First I want to say Thank You to all the brilliant contributors, who provided the entertainment and insights gleaned over several months of lurking on photomicrography.net.
Back in the mid-60's I spent untold hours straining over a 1200x suitcase style Xmas scope while salivating over the Achromatic units in school for the older students. About a year ago I discovered this eBay thing and now have some 20 microscopes and many ancillary items. Just can't seem to let those once mega-dollar items go for pennies when all they need is a little TLC.
My latest bonanza is a Reichart-Jung (A.O. 150) in pristine mechanical shape but was stored badly. It's unique in that the head swivels (circa 1985+). The oculars and mirrors are clean, some surface mould on objectives (I have spare 10, 40, and 100x plan A.O.s) but the cement that joins the beam splitter needs replacing. I'd show you the composite photo I took of the cage while it was disassembled but I've no web page to host it. (I'm amazed it will pass light at all.)
The thing is... I've got Xylene, Cerium Oxide and Canada Balsam but I don't know how to soften the modern adhesive Reichart used.
I don't think Balsam would be the best for repair or if 2-part epoxy is ideal for mounting. Although a UV lamp would be great to have, it's not in cards now.
Reichart's web-store doesn't sell the assembly and even-if, it would cost more than my purchase price. FWIW the image is surprisingly clear with about 50% degradation with the 100x original objective used dry.
Will any of you kindly sages care to advise me?
Jim
Bino-prism surgery
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Bino-prism surgery
Last edited by Retro on Tue Jul 20, 2010 6:21 am, edited 2 times in total.
Hi Jim and welcome aboard!
What you need to do is get some methylene chloride solvent. This is used in carburetor cleaner and paint stripper and you really do need to wear neoprene or similar tough gloves using it and only use it outside or in an open door garage. It is very nasty stuff.
But it will soften almost anything. Soak your prisms in that. Make some fiducial reference marks so that you can put everything back where it was.
It is very important for those prisms to go back exactly where they were so that you don't get a goggle eyed headache from eyestrain.
You may be able to loosen the adhesive with a longer soak in a less nasty solvent like Toluene Xylene perhaps mixed with some acetone or MIBK.
You can recement the prisms using Loctite windshield hole repair. This is very similar to Norland blue light curing optical adhesive and I have cemented lenses with it before with success. I don't think anyone will ever get those lenses apart. It comes in a small yellow opaque syringe and you apply in in subdued light.. Then take it out in the sun and it will cure.
Here
You can buy Norland two part optical cement from Edmund scientific in small quantities. Canada Balsam is good in that it is quite demountable but is pretty obsolete for optical use.
Good luck.
Gene
What you need to do is get some methylene chloride solvent. This is used in carburetor cleaner and paint stripper and you really do need to wear neoprene or similar tough gloves using it and only use it outside or in an open door garage. It is very nasty stuff.
But it will soften almost anything. Soak your prisms in that. Make some fiducial reference marks so that you can put everything back where it was.
It is very important for those prisms to go back exactly where they were so that you don't get a goggle eyed headache from eyestrain.
You may be able to loosen the adhesive with a longer soak in a less nasty solvent like Toluene Xylene perhaps mixed with some acetone or MIBK.
You can recement the prisms using Loctite windshield hole repair. This is very similar to Norland blue light curing optical adhesive and I have cemented lenses with it before with success. I don't think anyone will ever get those lenses apart. It comes in a small yellow opaque syringe and you apply in in subdued light.. Then take it out in the sun and it will cure.
Here
You can buy Norland two part optical cement from Edmund scientific in small quantities. Canada Balsam is good in that it is quite demountable but is pretty obsolete for optical use.
Good luck.
Gene
Fantastic! That is the type of practical information I can use Gene.
What I'll do is take the cage to work (my mould & die toolroom) and apply your brilliant suggestions in controlled comfort. Shouldn't be too difficult to reposition ( wish you could see photo) and the collimating only took 3 nudges the last time.
Really appreciate your fast response, thanks.
Jim
What I'll do is take the cage to work (my mould & die toolroom) and apply your brilliant suggestions in controlled comfort. Shouldn't be too difficult to reposition ( wish you could see photo) and the collimating only took 3 nudges the last time.
Really appreciate your fast response, thanks.
Jim
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rjlittlefield
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Jim, welcome aboard! 
If your pictures are no bigger than 1024x1024 pixels and 300 KB, then you can host them right here at photomacrography.net.
Just use the "Upload picture" button while you are preparing your post.
See details here: http://www.photomacrography.net/forum/viewtopic.php?t=7 .
