. It seems to have healed itself. The rings of fire are nearly gone and the silver spots in the rear cell are nearly invisible.

This is not supposed to happen. Separation is permanent. Do any of you have badly separated lenses that seem to have healed?

Short answer is no. But I have only experience with Balsam, where entry of air means that the balsam degrades into a whitish coating on the two lens surfaces. When the balsam is still in good condition, when warmed it will become more fluid and expand a little and could "repair" edge damage.

But please don't try with hot/boiling water. The heat transfer into the glass is very rapid with water and you create internal stress. Use an oven.

Separation with synthetics is a very different barrel of fish. It is more loss of adhesion with air gaps in the realm of light's wavelengths - hence Newton's rings. I can easily imagine this might heal itself. The flecks you mention sound like macro-crystal growth, which I have also seen in balsam. Crystals can also change in appearance.

I used acetone, fingernail polish remover. Removed lens cell from lens and soaked it for about a week. I could see the balsam dissolving as I checked it daily. Eventually slid apart easily.

I managed to get the lenses out and separate them by boiling method (very easy). Now a little acetone to clean up and then on to cementing back.Attachment 154882Attachment 154883Attachment 154884Attachment 154885

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Quote:

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Originally Posted by Dan Fromm

I was going to start a new discussion but since this one's been revived -- thanks, Albert -- here goes.

Years ago I was given a 58/5.6 Grandagon ex-Graflex XL. The glass was clean in the sense that there were no scratches or fungus but both cells had major separation. Both had rings of fire around the periphery, the rear cell had silver spots near the center. Many Rodenstock lenses from that era have similar separations.

I tried it out anyway. It shot quite well and is one of the shortest lenses that will focus to infinity on a 2x3 Pacemaker Speed Graphic. Unfortunately putting it on the camera is a pain because the rear cell is too large to pass through the front standard. The procedure is: unscrew rear cell, attach board with shutter and front cell to the front standard, put the rear cell back in the shutter from behind the camera. Reverse to take the lens off the camera.

After I got 65/8 Ilex that went on the camera without all that fiddling I put the Grandagon in the drawer. I recently took it out. It seems to have healed itself. The rings of fire are nearly gone and the silver spots in the rear cell are nearly invisible.

This is not supposed to happen. Separation is permanent. Do any of you have badly separated lenses that seem to have healed?

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I'm hoping that the bad lens separation will turn out ok. So far so good, and I will move on to cementing the lens next after a light cleaning and feather light polish.

Quote:

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Originally Posted by Albert A.

I managed to get the lenses out and separate them by boiling method (very easy). Now a little acetone to clean up and then on to cementing back.Attachment 154882Attachment 154883Attachment 154884Attachment 154885

Sent from my SM-N920T using Tapatalk

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Sent from my SM-N920T using Tapatalk

I have done this many times in the past, but have never used water, instead used cooking oil. I found that oil held the head (up to about 300F) without burning and you could leave the elements in the oil until everything cooled down to room temp without danger of hurting the glass. The oil also appeared to have some solvent properties that made either balsam or epoxy come off easily. I use either brake cleaner or acetone to clean the lenses once cool, then UV cement to recement. I have a project coming up in the next month to do a hasselblad 120 s planar with front separation.

Obviously works in a pinch, but a more robust method:

100 parts Methylene chloride. 15 parts methanol, and 3 parts ammonia (26% conc) is a gentler / better solvent for removing balsam and uv adhesives. Balsam takes about 1-2 days. Modern stuff takes 1-3 weeks. No risk of thermal shock / stress with this concoction, and a new bond joint will last much longer than reflowing the old. As a lens designer I can say your luck successfully separating as described will not last forever.

Btw re-cementing a lens with UV or other modern adhesive when it originally used balsam may noticeably change the optical performance.. especially true in faster optics. Just so you’re aware. Best to use like-materials to repair.

Speedball India Ink painted on works fine for edge blacking.

I've a big Ektar that needs this treatment; where are you getting your Canadian Balsa, Kramer?

On reflection, I think I have a jar of this I bought for use in an oil painting medium.

Does age matter if it's still clear?

Cheers

Methylene Chloride (Old fashioned paint remover) is a very nasty item(for the user) and is no longer available in most parts of the world. And the inclusion of ammonia reminds me that I have lost two lenses to devitrification when using aqueous based separation well away from pH 7!

Canada balsam looses its solvent. - even in well sealed containers. If it remains only slightly yellow, it can be made more fluid (ad libitum) using xylol.
The easiest source of CB is in drop spout equipped small plastic bottles made for slide preparation by microscopists.

There are longer - and better!- threads about separation etc. here. I would describe the first part of this thread as promoting a very dangerous and shoddy method.

How do you know you have lens separation? What does it look like?

Quote:

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Originally Posted by Alan Klein

How do you know you have lens separation? What does it look like?

