Mamiya RB67 leaf shutter pin prick hole- ideas?

[FONT=Verdana,Arial,Helvetica][FONT=Verdana,Arial,Helvetica]Hi Everyone,

I am scratching my head on this one. I have a 90mm RB67 lens that I have torn apart to rebuild. I have done 3 of these lenses and shutters with no problems. This new one has a 2 pinholes on one of the metal shutter leaves. Does anyone have any ideas other than tearing down the the shutter and swapping the leaf out, for patching the hole. A friend mentioned to me to use a pinprick of JB Weld, while compressing from the other side with wax paper.

I thought of micro soldering to plug the hole.

I also might patch it with that really thin self stick aluminum metal tape.

I might even just use some thick super glue and quick bond agent to freeze it in place and then color it with a permanent black marker.

Anyone have any other ideas, for this predicament?

I do have another lens I can swap out the blade, but wanted to keep the shutter intact if I can.

check out the photos. [/FONT][/FONT]

Man that looks like a tough fix. All the alternatives you have mentioned will build up too much thickness. You will still have to take it apart and sand it down really flat to not have friction on other blades or you might risk binding or even creating another pinhole. Friction would also affect speeds.

I you get it apart, maybe a coat of paint across the entire surface of that blade, can patch it on both sides. The paint would be drawn into the hole. Durability would depend on paint type and thickness.

Try finding another shutter or parts body to do a swap. Thats the sure way. Patches even if they do work, may fall apart and end up binding the shutter anyway.

I think silver solder would do the trick. Get the silver good and hot so it flows into the hole then, after it cools and hardens, polish it smooth.

How about just leave it be? Does it add that much exposure in the grand scheme of things?

Greg Heath said:

[FONT=Verdana,Arial,Helvetica][FONT=Verdana,Arial,Helvetica]Hi Everyone,

I am scratching my head on this one. I have a 90mm RB67 lens that I have torn apart to rebuild. I have done 3 of these lenses and shutters with no problems. This new one has a 2 pinholes on one of the metal shutter leaves. Does anyone have any ideas other than tearing down the the shutter and swapping the leaf out, for patching the hole. A friend mentioned to me to use a pinprick of JB Weld, while compressing from the other side with wax paper.

I thought of micro soldering to plug the hole.

I also might patch it with that really thin self stick aluminum metal tape.

I might even just use some thick super glue and quick bond agent to freeze it in place and then color it with a permanent black marker.

Anyone have any other ideas, for this predicament?

I do have another lens I can swap out the blade, but wanted to keep the shutter intact if I can.

check out the photos. [/FONT][/FONT]

Click to expand...

Wow, how on earth did that get there? Corrosion?

The suggestion of opaque epoxy is pretty good, if you carefully scrape the repair flush with the leaf, it should work.

I

Seriously? Get a new shutter from a dead/diseased donor lens or just get another 90/3.8. Don't try Bondo, either.

If you really want to get fancy and complicated, you could plate it shut with copper, or rivet a tiny patch over it.

I picked up two old 90mm lenses in hopes of getting at least one to work.

The one with the operable shutter has the pinprick holes...and a slightly fungus'ed rear lens. I have already cured that with a 50/50 mix of Ammonia and Hydrogen Peroxide. I really didn't want to do a complete tear down piece by piece on the shutter, as I usually take out the lenses and the body and then soak the whole shutter in White Gas (Coleman lantern fuel), and then after a 15 minute soak, I turn on the Ultrasonic cleaner and let that run for 5 minutes. Usually whatever is causing the jam, is jarred loose, like dirt and grime and then I completely rinse it in fresh white gas, and then when it dries overnight I oil the spindles of the gears. That's about it. Runs great after that. I clean and reinstall the elements and rings and it runs like a champ.

The other lens has a jammed shutter, so I will in fact tear it down and make it a parts shutter. Both lenses are old enough (1970-72) that they have Type "a" blades, so it should hopefully be a quick repair.

This is not for my camera, it's for a friend. I want to make sure she has no problems, and the lens is in top shape. $40 for both lenses shipped. It has been fun. Thanks for the replies, and the laughs. It really is microsurgery. My guess is the holes were caused by corrosion. I removed the rust from the blade with a fiberglass pen. I love that thing..

Dead Link Removed

So it's either try to patch it or replace it. I might try both. replace it, and then do some practicing on what method works. The pin holes are at almost the base of the blade, so not sure about centrifugal "g"'s and it coming loose. If I can patch the blade, I will scrape off the rest of the paint around it, and then try a micro brush with the smallest amount of JB weld... These holes are tiny. I bet it will work. Worst case scenario I'm out $40. Best case scenario it works and I gain some knowledge about the Mamiya Shutter That and couple more gray hairs on my head. The JB weld is made for metal, but I will have to use the slightest mixed measure. plus it's black/gray colored. the rest of the paint that I will take off I can fix with dye, or my cheap alternative of a permanent black magic marker.

I love a good challenge.


Greg

E. von Hoegh said:

Wow, how on earth did that get there? Corrosion?

The suggestion of opaque epoxy is pretty good, if you carefully scrape the repair flush with the leaf, it should work.

I

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I lived in the Adirondacks for 3 years (Plattsburgh).

Greg Heath said:

I lived in the Adirondacks for 3 years (Plattsburgh).

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I've lived in that area for 35 years, nothing like that has happened to any of my gear.

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

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.

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

IT LIVES !!

sound: flash of lightning...


Muhahahahahaha...

FRANKEN-LENS !!!

:eek:

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

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.

.

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

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.

.

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

paul ron said:

Most shtters I've opened are never that dirty.

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Well, there was this bar in Tijuana...

Greg Heath said:

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

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You have found a use for hypo eliminator!

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