--Rik
If your pictures are no bigger than 1024x1024 pixels and 300 KB, then you can host them right here at photomacrography.net.
Just use the "Upload picture" button while you are preparing your post.
See details here: http://www.photomacrography.net/forum/viewtopic.php?t=7 .
--Rik
Wow that's ugly!
You probably don't need to use the Loctite product though. I was thinking of
a stereo microscope with Porro prism image erectors.
That is just one side of a splitter from a compound binoc (which is what you said) and so you should be able to use almost any adhesive to reaffix the prism to the metal mount.
The Loctite is for a glass to glass bond and has the same refractive index as windshield glass and forms an invisible bond.
Actually you might have better luck, depending on the consistency and condition of that cement, by breaking it loose with a less aggressive solvent and then letting it redry. Clean the removed prism and then replace it in the original bed of cement with a thin layer of new adhesive. This method might allow return to the original position with less nudging. If you are a tool and die maker I don't think this will be very challenging to you.
G
You probably don't need to use the Loctite product though. I was thinking of
a stereo microscope with Porro prism image erectors.
That is just one side of a splitter from a compound binoc (which is what you said) and so you should be able to use almost any adhesive to reaffix the prism to the metal mount.
The Loctite is for a glass to glass bond and has the same refractive index as windshield glass and forms an invisible bond.
Actually you might have better luck, depending on the consistency and condition of that cement, by breaking it loose with a less aggressive solvent and then letting it redry. Clean the removed prism and then replace it in the original bed of cement with a thin layer of new adhesive. This method might allow return to the original position with less nudging. If you are a tool and die maker I don't think this will be very challenging to you.
G
Looking at that rough grey epoxy (bondo?) makes me wonder if an out-gassing reaction could be responsible for the laminating cement's failure. I have another, older, model 150 (grey-enamel, tungsten bulb, inaccessible switch) with seriously reduced contrast at 40x plus, and suspect a similar condition. Have not opened the head yet. Has anyone heard of this problem in A.O.'s otherwise superb designs?Wow that's ugly!
I'll check to see if both prisms have parallel sides but it appears that if the 45° joint is rotated so that the input-egress surfaces of the splitter remain co-planar the result will be functional. My main concern is that I use cements that will play-nice when the head is buttoned-up.
I want to add that I'm thrilled to meet people who can understand exactly what I'm saying. Communication is not my forte.
Jim
I would seriously doubt an outgassing problem. This after all was not the first scope that AO ever built and these series were just monstrous sellers in fifties sixties and seventies. Here in the states they are found everywhere.
The comparable Bausch and Lomb models are unusual to see by comparison.
(Though at work I am about to scrap a very large number of them. A Flat Field version with a field flattening lens in the scope body making the objectives incompatible with the rest of the world. Also the worst lamp mount ever conceived of by man. (the 1630X pre focus
)
I think just solvate them apart and see whether the prism needs a little polish with Cerium Oxide or an UltraLap and cement them back together maybe with the loctite or sme other acrylic material. Even super glue. Give it a couple of days to cure comepletely and spritz it with accelerator. Super glue as everyone knows does outgas until completely cured.
The comparable Bausch and Lomb models are unusual to see by comparison.
(Though at work I am about to scrap a very large number of them. A Flat Field version with a field flattening lens in the scope body making the objectives incompatible with the rest of the world. Also the worst lamp mount ever conceived of by man. (the 1630X pre focus
)I think just solvate them apart and see whether the prism needs a little polish with Cerium Oxide or an UltraLap and cement them back together maybe with the loctite or sme other acrylic material. Even super glue. Give it a couple of days to cure comepletely and spritz it with accelerator. Super glue as everyone knows does outgas until completely cured.
I didn't know carb cleaner was Methylene chloride, perhaps ours (UK) isn't - or I'm thinking of something else.
If you go for paint stripper, you might try Nitromors Laquer remover, which I've used for similar purposes. It's the same stuff but much runnier , and I think penetrates better.
EDit - curiosity found all sorts of nasties used in carb cleaners, so who knows?
http://www.ehow.com/list_6029898_ingred ... aners.html
http://www.technicalchemical.com/msds/4695.pdf
Methylene chloride and its uses
Methylene chloride, also called dichloromethane, is a volatile,
colorless liquid with a chloroform-like odor. Methylene chloride is
used in various industrial processes in many different industries:
paint stripping, pharmaceutical manufacturing, paint remover
manufacturing, metal cleaning and degreasing, adhesives
manufacturing and use, polyurethane foam production, film base
manufacturing, polycarbonate resin production, and solvent
distribution and formulation.