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The classic manifestation is Newton's rings. Look it up.

Quote:

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Originally Posted by Steven Tribe

Methylene Chloride (Old fashioned paint remover) is a very nasty item(for the user) and is no longer available in most parts of the world. And the inclusion of ammonia reminds me that I have lost two lenses to devitrification when using aqueous based separation well away from pH 7!

Canada balsam looses its solvent. - even in well sealed containers. If it remains only slightly yellow, it can be made more fluid (ad libitum) using xylol.
The easiest source of CB is in drop spout equipped small plastic bottles made for slide preparation by microscopists.

There are longer - and better!- threads about separation etc. here. I would describe the first part of this thread as promoting a very dangerous and shoddy method.

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Agree on all accounts..though the concoction is straight from Norland and my experience in the optical shop doing this is a bit different than yours (if you do the math, you find it’s only 0.78% ammonia)

Quote:

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Originally Posted by Dan Fromm

The classic manifestation is Newton's rings. Look it up.

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Yes - for modern UV synthetic glues where there are very small distances between the hard glue surface/air space/lens surface.

NO - for Canada Balsam separation. The balsam never becomes a homogeneous solid, so separation is gradual. Some solids are deposited , which can give a general yellowing to the edges.

Quote:

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Originally Posted by Steven Tribe

Yes - for modern UV synthetic glues where there are very small distances between the hard glue surface/air space/lens surface.

NO - for Canada Balsam separation. The balsam never becomes a homogeneous solid, so separation is gradual. Some solids are deposited , which can give a general yellowing to the edges.

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We both missed another manifestation. I once bought a 16/2.5 Zeiss Luminar -- yes, this is a large format lens -- that appeared to have been baked while vertical. There was balsam puddled around the front element and visible voids between the cemented elements.

Quote:

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Originally Posted by Dan Fromm

We both missed another manifestation. I once bought a 16/2.5 Zeiss Luminar -- yes, this is a large format lens -- that appeared to have been baked while vertical. There was balsam puddled around the front element and visible voids between the cemented elements.

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Actually the Luminars like the MComponons and other lenses designed for true macro work would work on many different formats. If I remember correctly, when we sold the Luminars the 16mm on a 45 Technika gave over 20x magnification. Sold a lot of them as both the Zeiss Voightlander and the LInhof distributor until stocks were depleted.

Quote:

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Originally Posted by Steven Tribe

NO - for Canada Balsam separation. The balsam never becomes a homogeneous solid, so separation is gradual. Some solids are deposited , which can give a general yellowing to the edges.

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I don't understand this. Ok, the canada balsam may not be a solid. But the glass is. So you have separation or not. The newton rings are not dependent on how slow the separation evolves, only on how far there is separation with air between the elements.

There is really very little separation with air spacing development when Canada balsam begins to break down. There are some some small areas close to the edge but by then there is an opaque sandwich of granular ex-balsam.

I have never tried to redo a complex modern lens, but have had a number of the Newton ring sufferers through my hands. The UV glue remains clear, in one piece and the connection with a glass surface is lost over a good percentage of the lens. I don’t know whether the interference comes from the increased gap between the lens surfaces proper, or the gap between the glue (which acts like an extra plastic lens) and “uncovered” lens surface.

The distance between the separate rings (or the width of the rainbow lines) is related to the wavelength and distance between the two surfaces. But others will correct me as my optics was a very long time ago!

Quote:

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Originally Posted by Steven Tribe

There is really very little separation with air spacing development when Canada balsam begins to break down. There are some some small areas close to the edge but by then there is an opaque sandwich of granular ex-balsam.

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Ok, so you mean that when canada balsam let go, it doesn't really forms air space but it kind of swells and its optical properties change to opaque.

I did have 2 lenses with canada balsam separation and they had some kind of "iridescent glow" over a large surface, starting from the edge. Don't know how to describe it better. Different from newton rings. Might have a photo of it somewhere.

Hey Steven,

It’s due to the newly formed airgap. The index difference between adhesive and glass is not significant enough to form visible Newton rings.

-Jason

Quote:

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Originally Posted by Steven Tribe

There is really very little separation with air spacing development when Canada balsam begins to break down. There are some some small areas close to the edge but by then there is an opaque sandwich of granular ex-balsam.

I have never tried to redo a complex modern lens, but have had a number of the Newton ring sufferers through my hands. The UV glue remains clear, in one piece and the connection with a glass surface is lost over a good percentage of the lens. I don’t know whether the interference comes from the increased gap between the lens surfaces proper, or the gap between the glue (which acts like an extra plastic lens) and “uncovered” lens surface.

The distance between the separate rings (or the width of the rainbow lines) is related to the wavelength and distance between the two surfaces. But others will correct me as my optics was a very long time ago!

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