Nikon 8mm f/2.8 Ai - filter carousel

[Kuri]

Longzoom, Sounds like some kind of epoxy, given the 2 part mix, which would not need the full circumference, like you said, especially if you painted the filter edges black.
Probably a few points of superglue gel would work, just enough to keep them from falling out.

Sure would be interesting to know the glue they originally used.

Akira, UV cure is what I generally use for laminating (gluing) glass together, like say U-360 glued to S8612.
However the adhesives I use for that are extremely tough, and need to be soaked in solvent for a day to weeks to remove them, depending on the solvent.
With all the solvents I tried, I never 'soaked' the revolver, because I didn't want to remove the painted colored filter labels from the edges of the revolver plate.
I am pretty sure many glues will work for cementing new filters in the hole, but it would be nice to use something that is not so hard to remove.
So far anyway, I am not a glue expert. :-) 
But this make me wonder what kind of glue would be good for holding the glass in the holes, but still be easy to remove, even maybe with water, or some solvent that will not damage the paint or labels if soaked for days...

Erik, The repair manual mentions 'binding agents', page 4.
See the section where is says, "...or glass with metal", but it lists, 4 different #'s only... #616, #621, #631, and #634.  None of which I have any idea what they are.
Maybe one of those is what was used... but I don't know what those #'s are.



 

[Akira]

FWIW, Kuri:

#616: Cemedine Super and Cemedine #1500
#621: Cemedine #1565
#631: Araldite AT-1
#634: Base resin: Araldite AY101, Hardener: Araldite HY951

All adhesive are 2-part mix epoxy.  Cemedine is one of the leading adhesive company in Japan.  At least Cemedine Super and #1500 seems to be readily available.

[pluton]

"Superglue"(cyanoacrylate, methacrylate) has outgassing issues.  It is not recommended for parts in lenses that will be placed into an air-sealed environment.  I have seen the outgassing leave deposits on lens elements.

[Akira]

The "superglue" is only indicated "For the temporary adhesion in the process" rows.  #921 and 922 are the adhesive of such type.  "Aron Alpha" is their product name, is very popular here in Japn and, according to wiki,  sold as "Krazy Glue" in foreign countries.  Other temporary adhesives indicated are shellac (#201), screw lock (#350: kind of locktite) and locktite (#410, yellow, red, purple, blue and orange).

[Kuri]

Akira, Thank you for translating that!  That really sheds a lot of light. Sounds like the adhesive is epoxy.
In my understanding, super glue and Krazy Glue are essentially the same thing, just different names.

Pluton, Thanks for the heads up about out-gassing of Supper Glue.
I will stay away from that then.

I wonder if silicon would be OK, easy to separate. 
Thank you very much for your input and ideas about this.

[Kuri]

The shape of things to come. Work in progress.

[Akira]

Looks nice, Kuri!

One coaution: Schott BG38 as well as BG40 glasses are fairly easily deteriorated (supposedly by the moisture).  Both of my samples shared the same destiny.   

It would be advisable to see to it that BG 38 is glued only lightly so that it can be replaced easily.

[Erik Lund]

Looks like a very good job! Looking forward to the images

[Kuri]

Thanks Akira, and Erik. 
I don't have those glued in yet. I think it was some kind of epoxy, as you translated, but I have not decided what to use.
The glass is cut to be tight, same as the original size, and they pretty much 'snap' into place and stay there, but they might need a bit of a light seal between the glass and the footing.
As far as BG38, I have used BG38 and BG40 forever, and never found any surface problems with those two types of glass myself, in my location.
S8612 (and similarly BG39) are the more prone to surface deterioration.
I recommend polishing those with Cerium Oxide slurry, whenever possible to keep them free of surface problems.
But that needs to be done before deterioration becomes too advanced, otherwise the Cerium Oxide will not work.
Here are the pertinent warnings for those 4 glass types::

BG38 (no warnings)
BG40 [!] Long-term changes in the polished surface are possible under some circumstances.
BG39 [!!] Long-term changes in the polished surface are possible.
S8612 [!!] Protective coatings recommended. Long-term changes in the polished surface are possible.

BG38 is my preferred glass for visual on a full spectrum camera.  Baader UV/IR-Cut looks too red to me. BG440 also works well, but S8612 looks too blue to me, and this is after white balancing out of camera.

[Akira]

Kuri, the environment in which I stored BG 38 and 40 wasn't that humid, but the surfaces of both glasses became "sticky".  Apparently the surface was melt with moisture.

FWIW, my Hoya U330 was deteriorated in the same envionment as well.  Its surfaces are fogged.  My U360, again, stored in the same environment hasn't been deteriorated at all.

[Kuri]

Akira, Yes, U-330 and UG5 are prone to that also, as well as UG11 and U-340. UG1 and U-360 are more stable, and I have not seen issues with those two U-glass types, and those don't have warnings as the others do.
BG38 is the most stable, I have never seen any problems with that type of glass, which I work with on a regular basis, so not sure what is going on with your BG38.
I have seen the 'sticky' thing before, usually with S8612, which should clean off.
My general advice for any surface problem on non coated class is:
1) clean with hydrogen peroxide and/or other cleaner (first), even soak it for however long.
2) then polish with cerium oxide.
That should remove any surface problems that are not eroded into the surface of the glass.
If there is erosion into/below the surface, then that can't be removed, it would need to be resurfaced, which can be almost as expensive as a new filter.

[Akira]

Kuri, I hadn't used my BG filters for months when I found their surface sticky.  And the sticky layers were already too thick to remove.  I don't think they could be cleaned anymore.   

U330 became foggy just on the surface.  It is unusable as optical part, but should be able to use as UV-pass filter for a flash.

[bobfriedman]

i want one!

[Kuri]

Bob, I know. :-)

Akira, I would try cerium oxide on both, worth a try, if the surface of the glass is not etched/eroded, then the cerium should remove the problem, but it is hard to know until you try it.

Cerium oxide is available on eBay, etc., in powder form, just mix with water like mud. Also available already mixed in bottles.
Get the good stuff, not from China, often they mix zinc with cerium to make it less expensive.
Either pink or white will work the same.

[bobfriedman]

Bob, I know. :-)

i spend any amount of money that it takes to have one.. well perhaps not.