MicrobeHunter.com Microscopy Forum

I was cleaning up at work (Middle school) today. And at my surprise I found three nice old binocular microscopes at the bottom of a cabinet. Well with some backward maintenance.
I start the repair of the first one now. It is a Leica Stereozoom 6. Mechanically this is fine if I put new grease in it (and removed the old one first).
What I no longer get right is the last lens surface, there is a kind of fog on it. See the pictures. I have tried various solvents. No effect. Is this lens still to get clear?
Or should I learn to live with it. Even with a damaged lens, the image is still remarkably good

Perhaps permanent mold damage? A bummer but if it still works it could be worse.

The Leica Stereozoom 6 was the binocular was the one with the damaged lenses.
I also found same binocular with name Bausch & Lomb (exactly the same) ; these lenses where nearly perfect clean.
I compare these 2. In sharpness there is not a big difference.
The Leica has less contrast, slightly more affected by light flare. And remarkable the black are not black, the blacks are more greenish.

Looking closer (now that I'm on my desktop) the SZ6 does alas look to have permanent mold damage. It happens, not much to be done about it.

The compound head looks delaminated. Bausch and Lomb sold Olympus scopes (as the "Galen I") Kyowa scopes (as the "Galen II") and Chinese scopes (As the "Galen III", which I think was a Chinese copy of the Olympus BH2) so it could be any of those, which were also sold under other names. It would be worth taking a photo of the whole system to know which one you're dealing with.

Found this
https://www.instructables.com/id/Glass- ... al-Lenses/
Doubt may be I try

Before you do: may seem strange but first give it another try using demi-water plus a drop of fairy dish wash liquid.
It cleaned way beter than the usual candidates and saved 2 of my stereo-zooms.

It did Not help on a fogged Reichert lens: lightly polishing with a mix of demi-water and cerium oxide on a old towel around a fingertip did the trick.

Good luck, deBult

cmug wrote: ↑

Fri Apr 10, 2020 5:17 pm

Found this
https://www.instructables.com/id/Glass- ... al-Lenses/
Doubt may be I try

As someone who's ground a little glass, if you try this it is very important to vary the motions a little so as not to introduce zones; imagine motions similar to the precession of the pole on the planet. I would advise you to not use a rotary tool, instead preferring to do it by hand. The amount of time it should take to repolish the surface should be very little, maybe 15 minutes as you aren't trying to change the figure of the lens, just polishing the surface. Make absolutely certain the surfaces are clean, a tiny grain of grit between the glass and tool can easily score the lens and make matters worse. Clean and rinse carefully!

Scarodactyl wrote: ↑

Mon Mar 30, 2020 9:13 pm

Looking closer (now that I'm on my desktop) the SZ6 does alas look to have permanent mold damage. It happens, not much to be done about it.

The compound head looks delaminated. Bausch and Lomb sold Olympus scopes (as the "Galen I") Kyowa scopes (as the "Galen II") and Chinese scopes (As the "Galen III", which I think was a Chinese copy of the Olympus BH2) so it could be any of those, which were also sold under other names. It would be worth taking a photo of the whole system to know which one you're dealing with.

The one Galen III I have seen is smaller than the BH2 and not really a match in terms of quality or exapandability. It was made by Cambridge Instruments in China AFAIK.

Copy in a broad sense (I have heard the heads are compativle for instance) but apparently not an exact clone.

I bought Cerium-oxide. Circa 0,5-1,0 micron. And did the experiment. Make a paste from the Cerium-oxide and distilled water. Used an Dremel polish + PEC pad at top. And polish for ~ 20 minutes. After the polish The glas was much better, still not as new.
Unfortunately, it was only possible to process the lens on one side.
Visually, the lens is now better.
But. . . Looking through the bi-ocular, the image has become slightly worse. So conclusion: experiment failed.

Sorry to hear the polishing did not work out.

Ehh: As stated: I polished lightly with a fingertip in an old towel ..
Using a Dremel for 20 minutes probably changed the lens curvature??

deBult wrote: ↑

Mon Apr 20, 2020 5:03 pm

Using a Dremel for 20 minutes probably changed the lens curvature??

Hard to tell, but probably not if the polishing wheel is soft enough. I'm used to using pitch for the polishing lap, but I am aware some people have used felt pads to good effect. Were it me, I'd heat up some pitch and give the lens a couple passes, but I realize most people (the sane ones at least) don't have pitch just hanging around.