Jolly useful stuff, but it blisters my skin quite quickly and stings a bit.
If you go for paint stripper, you might try Nitromors Laquer remover, which I've used for similar purposes. It's the same stuff but much runnier , and I think penetrates better.
EDit - curiosity found all sorts of nasties used in carb cleaners, so who knows?
http://www.ehow.com/list_6029898_ingred ... aners.html
http://www.technicalchemical.com/msds/4695.pdf
Methylene chloride and its uses
Methylene chloride, also called dichloromethane, is a volatile,
colorless liquid with a chloroform-like odor. Methylene chloride is
used in various industrial processes in many different industries:
paint stripping, pharmaceutical manufacturing, paint remover
manufacturing, metal cleaning and degreasing, adhesives
manufacturing and use, polyurethane foam production, film base
manufacturing, polycarbonate resin production, and solvent
distribution and formulation.
Jolly useful stuff, but it blisters my skin quite quickly and stings a bit.
The epoxy looks like a botched repair, courtesy of bicycle repairman, to me.
Is this the combination prism that merges the right and left? Is there a half silvered mirror beneath that looks mucked up? If that half silvered portion is damaged, it's dumpster fodder, and time to look for another head. They're cheap, and not worth repairing, IMHO.
Is this the combination prism that merges the right and left? Is there a half silvered mirror beneath that looks mucked up? If that half silvered portion is damaged, it's dumpster fodder, and time to look for another head. They're cheap, and not worth repairing, IMHO.
I am not young enough to know everything.
Gene, your advise has given me the confidence to go ahead with the repair job, thanks.
Those " Ultralap" products look really interesting. Strange that after 35 years of plastic injection mouldmaking exposure this is the first I've heard of them.
Now that you've tipped your hand regarding B & L... I recently acquired a 10x and 40x objective set in a package deal and it turns out they're from a "Balplan". Wow, they're Plan! So I stick them in a '57 Dynoptic... Can see nothing, do a little reading... Oh! they're Infinity Corrected, no problem, I'll use them in an A.O., Ha!, still see nothing. More searching and I see that a Balplan tube lens is mounted on the back of the nosepiece.
The point is I'm looking for any cheap Balplan nosepiece, otherwise I've got two handsome lenses just filling up film cans. Let me know if you can help so I can jury-rig them to a bellows for pic's.
ChrisR, thanks for the input, the chemical world is truly scary! If you're inclined, check the Wikipedia and/or MSDS on Hydrofluoric acid. That's some pretty sneaky toxin!
Jim
Those " Ultralap" products look really interesting. Strange that after 35 years of plastic injection mouldmaking exposure this is the first I've heard of them.
Now that you've tipped your hand regarding B & L... I recently acquired a 10x and 40x objective set in a package deal and it turns out they're from a "Balplan". Wow, they're Plan! So I stick them in a '57 Dynoptic... Can see nothing, do a little reading... Oh! they're Infinity Corrected, no problem, I'll use them in an A.O., Ha!, still see nothing. More searching and I see that a Balplan tube lens is mounted on the back of the nosepiece.
The point is I'm looking for any cheap Balplan nosepiece, otherwise I've got two handsome lenses just filling up film cans. Let me know if you can help so I can jury-rig them to a bellows for pic's.
ChrisR, thanks for the input, the chemical world is truly scary! If you're inclined, check the Wikipedia and/or MSDS on Hydrofluoric acid. That's some pretty sneaky toxin!
Jim
Last edited by Retro on Fri Apr 02, 2010 9:45 am, edited 1 time in total.
Chorozon, I agree the grey epoxy seems to be an afterthought. The mirrors and tube prism along with the rest of the head are perfect.
In this case a replacement head will not be easy to find because this one (Reichart-Jung circa 1985+) has a circular dovetail base with 2 flats 120° apart machined in, providing a very close fit on assembly. With light pressure on the nylon tipped set screw it makes for a very smooth swiveling head.
Since the splitter joint is the only problem and the assembly is quite simple, the repair should be worth the effort.
Jim
In this case a replacement head will not be easy to find because this one (Reichart-Jung circa 1985+) has a circular dovetail base with 2 flats 120° apart machined in, providing a very close fit on assembly. With light pressure on the nylon tipped set screw it makes for a very smooth swiveling head.
Since the splitter joint is the only problem and the assembly is quite simple, the repair should be worth the effort.
Jim
When I first started working with microscopes in the early seventies the AO were the only scopes that used an infinity corrected optical system. The Balplan you refer to might have been out by then but I never ran across them anywhere I worked or went to school.
