Mamiya RB67 leaf shutter pin prick hole- ideas?

[Greg Heath]

Well this is a parts find on ebay. I do not know the background on these lenses. I have never seen a corrosion hole on a camera shutter before, so my thoughts are that it was in someone's basement and their basement flooded. That would explain the fungus on the lenses, and the seepage marks on the outer body. It make sense the corrosion. There was other corrosion on the some of the other blades but I cleaned them up. I think this shutter will be a complete teardown. I might even give my friend my own nice 90mm and just use these myself for fun. No sense in sending her possible junk. If there is fungus, I will treat the whole lens in the solution and rebuild it. It's like a giant jigsaw puzzle. Plus I have the Mamiya Parts manual, so it won't be as tough as it would be having nothing to refer to like normal.

The greatest thing is that the Mamiya Seiko shutters are huge compared to the Agfa shutters I do regularly.

Greg

[lxdude]

I never knew Mamiya made pinhole cameras...

Other than replacing the shutter, I think the paint idea is the best-and it is the easiest. As stated, the paint will get drawn into the holes, and after it dries the paint on the face of the leaf can be carefully removed with a cloth with a small amount of solvent on it. Some other thin opaque liquid could be used instead with the same technique, but I doubt anything would work better on pinholes than paint.

[Greg Heath]

I'm just not sure that paint is going to hold up. I'm going to head to the art store in the morning and find the finest paint brush with a fine tip, and buy a couple.
I am going to try the JB Weld. I will hold wax paper to the other side and ever so gently brush in to fill the holes. Then just let it cure. We are talking just such a tiny amount, not spreadable gobs. I think in one application, maybe 2, the second being lighter, will fill the corrosion hole. It will be interesting. If that fails, then I will take the shutter apart. I will first soak the entire shutter in the white Gas and thoroughly clean it, which should prep the hole by removing any impurities. I will post the photos of the after effects. I would have done it today, but there was a World of stuff to do not related to my hobby.

Greg

[Greg Heath]

IT LIVES !!

sound: flash of lightning...


Muhahahahahaha...

FRANKEN-LENS !!!



the 50/50 mix of hydrogen peroxide and ammonia ate the fungus off the lenses. They are perfectly clear now. YEs!!

I actually split the other shutter I had, and replaced the defective rusted shutter blade. It was a perfect match.
Now I will try to fix the defective blade and reinstall it in the other shutter/lens. If I am not successful, I will have a parts lens for folks who need a part or two..

Greg

[paul ron]

I did a lot of backpacking in the ADKs for a good 30 years n never had that happen.

If it is a good shutter, n u have a junker laying around, take the time and swap the leaves.

I recently gave away a junker for parts, I'll look in the closet I may have another.

.

[Greg Heath]

Thanks for the offer of some parts. So much appreciated. I am currently putting the 90mm back together. Now that I have figured out how to split the shutter, it is a piece of cake. It helps that I have so much experience for the past 2 years with the smaller shutters, like Pronto and Compur-Rapid. These big ones are nice, cause you can actually see what you are working on, without using a magnifier 100% of the time.

I'm still going to try to somehow fix that other blade to see what could possibly work.

But Here are some of the pics..

This photo is enhanced HDR. The shutter plate did not have chipped or an worn surface.

Here is 40 years of grime and dirt on the shutter plate. I even found parts of a grass weed inside the shutter. Unreal.



so now someone will get a nice reworked, and repaired shutter.


Greg

[paul ron]

Cheese where did you find that thing, in a swamp? Most shtters I've opened are never that dirty.

Now that you have the leaf out, try black bondo, it should work fine if you polish it to a 1600 grit wet dry n get a nice sleek finsih on it.

.

[Greg Heath]

Awesome deal. 2 Mamiya RB67 90mm lenses. $40. I was hoping that I could have gotten both working, but surprisingly,the water damaged lens was in really great shape, except for the dirt and the corroded blade.

The Best deal I ever got for 2 lenses were two 127mm lenses for $28. The barrels had brassing but the glass was flawless. That was from KEH.com (love that place)

Now If I could find a flawless Hasselblad or Leica for $25 in the parts bin.

thanks for the bondo idea...I'm still thinking about it. I was considering using some JB Weld.


Greg

[lxdude]

Most shtters I've opened are never that dirty.

Well, there was this bar in Tijuana...

[ic-racer]

the 50/50 mix of hydrogen peroxide and ammonia ate the fungus off the lenses.

You have found a use for hypo eliminator!

Does it really remove haze that does not easily wipe off?