I don't know whether the scopes we are going to scrap are Balplan or not
but they do have the flat field system that has a lens in the body. It probably is infinity corrected without actually saying so. It also does not say 160 on the
objectives.
Methylene Chloride does not scare me particularly although you do really need to keep it off your hands.
Hydrogen Fluoride is another matter. That is on the short list of things that I really try to avoid. Where I work they are using it to dissolve fishheads into liquid suitable to be sucked through a capillary tube. Into an Inductively Coupled Plasma-Mass Spectrometer. They want everything broken down into its component atoms and a good first step for that is HF.
I don't know whether the scopes we are going to scrap are Balplan or not
but they do have the flat field system that has a lens in the body. It probably is infinity corrected without actually saying so. It also does not say 160 on the
objectives.
Methylene Chloride does not scare me particularly although you do really need to keep it off your hands.
Hydrogen Fluoride is another matter. That is on the short list of things that I really try to avoid. Where I work they are using it to dissolve fishheads into liquid suitable to be sucked through a capillary tube. Into an Inductively Coupled Plasma-Mass Spectrometer. They want everything broken down into its component atoms and a good first step for that is HF.
Last edited by g4lab on Fri Apr 02, 2010 7:55 pm, edited 1 time in total.
g4lab said:
the Balplan infinity design is unique with a lens built into the nosepiece turret. The objectives don't mention tube length, infinity or even part#, just magnification, cover slip thickness, planachromatic and the B&L name and address. They both have concave front elements with the edges of the 10x actually protruding beyond the end of its fixed metal bezel. (Explaining the slight chip)
Regardless, I only mention the nosepiece in passing because I doubt ever getting one for the price I'm willing to pay.
As for HF, I edited my post to say Hydrofluoric acid (although the first becomes the latter easily). I became curious about it when ordering the Cerium Oxide and saw glass etching paste. What shocked me was reading:
"The danger in handling hydrofluoric acid is extreme, as skin saturation with the acid in areas of only 25 square inches (160 cm2) may be relatively painless, yet ultimately fatal.
...rinsing off is not enough. In some cases, amputation may be required."
Since it is also popular for cleaning aluminium and I was recently using some new-fangled metal cleaner which burned my hands I was very relieved to learn that it was only sodium hydroxide.
Don't you love it how they leave it up to you to look up the MSDS yourself at work?
When I was 16-18, I worked in a large Textile Dyehouse full of nasty concentrates of: sulfuric acid, nitric acid, ammonia @35% BE, acetic acid 99.8% not to mention the migration salts and the dyestuffs. My main concern though was being scalded by a malfunctioning kettle control, a leak in the 300psi live steam or falling 10 feet down through the 8"x10"x12' planks between the kettles.
Anyway... I digress. Thanks for thinking about my tube lens thing Gene and do stay away from that HF.
Best regards,
Jim
It sounds like you might be referring to the "Dynazoom". From what I can determine from B&L's generously available literatureI don't know whether the scopes we are going to scrap are Balplan or not but they do have the flat field system that has a lens in the body.
the Balplan infinity design is unique with a lens built into the nosepiece turret. The objectives don't mention tube length, infinity or even part#, just magnification, cover slip thickness, planachromatic and the B&L name and address. They both have concave front elements with the edges of the 10x actually protruding beyond the end of its fixed metal bezel. (Explaining the slight chip)Regardless, I only mention the nosepiece in passing because I doubt ever getting one for the price I'm willing to pay.
As for HF, I edited my post to say Hydrofluoric acid (although the first becomes the latter easily). I became curious about it when ordering the Cerium Oxide and saw glass etching paste. What shocked me was reading:
"The danger in handling hydrofluoric acid is extreme, as skin saturation with the acid in areas of only 25 square inches (160 cm2) may be relatively painless, yet ultimately fatal.
...rinsing off is not enough. In some cases, amputation may be required."
Since it is also popular for cleaning aluminium and I was recently using some new-fangled metal cleaner which burned my hands I was very relieved to learn that it was only sodium hydroxide.
Don't you love it how they leave it up to you to look up the MSDS yourself at work?
When I was 16-18, I worked in a large Textile Dyehouse full of nasty concentrates of: sulfuric acid, nitric acid, ammonia @35% BE, acetic acid 99.8% not to mention the migration salts and the dyestuffs. My main concern though was being scalded by a malfunctioning kettle control, a leak in the 300psi live steam or falling 10 feet down through the 8"x10"x12' planks between the kettles.
Anyway... I digress. Thanks for thinking about my tube lens thing Gene and do stay away from that HF.
Best regards,
Jim